PV solar power photovoltaik

Table of Contents

General

Information sources and todo:

Andreas Schmitz erklärt auf YouTube wie eine Anlage dimensioniert wird muss, damit sie sich schnell ökologisch und monetär amortisiert, Auswahl der PV Technologie und vor Auswahl des Aufbauortes, ab Minute 4:20 und ab Minute 5:25. Er nutzt PVGis – Photovoltaic Geographical Information System. Hier eine Schritt für Schritt Anleitung, um den Ertrag einer PV-Anlage zu berechnen.

Selbstbauprojekte zum Basteln und Experimentieren:

Components

Systems

We are working with several separate small PV systems:

PVH

PV Hip roof &Ndash; 800Wp Balkonkraftwerk on the south-facing hip roof (walmdach) at south end of the house:

Done:

Todo:

PVL

800Wp balkonkraftwerk on south-facing balcony roof + east-facing roof ridge:

Done:

Todo:

PVM

PV Middle, an off-grid system feeding moniwonig, galvanically separated from the mains grid by an automatic two-way switch. Due to suboptimal and conflicting panel orientations, PVM never reaches its theoretical peak performance. PVM maxes out at about 875W under the best possible conditions.

PVM supplies most of the required electricity for the rather frugal two-person moniwonig household consuming 456 kWh/year (2022) and consists of the following components, including three separate strings of PV panels and chargers, battery, BMS amd inverter:

It could generate more electricity, but there is nowhere to store it once all loads have been covered and the battery is full.

Due to the different panel orientations, neither of the first two can ever reach their theoretical peak performance. PVN maxes out at about 450W and PVM at ca. 875W under the best possible conditions.

PVM supplies most of the required electricity for the rather frugal two-person moniwonig household consuming 456 kWh/year (2022) and consists of the following components, including three separate strings of PV panels and chargers, battery, BMS amd inverter:

It could generate more electricity, but there is nowhere to store it once all loads have been covered and the battery is full.

Logs

Here are the PVM battery voltage, three charger currents and resulting Wh generated for a couple of days in October 2023, from Oct 2-4 and 5-10:

The sudden dips in the battery voltage indicate when the hot-water heatpump (ca. 500W) and the milk foamer (800W) are turned on.

Update Idea

Now that PVH and PVN are producing satisfactory results using microinverters, it might be a good idea to rebuild PVM based on that technology as well.

The 400W east-facing and south-facing panels could be connected to one single Absaar AB800A microinverter, and just use the vertical-facing panels with the existing 24V off-grid system.

So, if I reconfigure both the east and south facing PV panel strings into 2 groups in series of 2 panels each in parallel, they each produce max. 44V and 11A, perfectly in range for the microinverter.

Bought an NEP BDM-800 microinverter that ought to fit the bill:

Nope, PVM is still running, maybe just needs a new BMS, e.g., active JK instead of passive Daly.

Use the NEP microinverter for a new PVL system instead.

BMS and LiFePO4 Cell Replacement

In October 2024, the PVM 200Ah 24V LiFePO4 battery with the Daly BMS started failing frequently. The BMS would disconnect the battery when the sun was shining too strong, and later systematically every night after sundown. Presumably, this was caused by the cell voltages drifting too far apart.

In the beginning of December 2024, I replaced the Daly BMS with a JK BMS, and suddebly all was well again. The cells are still a little bit apart, but the active balancer compensates enough for them to work fine with no interruprion.

In January 2025, I replaced the VariCore 200Ah LiFePO4 cells with EVE 280Ah ones and performed some detailed logging:

PVN

Short for PV North.

PVN consists of 4 Replus 250 microinverters, each of them fed by 3 Wuerth 75 W panels.

Set up a grid-bound PV system on the north lean-to roof over the aussenkueche:

The microinverter handles max. 270W. 3 panels produce max. 225W, 4 max. 300W.

Initially I planned to connect 3 groups of 4 pv panels in parallel and a fuse to disconnect one of the four in case of overload. Some articles quote max. 220W for each microinverter, so I decided to use all four of them that I have anyway and just connect three panels in parallel to each one. So, 4 groups of 3 PV panels each in parallel, and we are well below the max inverter capacity.

PVN maxes out at about 450W under the best possible conditions.

done:

shop:

PVS

Short for PV South. Set up a grid-bound PV system on top of the wood stack on the south border using 3 x 300W SG300MS microcontroller, each of them fed by 4 x Wuerth 75 W panels, each one feeding a different phase of the south 3-phase electricity.

Electricity generated in kWh by PVS1 + PVS2 + PVS3 (consumption reported by wld electricity meter):

2024-05-13 0.0 = 0.0 + 0.0 + 0.0 (372.2) 2024-05-17 1.6 = 0.0 + 0.0 + 1.6 (-) 2024-05-18 2.5 = 0.0 + 0.2 + 2.3 (374.6) 2024-05-19 4.8 = 0.4 + 1.1 + 3.3 (376.5) 2024-05-20 7.4 = 1.0 + 2.1 + 4.3 (379.2) 2024-05-21 8.5 = 1.24 + 2.56 + 4.74 (380.3) 2024-05-22 7.1 = 1.62 + 2.94 + 5.49 (382.2) (mitte reported kWh total 0.0) 2024-05-26 11.1 = 3.07 + 3.39 + 8.01 (388.9) (mitte reported kWh total 0.0)

done:

todo:

shop:

System Sizing

According to the MPP Solar system sizing guide, the most important and common questions every system designer faces are:

These questions can be answered by using simple arithmetic operations. Solar array sizing requires calculating the total energy in kWh and divide it by the number of peak sun hours. Battery bank sizing also starts out with the total energy requirement, the backup days in case of no sun and the maximum battery DOD (depth of discharge):

Solar array sizing calculation:

W = E ÷ G ÷ Ksys

Where

Battery bank sizing calculation:

Q = ( E x A ) ÷ ( V x T x Kinv x Kcable )

Here is another PV sizing calculator by EPever that sums up loads, both daily and peak, and sizes batteries, solar panels, charger and inverter.

Auch beruecksichtigen: beim Heizen mit Solar und Wärmepumpe lohnt sich ein grosser Pufferspeicher besser als Akku.

Consumption

Treppenlicht

Beispiel Treppenlicht im Huenerbergweg 30:

Verbraucher:

Maybe we ought to run a new 220 V line down to the basement, and just hook up the plugs to new wires.

We could also grab the 220 V for the plugs from the drehstrom installation…

Or both, in parallel, in case the battery runs out…

Moniwonig

Main consumer is Moni’s fridge: it uses 0.522 kWh per day, 190 kWh per year.

2021-04-07 18:00 started monitoring fridge electricity consumption using Pearl SD-2209-675, originally revolt SD-2209-675.

Moniwonig 2022-07-22

Empirical Moniwonig yield results February - July 2022; unfortunately, January is missing; the PV system was down then. East panel charger yield E from 400 Wp is what the charger fed into the battery or directly into the inverter. The consumption C is the 220 V AC consumption after the inverter from all three PV panel configurations E + S + V with a total of 0.4 + 0.4 + 1.6 = 2.4 kWp, partly shaded, including all system anbd conversion losses. E, C and average E and C per day in kWh on various dates between February and Julky 2022:

datedaysCEC/dE/d
2022-02-05n.a.15542n.a n.a.
2022-02-105164 451.5 0.48
2022-02-2010176 481.2 0.30
2022-03-0210193 521.5 0.47
2022-03-1917221 621.7 0.56
2022-07-22125571 1692.80.85

Mounting

Auf den Dachsparren unter den Ziegeln werden Dachhaken angebracht, die zwischen den Ziegeln hervorschauen und die PV-Montageschienen tragen. Die Schienen tragen die PV-Panele, die mit Klemmen befestigt werden. Schienen muessen eventuell zum Verlaengern miteinander verbunden werden.

Die Montageschienen muessen alle miteinander verbunden und geerdet werden; dazu muss ein Erdungskabel (16 mm2) an der Unterkonstruktion angeschlossen und mit einer sicheren Erdung verbunden werden.

Solar Analysis

Sonnengang am Sonnenweg: unsere Nachbarin gegenueber Waldrain, teilt mit: Im Sonnenweg 3 scheint die Sonne von ca. 11 Uhr bis 11.30 Uhr (je nach Jahreszeit) durch und über den Waldrain, macht während des Tages ihren Gang, hat an Hochsommertagen von ca. 14 bis 14.30 Uhr an ihren Höhepunkt bis ca. 18 Uhr. Das heisst, sie gibt so viel Wärme, dass ich dann auf meine Terrasse Waldrain gehe und dort das hervorragende, ja herausragende, ja fantastische Waldrain-Feeling total geniesse… Gegen 18 Uhr gehe ich dann auf meine Sonnenrain-Terrasse und geniesse den Abend bis in die Puppen…

Frage: Was fuer ein Winkel und Ausrichtung ist fuer eine PV-Anlage optimal?

Antwort: Ca. 45° bringt den höchsten Jahresertrag. Wenn das Ganze in Richtung Autarkie optimiert werden soll, bringt eine Ost-West-Ausrichtung oder Süd-Ost / Süd-West einen gleichmässigeren Tagesertrag. Das kann aber auch eine Batterie ausgleichen. Für mehr Ertrag im Winter: steiler; dann wird dafuer im Sommer wird weniger Strom produziert und ins Netz gespeist.

Roof Surfaces

Analysis of potential pv panel placement roof surfaces in H30.

Dimensioning: on the north half of the house, each tile measures 20 x 33 cm. So, one square metre is 5 tiles wide and 3 high. On the south half, the tiles are slightly larger, ca. 225 x 336 mm, so 4 tiles wide x 3 high measure ca. 90 x 101 cm.

Also entspricht 1 quadratmeter exakt 5 x 3 Ziegel (b x h) auf der Nordhaelfte.

The moniwonig PV system uses the first three E, S and V.

Remaining surfaces available:

We have 40 Wuerth panels 0.6 x 1.2 each, 29.2 qm total. That would fit into E top + bottom. Top fits them in vertical pairs of 2 with a total height of 2.4, 6 + 10 wide = 3.6 + 6 meters. Or, equivalently, in vertical strings of 4 with a total height of 2.4, 3 + 5. That provides space for 32 panels out of 40.

In E bottom, we can place them in two groups of four each horizontally between the three windows, 1.2 meters high and 2.4 wide, taking care of the 8 but leaving no space for movement. Or, we add three higher up and further right, upright beside each other below the north chimney. Or, just two below the north window, tilted up from the roof and facing due south.

Better: add seven to the left of the roof division line, and one just right of it, cf. the NE roof pv panel arrangement sketch.

With the 40 panels on the NE roof, we have 3 kWp, Dachausrichtung -56 degrees (0 = S, -90 = E), Neigungswinkel 45 degrees. According to echtsolar.de PV-Ertragsrechner, the yearly yield will be 2712 kWh with only 73 and 76 kWh per month in december and janaury, respectively, over 2.3 kWh per day.

Comparing with the EGM + EGN consumption: in 2021, it was 1480 kWh for the entire year, ca. 4 kWh per day.

Scaling up the moniwonig yield from the existing E panels’ 400 Wp to the new panels’ 3 kWp, we may be able to achieve a factor 3/0.4 = 7.5 higher value; the minimum of 0.3 kWh/d converts to 2.25 kWh/d, pretty precisely matching the theoretical 2.3 kWh/d calculated above.

2022-08-24 update: I can only use 20 Wuerth panels. They can be placed on the east facing roof at the north end just below the roof ridge between the two north chimneys: w x h = 624 x 230 cm.

2022-08-25 new idea: cover the upper balcony with a solar panel roof to protect from both rain and sun. between the two chimney on the north-east quarter of the roof, that would provide an area of 30 qm. the axitec panels produce 200 Wp per qm, so 6 kWp on 30 qm. 12 axitec panels would require 12 x 1.75 = 21 qm. the wuerth panels produce only 100 Wp/qm; 20 x 0.75 = 15 qm.

Other panel placement options

Neigungswinkel fuer PV im Winter

Die Sonne steht im Sommer ganz anders, als im Winter. Im Winter ist der Eintreffwinkel der Sonnenstrahlen sehr flach. Die Sonne steigt im Winter nicht so hoch, wie im Sommer.

Die optimale Ausbeute einer Photovoltaikanlage wird dann erzielt, wenn die Sonne genau auftrifft (im rechten Winkel). Der optimale Neigungswinkel im Winter ist also viel höher, als im Sommer.

Dieser lässt sich sogar berechnen. Die Formel lautet (Dreilaendereck liegt auf ca. 47.6):

Allerdings muss beachtet werden, dass die optimale Dachneigung im Sommer viel niedriger ausfällt. Insgesamt gibt es immer eine Mischkalkulation zwischen Neigungswinkel und Ausrichtung über den gesamten Jahresverlauf.

Several PV Panel Strings Facing Different Directions

Eine PV Anlage mit mehreren Ausrichtungen aber nur ein Wechselrichter – geht das?

Solar Panel

Current sets of PV panels and directions:

South

This is the data sheet for the first four solar panels on the south-facing balcony roof for 192 euro, 48 cent/W.

Panel data:

Array configuration: all four in series → max 5.62 A, max 88.4 V, max 400 W

East

Second set of four panels in series along the east-facing roof ridge for 196 euro, 49 c/W:

Panel data:

Array configuration: all 4 in series → max 5.56 A, max 88.8 V, max 400 W

Vertical

Horizontal shed roof with seven pairs of cbl used panels Shell S115 facing vertically and slightly north with some shade. Later: tilted them slightly southwards with a brick each.

Panel specs:

Array configuration: 7 pairs of 2 panels in series each → max 32.9 A, max 65.6 V, max 1600 W; due to the shading, they will never reach that peak performance.

Cbl paid 500 for 20 panels with 115 W each, i.e., 22 c/W.

Wuerth

40 Stück 75W Würth Dünnschicht PV Solarmodule WSG0036M075 for 798 euro, 26 cent/W:

Array configuration: a string of ten each would provide max 431 Voc and 340 Vmp with max Isc 2.4A, four such strings in parallel would provide max Isc 9.6 A. With 20 panels, two such strings of ten in series each would produce 340-430 V and 3.4-4.8 A.

The free space on the south facing balcony roof with 3 x 1.3 could accomodate 5 of these panels producing 375Wp.

Trina

Trina PV panel with a broken glass cover, gifted by Marco.

Siemens SM 100-24

Wolfram offers 20 Siemens SM 100-24 panels. They were installed in 2002, 20 years ago.

Axitec

Von Dubicki auf ebay:

Znshinesolar

Joerg bzw. Detlev hat panele von Znshinesolar:

10 * 46.5 = 465 V 2 * 9.12 = 18.24 A 20 * 325 = 6500

Trimax

Trimax Broschuere

210-132 – TMX 655 MH9-132A

A string of ten would deliver 380 V, 17 A, 6460 W, on 31 qm.

The PIP8048MAX charger could handle two such strings, requiring 62 qm panel surface.

Let’s go for one array to start with: trimax 210-132 TMX 665 MH9-132A.

Isofoton

69 Isofoton modulo fotovoltaico I-100 monocristalline PV panels, used, 15-18 years old, leistungsgarantie 25 years, label, data, for 699 euro; assuming they still provide 80% of their nominal power, they will provide 5.5kWp and cost 13 cent/Wp:

Tidesolar

Bought together with cbl and dieter four pallettes a 36 panels, 54 for dieter and 90 for me:

We explore how to place Tidesolar PV panels on the H30 NE roof quarter:

TD-400MC-108HC:

Areas A + B max size = 3700 x 2600 + 6300 x 2600 mm. Area A would fit 2 x 2 panels taking 3448 x 2268 mm. Area B would fit 3 x 2 panels taking 5172 x 2268 mm. That arrangement accomodates 10 panels providing 4 kWp.

meine berechnung in revit hat ja ca. 4.5 MWh/a ergeben. die sunny berechnung mit tide und 4 kWp auf eine etwas kleinere flaeche ergibt 3.8 MWh/a. das passt.

die problematischten monate sind ja januar und februar. in januar 2023 haben OGN + DGN zusammen 206 = 88 + 70 (3phasen) + 48 kWh verbraucht laut sunny produziert die tide-anlage in januar 117 kWh. bisschen knapp.

Let’s look at areas A + B + C + D + G. For the large panels, we had better combine C+D into one. C+D offers ca. 1900 x 1900, which can fit 2 panels taking 1724 x 2268, slighly overlapping the left-hand bottom corner of A. A still offers space for 4 = 2 x 2 panels as before, moved away towards the upper right. B hosts 6 = 3 x 2 panels. G can host 2 more. Finally, let’s switch from the 400W modules to 410W ones,

TD-410MC-108HC:

ET-M754BH410WW/WB Tier One:

18 panele verlegt, 7380 Wp, flaeche ziemlich ausgereizt; jedes blaue rechteck ist 1730 mm x 1140 mm gross, 6 x 6 mm groesser als die pv-panele:

18 Tidesolar panels
ComponentAmountNote
Roof mounting hook52 pcDachhaken
Mounting bracket57 mMontageschiene
Bracket connector8 pcSchienenverbinder
End clamp30 pcEndklemme
Middle clamp21 pcMittelklemme
PV panel18 pcTD-410MC-108HC 7380 Wp 675 Voc 14.15 Imp
PV cable 2 metre4 pc700V 15A 5mm diameter
19mm2 cross section area
PV cable 9 metre2 pc
PV disconnector1 pcDC circuit breaker + surge protection + fuses
Inverter1 pc1000V DC in 230V 3 phase 8kW AC out
Storage1 pc20kWh 48V DC battery

Detailed list of mounting bracket dimensions, total 56.6m, assuming panel size including clamps 1.2 x 1.8 m:

Dachhaken: 3 + 3 + 4 + 4 + 2 + 2 + 3 + 3 + 4 + 5 + 5 + 5 + 2 + 2 = 47 Stueck.

Cables

To select a suitable wire gauge and cable size, please refer to the cable wire size gauge chart and Aussendurchmesser gebraeuchlicher Kabelquerschnitte.

I bought wire from zaehlerschrank24.de.

My rooftop panels are connected with 6 mm2 solid copper wire:

Up to 10 meters length and 40 A current, a 6 mm2 wire is enough.

I bought 100 m of 6mm2 ‘xenes’ cable from lichtex and asked them the details; they reply: Hartgezogenes Kupfer, verzinnt. Mehrdrähtiger Leiter, Klasse 5 IEC60228; bei 20 °C betraegt der Winderstand R pro Meter fuer 4mm² ca. 5.1 × 10-3 Ohm, fuer 6mm² ca. 3.2 × 10-3 Ohm.

On the flat roof, placed seven pairs of cbl used panels:

Since 7 x 4.7 = 32.9 < 40 A, the 6mm2 wire should suffice for all seven pairs.

Measuring Charger and Inverter DC Currents

The battery, chargers and inverter will generate the following maximum currents:

Cables from the charge controllers to the battery and inverter: resistance calculator says R = ca. 0.001 ohn. With a 10 A current, that should generate a voltage differential of ca. 0.01 V or 10 mV.

Using a INA121 instrumentation amplifier with a gain of 100 to monitor that would map the interval [0,20A] to [0,1V]. It supports gains between 1 and 10000.

Using Arduino Uno to measure voltage, we have six ADC input pins (A0-A5); a multiplexer feeds one of the six into the ADC. The standard setup measures voltages between 0V and 5V with a resolution of 4.9mV.

Todo: measure the precise resistance of the five individual pieces of cable.

Blocking and By-Pass Diodes

cbl used panels include three diodes each, type IR50SQ100 or 50SQ100, Vishay Semiconductors Schottky Diodes & Rectifiers 100V 5A Schottky DO-204AR. Are two of them blocking and one the bypass? If not, then we may need to add blocking diodes before hooking up all our pairs in parallel.

Nope, testing revealed that they are all three by-pass diodes, for the three strings of cells integrated in each panel. Applying a voltage across the poles of an unlighted panel sends current through it ‘backwards’. So, I added my own blocking diodes.

I bought 50 pieces Master Instrument (MIC) SR5100 Schottky diodes (datasheet). Unfortunately, they have a forward voltage drop of 0.85 V, so we loose 4.7 A x 0.85 V = 4 W of peak power from each pair of panels. Ah, I see now how the type is encoded: SR5100 stands for SR-5-100, a Schottky rectifier with a rating of 5 A and 100 V.

Semitransparent

Frage zu 50% halbtransparente lichtdurchlaessige PV-elemente, die Strom erzeugen und auch Licht durchlassen: Die koennte man ja eventuell aufs Dach machen, und auch als Fenster benutzen, oder?

Antwort: Als Dach oder Fenster wäre der Dämmwert zu schlecht, aber z.B. als Dach eines Wintergartens o.ä. Vielleicht auch fuer Dachausbau, z.b. einen unbeheizten hellen Bewegungs- und stillen Raum oben unter dem Sueddach.

Charge Controller

Illuminating YouTube videos on charging:

SOC

Monitoring the state of charge:

Otto

Otto got his charger from offgridtec; Kundenberatung + 49-8721/7786187 (Mo - Do 08 - 12 und 13 - 18 Uhr, Fr 08 - 14 Uhr). He uses a https://www.amazon.de/FCONEGY-Balance-Ladeger%C3%A4t-LCD-Balance-Ladeger%C3%A4t-Adapter/dp/B07TMYCV8R to charge all kinds of different battery types.

EPEver Tracer 3210AN

I am currently using the EPEver Tracer 3210AN, an acronym, meaning:

Documentation:

Some measured data on solar irradiation on balcony roof:

So, I need to modify the charger control settings!

Here are my initial EPever Tracer 3210AN solar charger settings for the east and south facing panels on August 30.

Settings recommended in the discussion on struggling with basic LiFePO4 settings in Epever Tracer, adapted for 24 V:

Lower values are recommended to reduce battery stress, e.g., in Epever controller 90% 20% soc charge parameter Q. Interesting note from there (adapted for 24 V):

In practice, if the resting voltage is below 25 V, it’s getting low; above a resting of 26.8 V, it’s nearly full.

2021-09-03: changed my boost duration from 120 to 180. Maybe I should lower it to 10 or even 0 instead?

Tracer RS485 Communication

Links for communicating with and controlling the EPEver Tracer:

Tracer RS485 Cable

RS485 standard:

    • 5V – orange + white
    • 5V – orange
  3. RS485 B – green + white
  4. RS485 B – blue
  5. RS485 A – blue + white
  6. RS485 A – green
  7. GND – brown + white
  8. GND – brown

I used the following pins, standard colour coding, my 4-wire cable with red wires and 1, 2 and 4 black stripes, resp.:

Atached to a chopped off half of a cable marked:

I guess UTP = unshielded twisted pair; X4P = times four pairs…

With that cable and the MacOS driver for the USB-RS485 adapter, jtracer can successfully query parameter data from the EPEver Tracer 3210AN.

Renogy Rover 40A

On 2022-02-04, I installed a Rover Li 40 Amp MPPT Solar Charge Controller for the horizontal panels:

Renogy Rover 20A

On 2022-03-10, I installed a Rover Li 20 Amp MPPT Solar Charge Controller for the south-facing panels:

Warranty registration:

Arduino Charger

Battery

Must read how to find happiness with LiFePO4 batteries; LiFePO4 charge settings cheat sheet, translated from 12 to 24 V:

Chart of voltage vs capacity for a 3.2V LiFePO4 cell and a 24V LiFePO4 battery combined from the article (above) and the graph (below), latter marked with an apostrophe ‘:

V%
3.65029.2100'-100 (charging)
3.45027.699.5'
3.40027.2100 (resting)
3.37527.099'
3.36326.996'
3.35026.890'-99
3.32526.680'-90
3.31326.565'-70
3.30026.460'-70
3.28826.355-55'
3.27526.240-50'
3.26326.140'
3.25026.030-30'
3.22525.820-25'
3.20025.617-20'
3.15025.214'
3.12525.014
3.00024.09-9.5'
2.80022.45'
2.50020.00-0'

LiFePo4 voltage charging

LiFePo4 voltage discharging

LiFePO4 8S VariCore 3.2V 200Ah

24 V system: 25.6 V battery, max charge 29.2V, min discharge 20V – 8 cells VariCore 3.2 V 200Ah 3C LiFePO4, 3.82 kg, 200 x 172 x 53 mm, working voltage 2.5-3.65 V for euro 560 – specification – akkudoktor thread on 24V DIY Batterie: neue Zellen parallel zu den alten schalten?

These cells were not good. However, I used them for the PVM system round the clock from summer 2021 until december 2024, 3.5 years. In that time, PVM generated 116 + 653 + 538 + 506 = 1813 kWh, which would cost less than eur 730 from the grid. Seeing that the battery cells + BMS alone cost about 600 euro, disregarding panels, chargers, installation etc., the ROI is definitively negative.

LiFePO4 16S EVE LF280K 3.2V 280Ah

Originally planned for a 48V system; 16 x LiFePO4 3.2V prismatic battery cells for $2227.20 incl. shipping from Docan Power, specification; standard charge and discharge is 0.5C, i.e., 140A for EVE 280Ah; 1C is 280A; the peak current is 2C, 560A.

Other Batteries

Salt Battery

Falk has built a 30 kW peak PV system. He plans to expand to 100 kW and start storing energy in salt-based batteries.

Hydropower

A possible alternative to using batteries for storing electrical energy might be storing and recuperating it with energy from hydro-power instead:

The theoretical potential energy in a volume of elevated water can be calculated

W = m g h
= ρ V g h                      (3)

where

W = energy (J)
m = mass of water (kg)
V = volume of water (m3)

Example – Energy in Elevated Water Volume

10 m3 volume of water is elevated 10 m above the turbine. The potential energy in the water volume can be calculated as

W = (1000 kg/m3) (10 m3) (9.81 m/s2) (10 m)
= 981000 J (Ws)
= 981 kJ (kWs)
= 0.27 kWh

20 m3 with 20 m height difference:

W = (1000 kg/m3) (20 m3) (9.81 m/s2) (20 m)
= 3924000 J (Ws)
= 3924 kJ (kWs)
= 1.08 kWh

That is a large volume of water for a relatively small amount of electrical energy. I guess we will stick with batteries after all.

Bidirektional

V2H is vehicle-to-home, V2G vehicle-to-grind; Vehicle-to-Grid kann die Lebensdauer von Batterien in Elektroautos verlängern.

BMS Battery Management System

I first tried a Daly Smart BMS. Initially, I could not get that to work. I then switched to ther i-tecc BMS, but that did not balance the cells, and switched off when they consequently got unbalanced. I tried to add the heltec active balancer in parallel with the i-tecc BMS, but that did not help. The second time around, I got the Daly Smart BMS to work after all. It performed more or less OK until October 2024, when it started to shut off the battery both when the sunshine was strong, charging too much, and at night, with no charge at all; apparently, it was not balancing the cells well enough. I replaced it by a JK-B2A20S20P BMS in December 2024, and all was well again.

LibreSolar Open Source BMS

Daly Smart BMS

In hindsight, Daly BMS is not recommended. It is cheap. However, it is a passive balancer. It balances the cells by burning excess energy. It was always somewhat unreliable, switching off the battery unnecessarily, often when there is too much sun, so the battery voltage hits some upper limit, or the cells drift apart when fully charged. In October 2024, it started switching off the battery at night as well, with no sun at all. I decided to replace the Daly balancer for the original 24V battery. The JK BMS active balancers are recommended in many forum discussions.

i-tecc BMS

I then switched to a more expensive 200 euro non-smart German BMS LiFePO 8S 150A 24V by i-tecc:

That worked fine right out of the box. However, there is no way to monitor it or read any data from it. Futhermore, it does nothing at all to balance the cells until the battery voltage reaches 28.8 V. I was only able to find that out by calling and asking.

Maybe it does do some balancing after all, however; on 2021-10-30, the bms turned off due to cell imbalance and cell #2 going below its minimum; ever since, they seem to be doing quite well, even though cell #2 keeps lagging behind the others; 2021-12-16, after months of use and never reaching 28 V, they appear to be almost perfectly balanced.

JK BMS 2A 20S JK-B2A20S20P

I bought a JK-B2A20S20P from AliExpress IC GOGOGO Store recommended by Andreas Schmitz for 181 euro (2022-08-12):

I originally planned to use the JK-B2A20S20P for my 48V battery, but never got around to building that. So, the BMS remained sitting unused in its pristine state until December 2024.

In December 2024, I replaced the Daly BMS on the original 8S 200Ah LifePO4 battery by JK BMS, and the battery immediately worked perfectly again with no problems whatsoever.

The JK BMS iOS app runs well on the MacBook PC:

According to the manual, the red LED is the Bluetooth connection indicator; it is always on when Bluetooth is connected to the BMS, and flashes when disconnected.

In January 2025, I removed the 200Ah Varicore battery cells, replaced them by the 280Ah EVE cells instead, and set up the JK-B2A20S20P to manage them. Funnily, the Macbook JK BMS apps is unable to log in and write to the BMS to modify the settings. I had to install the JK BMS app on an Android phone instead. The Macbook app is still fine for reading the values, though.

JK BMS 2A 8S JK-B2A8S20P

In October 2024, I decided to replace the Daly passive balancer for the original 24V battery.

I ordered an active BMS JK-B2A8S20P from the HankzorBMS Store on AliExpress for EUR 70; Hankzor is recommended in the diysolarforum:

In January 2025, I passed this 8S JK BMS on to Rene, together with 8 of my 280Ah LiFePO4 cells.

Balancer

A discussion on using an active balancer with Daly BMS explains the cell quality and the concepts and uses of active versus passive balancing. If you stay in the middle (flat) part of the voltage curve and avoid discharging below the knee at ca. 15% SOC, the BMS passive balancer should be able to handle the cell balancing with no need for an additional active balancer.

Heltec Active Balancer

The i-tecc BMS does not start actively balancing until the battery reaches 28.8 V, i.e., 3.51 V per cell. Unfortunately, that has never happened yet. I therefore purchased an additional 55 euro active LTO/LiFePo4/NCM balancer by Heltec BMS providing 8S 5A capacitive active equalization from LTO-Store, Andreas Petermann, Neuffen, tel. + 49-1520/8767231:

Capacitive active energy transfer equalization board (high precision 5mv, whole set of equalization, not adjacent equalization) Working voltage 2.7V-4.5V, suitable for ternary lithium, lithium iron phosphate, lithium titanate. Working principle: the capacitor fit transfers the charge carrier, and the balancing work is started when the balancing board is connected to the battery. The original brand new ultra-low internal resistance MOS, 2OZ copper thick PCB, balancing current 0-5.5A, the more the balancing current, the smaller the battery. Reserve the wiring position of the dormant switch, the operating current in dormant power-off mode is less than 0.1mA, and the equilibrium voltage accuracy is within 5mv. The quiescent current is about 12 mA; it is recommended that the battery capacity should be suitable for batteries with 60-300Ah. With under-voltage sleep protection, voltage below 3.0V will automatically stop entering the sleep state; standby power consumption is less than 0.1 mA. Specifications

Inverter

Neutral Ground Bonding

Some inverters do not implement a neutral ground bonding, cf., how does your inverter deal with ground. In my case, I have 220V between the two inverter AC power output lines, but neither of them is neutral ground. Compared with ground, one has 90V and the other 130V. I have a RCCB (FI-Schalter) installed, and that is not triggered. So be aware! There are no ‘neutral’ and ‘phase’ lines; both AC power lines are ‘hot’.

The neutral and ground wires should be “bonded” together at the main panel only, cf., understanding neutral, ground, grounding, and bonding.

Inverter earthing and N-G Bonding in a simple off-grid setup discusses neutral ground bonding and also the difference between high-frequency and low-frequency inverters; mine is a high-frequency, and a low-frequency inverter would be better. For the concrete wiring, refer to the video on off-grid inverter consumer unit grounding:

Neutral ground bonding

Victron Phoenix

I temporarily hooked up an old used Victron Phoenix inverter: Manual for Phoenix Inverter Compact 1200 and 1600.

Bad news: Data communication with Victron Energy products says that the victron inverter communicates using VE.Bus and nothing else. “VE.Bus is our proprietary protocol used by the Inverters to synchronize their AC outputs. There are VE.Bus communication ports on our Inverters, Multi’s and Quattro’s. The synchronization feature is mission-critical. Direct third-party connections are not allowed. All interfacing has to be done via Modbus TCP (preferred), “VE.Bus to CANbus/NMEA2000 interface”, or via the MK2/MK3”. To obtain official Modbus TCP requires a victron color control gx device, which costs around eur 500 on ebay. so, i would say, forget it. i see no realistic way to hook up these inverters or communicate with them at all.

Good news: Connecting your Victron product to a computer with VE Configure says that VE configure II is a program used to configure settings/options on a Multi or Quattro, connecting your Victron product to a computer and that Phoenix Chargers, Phoenix Multi (including Compact) and larger Phoenix Inverters are all compatible with VE configure. All other models are not. So, maybe it is possible to configure and control the Phoenix after all.

Easun Power

Easun Power Official Store pure sine wave inverter DC 24V AC 220V 2500W inverter with LED display

I wrecked this one by attaching PV panels directly to the inverter. That worked fine as long as the battery was happy. At oner point, though, the BMS turned it off, the voltage rose too high, and the inverter was destroyed.

PUGU

PUGU 2500W/5000W reiner sinus Spannungswandler Wechselrichter 24V 230V Inverter mit USB for eur 186 mit 5 Jahre Garantie.

MPP Solar PIP8048MAX Charger-Inverter

8 kW PIP8048MAX from MPP Solar, tel 010017-00886.2.8797.8896. ordered per email to sales@mppsolar.com.

Specifications:

Hybrid Inverter

Balkonkraftwerk anmelden oder nicht, vgl. ComputerBild – Meldepflicht von Stecker-Solaranlagen – Balkonkraftwerk ohne Anmeldung betreiben: Welche Folgen das haben kann.

Nicht Anmelden gilt als Ordnungswidrigkeit und kann laut Energiewirtschaftsgesetz eine Geldbusse nach sich ziehen. Bislang ist ein solcher Fall aber nicht bekannt.

GMI Grid Tie MPPT Microinverter

I bought a GMI 600W DC 18-50V grid tie MPPT micro inverter for 86 Euro:

I hooked it up with the Trina panel (375 Wp) on a sunny and slightly hazy February afternoon and it produced between 80 and 120W AC power. Trina produces max 11A at 34Vmp, so I could add 5 of the Wuerth panels (34Vmp, 2.4A max, 12A from five of them) in parallel to the Trina panel. Or I could populate it with 10 Wuerth panels and use the Trina elsewhere, maybe on the south-facing balcony roof, with a new dedicated 24V charger. 10 Wuerth panels can be placed in a rectangle of 6 x 1.2 or 3 x 2.4 metres.

It stopped working after a few hours, and I was unable to diagnose any problem, so I returned it again.

Replus 250 Microinverter

In March 2023, I bought four Renesola Replus-250 micro inverters from ebay Kleinanzeigen, 4 x Wechselrichter für ein Balkonkraftwerk Replus 250, for 60 euro incl. delivery:

Operating Instructions: The Replus-250 is powered on when sufficient DC voltage from the module is applied. The status LED will start flashing as an indication that it is live:

  • Standby: LED flashes on 2 seconds and off 2 seconds
  • Producing power: LED flashes on 1 second and off 1 second
  • Producing power and communicating with MRG: LED flashes on 0.5 seconds and off 0.5 seconds

One Replus 250 could be attached to three (or four?) Wuerth panels in parallel. They would deliver max. 225 W (3 x 75), 7.2 A (3 x 2.4), 43 V, taking 1830 x 1205 mm space (3 x 605).

The south balcony roof provides 3000 x 1275 mm and could take four Wuerth panels easily, or even five at a pinch, feeding two Replus 250. The rectangle above bathroom dormer facing east has 4.1 x 1.4 m. We can place three Wuerth with one Replus on the balcony roof, 1.85 x 1.2, and 6 Wuerth + 2 Replus on the rectangle above the flat-roof dormer, 3.66 x 1.2.

AC connector plug: Wieland Steckverbinder RST25I3S B1 ZR2SV BG03, available on ebay for eur 10, dust- and waterproof according to IP67 IP code.

By the way, I happened to learn that an improvement over standard 1-phase microinverters might be possible with a three-phase grid-connected microinverter for AC photovoltaic module applications.

SG300W Microinverter

Similar to NETek SG300MS, SG = solar grid, 300W, M = medium operating voltage 18V-50V, MPPT voltage 24V-40V, S = single MC4 connector pair, cf. NETSGPClient).

On 2024-01-22, I bought three RundeGestz Micro Solar Inverter SG300W for eur 64 per piece: 300W Mikroinverter fuer Balkonkraftwerk Wifi WLAN MPPT to implement PVS and cover the wood stacks on the H30 south border with PV and balkonkraftwerk: 5.4 x 2.4 meter using 12 of the remaining wuerth panels, 4 panels a 75W each for each of the three inverters, connecting the three sets to the three phases of the south side drehstrom.

Absaar AB800A Microinverter

Absaar AB800A microinverter:

NEP BDM-800 Microinverter

NEP BDM-800

DC Input

AC Output

Efficiency

General Data

Zaehlerschrank

Was ist eHZ zählerschrank? – elektronische Haushaltszähler

Komplett ausgestattet sehe ich in Internet Preise zwischen 500 und 1200 euro.

Erdung muss sein. Auch die Montageschienen auf dem Dach muessen alle miteinander verbunden und geerdet werden; dazu muss ein Erdungskabel (16 mm2) an der Unterkonstruktion angeschlossen und mit einer sicheren Erdung verbunden werden.

Ueberspannungsschutz, SPD, surge protection device:

Switch Between Solar and Grid Main

Monitoring

Here is an initial monitoring plan 2021-10-29:

The first article above looks very promising to achieve some of this.

Hall-Effect Current Measurement

Currently planning to measure the DC PV panel input, charger output and inverter input currents using a 30A Hall-effeet sensor module ACS712ELC 30A for Arduino:

Control Inverter from BMS

Switch Surplus to Heat Pump

How can I drive the hot water heat pump with surplus solar energy from the PV when the battery is full?

Thinking about an Arduino Voltage Controlled Relay.

Question: Wenn ich richtig verstanden habe, dann hast du drei Laderegler und eine Lithium Eisenphosphat Batterie mit 4,8 kWh mit 24V

Deine Solarregler haben vermutlich intern Blocking Dioden (zumindest am Batt + - Anschluss), sonst wurde sich die Batterie bei Dunkelheit entladen, oder es hätte Rauch gegeben bei der Parallel-Schaltung J. Auf jeden Fall sollten die Laderegler jeweils eigene Kabel haben und erst direkt an der Batterie zusammengeschaltet sein!

Eventuell kann man den Strom messen über die Verbindungskabel zur Batterie als Shunt. Dazu folgende Fragen:

Wenn das nicht reicht könnte man auch einen Shunt Widerstand in jede Plus-Ladeleitung setzen, z.B. 5W Metall 0,1 Drahtwiderstand, axial, 5 W, 100 mOhm, 1%, und mit dem Arduino die Spannungen 3x vor den Shunts und 1x am Pluspol der Batterie über einen Spannungsteiler messen. Um ein halbwegs genaues Ergebnis zu bekommen, müsste man eine Vergleichsmessung von Hand vornehmen, dann kann man das Arduino Ergebnis abgleichen.

Dann könnte man mit überschaubarem Aufwand mit einem Arduino folgendes machen:

Dann hat sich zumindest der Ladestand der Batterie nicht verschlechtert

Man könnte als Erweiterung dann auch grob den Ertrag über die Zeit ermitteln und z.B. über eine Schnittstelle ausgeben. (Genauigkeit abhängig von Shunt, Spannungsteiler Toleranzen und AD-Wandler Auflösung).

Answer: Also, die drei laderegler haben drei getrennte kabel zu einem gemeinsamen treffpunkt, und von dort geht es auch (via die bms) an die batterie.

Ich schaetze, dass die drei kabel in sich alleine schon genuegend widerstand haben, um sie als shunt nutzen zu koennen, den minimalen spannungsabfall zu messen, und daraus den strom errechnen zu koennen. Weil ich mir damals schon so was dachte, habe ich folgendes erforscht:

die laengen der kabel von laderegler zur batterie und auch zum inverter sind recht minimal gehalten und variieren deswegen je nach montage, siehe angehaengtes bild 2023-03-22_chargers_battery_inverter_cables.jpg. die drei kabel im vordergrund sind die minus-kabel. Das bms haengt am minus-pol. Die plus-kabel sind mit roten klebstreifen markiert, oder sind ganz rot. Die meisten kabel zum den PV-panelen haben glaube ich 6 mm^2 querschnitt. die kabel von batterie zum inverter sind so fett wie ich kriegen konnte. Die sollen ja bis zu 2500 W aushalten koennen, also 100A. Das kabel vom grossen rover hat max. 40A zu uebertragen. Genaue querschnitte weiss ich nicht mehr. Alle drei laderegler teilen immer mit, wieviel strom sie gerade produzieren. Das koennte man zur groben kalibrierung nutzen.

Mit dieser vorgehensweise fehlt dann auch nicht mehr viel, um den finalen schritt zu gehen:

Ich habe soeben im datenblatt der WP nachgeschaut, was sie genau braucht: 425 W, 1.84 A bei 230 V. Die jaehrliche leistungsaufnahme haengt von der eintrittslufttemperatur ab und schwankt zwischen 1345 kWh bei 2 grad, 1069 kWh bei 14 grad und 1014 kWh bei 20 grad. Ich hole luft aus dem treppenhaus. Die hatte im vergangenen winter fast immer mindestens 16 grad. Wird sich natuerlich abkuehlen durch die WP. 1300 kWh / 365 Tage ergibt 3.5 kWh pro tag. Das ist aber fuer 300 Liter wasser oder mehr. Unser taeglicher verbrauch fuer 6 personen liegt bei ca. 150 liter/tag. Also muessten weniger als 2 kWh pro tag reichen, also 4 stunden sonne bei 425 W. bloederweise habe ich bei der PV-anlage mehr als 450 W zu verpulvern.

Daher waere es vielleicht optimal, nicht sofort zuerst ausschliesslich die batterie vollzuladen, sondern doch versuchen, gleich morgens frueh beides parallel anzutreiben, wenn genuegend sonne da ist.

Die batterie wird im sommer im laufe des tages auch dann voll, wenn die sonne nicht scheint. Nicht nur im sommer, sondern schon ab anfang februar.

Einspeisung

Direktvermarktung PV-Strom:

Foerderung

KfW-Bundesland Baden-Württemberg is running a Förderprogramm Netzdienliche Photovoltaik-Batteriespeicher supporting Stromspeicher in Verbindung mit neuer Photovoltaikanlage with a Zuschuss of 200 Euro pro kWh Speicherkapazität. Allerdings:

Aufgrund der hohen Nachfrage sind die Fördermittel leider erschöpft. Es können deshalb keine neuen Anträge mehr gestellt werden.

Our 24V battery stores 200 Ah or ca. 24 * 0.2 = 12 kWh, so we could have asked for 2400 Euro Zuschuss.

Battery Charge vs Consumption

Measurements comparing battery charge state with the kWh consumed in the 220 V AC circuit. Battery loss versus gain over day and power consumption over night:

date timeESVkWhhΔVkWh
2021-07-16 18:0013.732.8
2021-07-17 08:0012.933.1140.80.3
2021-07-17 17:5014.333.5
2021-07-18 06:3012.834.0131.50.5
2021-07-18 20:2012.934.5
2021-07-19 08:2012.835.0120.10.5
2021-07-19 20:200.059.913.035.5
2021-07-20 08:000.059.912.935.9120.10.4
2021-07-20 14:000.860.214.236.2
2021-07-20 20:200.860.413.136.5
2021-07-21 07:200.860.412.836.9110.30.4

Starting 2021-07-19 after installing the second charger for the roof ridge panels, I also added the total kWh produced by the two chargers attached to the four roof ridge panels facing east UE and the four balcony roof ones facing south US and started monitoring power generation and consumption from one morning to the next; UE, US, ΔE, ΔS and consumption C are in kWh per 24h.

date time UE US VkWh ΔEΔSC
2021-07-17 08:0012.933.1
2021-07-18 06:3012.834.0 0.9
2021-07-19 08:2012.835.0 1.0
2021-07-20 08:000.059.912.935.9 0.9
2021-07-21 07:200.860.412.836.9 0.80.51.0
2021-07-22 12:402.861.014.238.3
2021-07-22 20:103.161.113.138.7
2021-07-23 06:203.161.112.939.0 1.10.31.0
2021-07-24 08:004.261.412.840.1 1.10.31.1
2021-07-24 18:304.662.214.240.6
2021-07-24 23:404.662.212.841.2
2021-07-25 06:404.662.212.1off
2021-07-25 10:404.662.212.4off

ΔE is larger than ΔS. There may be several reasons for this: E probably receives more sun than S, since S is shadowed by the walnut tree. Also, E may already generate enough power to almost fully charge the battery, so S cannot add that much more afterwards.

Set up the 24 V system with new battery and new inverter on August 30; added voltage and amperage readings from different devices VE, AE, VS, AS, inverter VI and voltmeter on battery poles VB:

date time VE AE UE VS AS US VI VB kWh ΔE ΔS C
2021-08-30 15:00 9.1 67.1 27.3 44.8
2021-08-30 18:00 9.1 67.3 27.3 44.9
2021-08-31 06:40 BMS blocked
2021-08-31 08:40 9.1 67.3 26.4 45.4
2021-08-31 20:40 9.5 68.1 26.5 46.1 0.4 0.8 1.2
2021-09-01 08:20 9.5 68.1 26.4 46.6
2021-09-01 21:40 10.3 68.8 26.5 47.3 0.8 0.7 1.2
2021-09-01 23:10 BMS blocked
2021-09-02 09:30 Fixed loose BMS C8+ sensor
2021-09-02 09:30 10.3 68.8 26.5 83.9
2021-09-02 20:10 10.9 69.0 26.6 84.3
2021-09-03 09:00 10.9 69.0 26.3 84.9
2021-09-03 10:00 26.4 11.0 26.3 69.0 26.5 25.8 85.0
2021-09-03 12:10 27.1 7.7 11.5 27.1 8.6 69.1 27.2 26.5 85.1
2021-09-03 14:50 11.5 28.2 11.6 69.5 27.3 26.6 85.3
2021-09-03 15:00 27.2 -0.1 11.5 27.3 0.0 69.5 27.3 27.0 85.3
2021-09-03 16:40 28.1 0.1 11.8 27.3 0.0 69.6 27.3 27.0 85.3
2021-09-03 16:50 27.4 -0.1 11.8 27.3 0.0 69.6 27.3 26.6 85.4
2021-09-03 20:10 26.4 -0.1 11.8 26.4 0.0 69.7 26.5 25.9 85.6 0.9 0.7 1.3
2021-09-03 22:20 26.4 -0.1 11.8 26.3 0.0 69.7 26.5 25.9 85.9 0.9 0.7 1.7
2021-09-04 09:10 26.3 + 0.1 11.8 26.2 0.2 69.7 26.4 25.7 86.3
2021-09-04 13:30 27.3 + 7.1 12.6 27.3 11.7 70.1 27.3 26.6 86.5
2021-09-04 15:30 27.1 -0.1 12.7 27.4 0.0 70.3 27.5 26.7 86.6
2021-09-05 09:00 26.4 + 0.1 12.7 26.3 0.1 70.4 26.4 25.8 87.2
2021-09-05 13:00 27.9 + 3.2 13.4 27.9 11.2 70.7 28.3 27.4 87.4
2021-09-05 16:10 27.6 -0.1 13.4 27.4 0.0 70.8 27.5 26.9 87.5
2021-09-05 21:00 26.4 -0.1 13.4 26.3 0.0 70.9 26.5 25.8 87.8
2021-09-06 07:30 26.3 -0.1 13.4 26.3 0.0 70.9 26.4 25.8 88.3
2021-09-06 12:40 27.4 + 8.1 14.0 27.4 10.8 71.0 27.5 26.7 88.5
2021-09-06 17:20 27.9 + 0.1 14.2 27.9 5.0 71.5 28.0 27.4 88.8
2021-09-06 19:30 26.5 + 0.0 14.2 26.4 0.0 71.6 26.6 25.9 88.9
2021-09-06 21:00 26.5 -0.0 14.2 26.4 0.0 71.6 26.6 25.9 89.0
2021-09-07 09:10 26.5 + 0.2 14.2 26.4 0.3 71.6 26.6 25.9 89.5
2021-09-07 13:40 27.5 + 6.8 14.9 27.5 11.3 72.1 27.6 26.8 89.5
2021-09-07 17:40 26.9 + 0.1 14.9 26.8 0.9 72.3 26.9 26.3 90.0
2021-09-08 06:50 26.5 -0.1 15.0 26.4 0.0 72.3 26.6 26.3 90.5
2021-09-08 12:00 27.1 + 8.3 15.3 26.9 1.3 72.4 27.0 26.4 90.8
2021-09-08 20:20 26.5 -0.1 15.7 25.9 0.0 72.9 26.6 26.4 91.1
2021-09-09 08:00 26.4 + 0.0 15.7 26.3 0.2 72.9 26.5 25.8 91.7
2021-09-09 10:00 26.6 + 5.5 15.8 26.5 0.4 73.0 26.7 26.0 91.9
2021-09-09 12:20 27.0 + 3.4 16.1 27.0 4.4 73.0 27.2 26.6 92.0
2021-09-09 20:30 26.5 -0.1 16.5 26.4 0.0 73.7 26.6 26.2 92.3
2021-09-10 08:10 26.5 0.0 16.5 26.4 0.1 73.7 26.5 26.2 92.8
2021-09-10 12:20 27.0 4.6 16.7 27.0 5.9 73.9 27.1 26.7 93.2
2021-09-10 22:40 27.0 0.0 17.0 27.0 0.0 74.4 26.5 26.2 93.9
2021-09-11 08:30 26.4 0.2 17.0 26.4 0.3 74.4 26.5 26.1 94.3
2021-09-11 12:50 26.8 3.0 17.3 26.7 3.9 74.6 26.8 26.4 94.7
2021-09-11 21:50 25.3 0.1 17.4 25.2 0.0 75.2 26.4 95.3
2021-09-12 09:20 25.2 0.1 17.4 25.2 0.1 75.2 26.3 95.8
2021-09-12 11:00 26.6 8.7 17.5 26.5 0.2 75.2 26.5 26.2 95.9
2021-09-12 12:20 26.9 3.5 17.8 26.7 3.7 75.7 26.8 26.4 96.0
2021-09-12 16:30 27.4 1.2 18.5 27.4 11.8 76.6 26.8 27.1 96.2
2021-09-13 08:00 0.0 18.5 25.4 0.0 76.7 25.3 25.2 96.8
2021-09-13 12:40 27.4 8.0 19.0 27.3 10.8 76.8 27.4 26.9 97.0
2021-09-13 16:20 27.2 -0.1 19.3 27.5 0.0 77.3 27.3 27.3 97.3
2021-09-13 22:10 26.5 -0.1 19.3 26.4 0.0 77.4 26.6 26.2 97.6
2021-09-14 08:10 26.5 + 0.1 19.3 26.4 0.1 77.4 26.6 26.2 97.9
2021-09-14 11:00 26.5 + 3.4 19.4 26.4 0.5 77.4 26.6 26.2 98.3
2021-09-14 12:10 27.0 + 8.1 19.5 26.9 2.8 77.4 26.9 26.6 98.4
2021-09-14 22:20 26.4 -0.1 19.9 26.3 0.0 77.9 26.4 26.1 98.8
2021-09-15 11:40 26.4 + 0.1 19.9 26.3 0.2 77.9 26.5 26.1 99.5
2021-09-15 20:00 26.1 -0.1 20.0 26.0 0.0 78.1 26.2 25.8 100.0
2021-09-16 15:20 26.8 + 3.6 20.3 26.8 11.0 78.8 26.9 26.4 101.1
2021-09-16 20:10 26.3 -0.1 20.4 26.2 0.0 79.3 26.3 26.0 101.4
2021-09-17 08:50 26.0 0.1 20.4 25.9 0.2 79.3 26.0 25.7 101.9
2021-09-17 12:00 27.0 8.1 20.8 26.9 5.4 79.4 27.0 26.7 102.1
2021-09-18 09:20 26.4 0.1 21.4 26.3 0.1 80.9 26.5 26.1 102.9
2021-09-18 15:50 27.7 -0.1 22.2 27.6 3.8 81.8 27.7 26.1 103.2
2021-09-18 19:50 26.6 -0.1 22.2 26.5 0.0 81.9 27.6 26.3 103.4
2021-09-19 09:30 26.4 0.0 22.2 26.3 0.1 81.9 26.4 26.1 104.2
2021-09-19 21:50 26.1 0.0 22.3 26.0 0.1 81.9 26.1 25.8 104.7
2021-09-20 11:50 26.3 0.4 22.3 26.3 1.8 82.0 26.4 26.0 105.3
2021-09-20 22:20 25.9 -0.0 22.5 25.8 0.0 82.5 25.9 25.6 106.0
2021-09-21 09:00 25.9 -0.0 22.5 25.8 0.1 82.5 25.9 25.8 106.3
2021-09-21 19:50 26.1 -0.1 23.0 26.0 0.0 83.7 26.2 25.9 106.9
2021-09-22 21:00 26.4 -0.1 23.9 26.3 0.0 85.0 26.4 25.9 108.2
2021-09-23 09:20 26.1 0.0 23.9 26.0 0.1 85.0 26.2 25.8 108.6
2021-09-23 12:50 27.3 8.0 24.4 27.2 11.2 85.3 27.2 26.8 108.7
2021-09-24 08:10 26.5 -0.1 24.8 26.4 0.0 86.5 26.5 26.2 109.5
2021-09-24 11:50 27.2 8.6 25.1 27.1 4.6 86.5 27.2 26.9 109.8
2021-09-27 09:50 26.3 0.1 26.3 26.3 0.2 88.4 26.4 26.1 112.5
2021-10-02 12:40 27.0 3.8 29.0 26.9 5.1 91.9 27.0 26.6 116.6
2021-10-03 21:50 25.9 0.0 29.4 25.8 0.0 92.6 25.9 25.6 118.9
2021-10-04 08:20 25.7 119.5
2021-10-05 19:10 25.7 0.0 29.4 25.7 0.0 92.7 25.7 25.4 119.9
36-day total 20.3 25.6 38.5
1-day average 0.56 0.71 1.07

While the battery was blocked in the night between September 1-2, the consumption meter jumped from 47.3 to 83.9 kWh, so deduct 36.6 from the total consumption.

The sun shone almost uninterrupted every day all day September 1-5, so the batteries should reach 100% SOC (or whatever maximum charge is desired) if everything is working correctly.

September 3: With the chargers charging slightly at 10 o’clock in the morning, producing 0.1-0.2 A each, the different devices, chargers S, E, inverter I and voltmeter on battery poles B report the following voltages:

date time E S I B
2021-09-03 10:00 26.4 26.3 26.5 25.8

On September 3 just before three in the afternoon, VE and AE, VS dropped from 28.2 · 11.6 down to 27.3 · 0.0 within a minute or so. Why? Was that the switch from boost charging to float charging? Should I raise the boost charging time to increate the battery state of charge SOC?

Later the same day, just before five, VS and AS dropped from 28.2 · + 0.1 down to 27.4 · -0.1; also to stop charging because a limit was hit, I assume.

The battery pole voltage is still just 26.6 as soon as charging has stopped.

I raised the boost duration from 120 to 180. I want to raise the battery ‘fully charged’ level up to 28 V at least, preferably 29. On the other hand, a resting voltage below 25 V is getting low and above 26.8 V is nearly full. So, maybe I am in a pretty good window now.

In the evening of September 3, we watched TV and consumed 0.4 kWh. The battery pole voltage remained unchanged at 25.9 V, so all seems to be well.

2021-09-06: During the night, the battery lost 0.1 V going from 25.9 to 25.8 to give out 0.8 kWh; pretty good going.

2021-09-06: Raised float charging voltage from 27.6 to 28, and boost reconnect charging voltage from 26.4 to 26.8 V, trying to achieve a resting battery pole voltage in the evening and night above 26 V. So far, the BMS has always shown at least 0.6 V higher voltage to the charger than the battery pole voltage.

2021-09-06: Watched the float charging video and modified the float charging voltage to equal the absorbtion or boost one, setting both to 29 V. Raised the boost charge reconnect voltage to 27 V, Also reduced the equalisation duration to zero; it should be disabled anyway: east, south.

2021-09-07: i-tecc says about the BMS:
Q: Egal ob tagsueber geladen + verbraucht wird oder nachts nur verbraucht ist Vp immer etwas hoeher als Vb, um ca. 0.6 bis 0.9 V. Ist das normal?
A: Nein. Es könnte ein Anschlussfehler vorliegen oder die Verbindung nicht richtig sitzen. Wir würden empfehlen zu untersuchen, woher die Differenz kommt.
Q: Ich will gerne die batterie bis ca. 27 V volladen. Ich will sie gar nicht bis zur grenze von 29.2 vollpumpen. Ich habe gelesen, dass die batterie schon bei 26.8 V als fast voll betrachtet werden kann.
A: Die Ladeschlussspannung liegt bei 28.8V. 29.2V wäre zu hoch, alles unter 28.8V ist zu niedrig, um ein ausgeglichenes System zu erhalten. Sie brauchen die 3.6V pro Einzelzelle, damit der Balancer arbeiten kann. Sie können gerne ab und zu die Batterie nur mit 27V laden, allerdings sollten die 28.8V auch regelmässig erreicht werden, gerade in der Anfangsphase/Initialladung.

So, I upped the charger boost and float charging voltages from 29 to 29.5 V to hopefully ensure the battery pole voltages reach 28.8 soon: east, south. This forced me to raise the charging limit voltage to a higher value; I picked 29.6 V for that.

2021-09-08: One little puzzle solved: my digital voltmeter reports 0.6 V less than the inverter readout, so the observed difference so far between battery minus and BMS minus poles is actually and always has been non-existant. So, I am assuming that VB is the more accurate measurement, and all the others are too high.

Some success raising the SOC: for the first time, the battery pole voltage is over 26 V in the early morning, before charging starts.

2021-09-13: at 16:25, the battery voltage is 27.3 and the south panels are in full sunshine. Yet, the charger reports zero ampere charging current. Apparently, it has switched off. Why? Did it possibly switch off because the bulk charging time is limited to 180 minutes?

2021-09-14: epever provided new recommended settings, so i updated east and south.

2021-10-02: returned from a week’s absence in ticino, battery full, over 26.6 V. used lots ofg power for lightin, broken pc screen, everythin pluged in all the time.

2021-10-04: rained all day yesterday and today, no sunshoine, battery rather low, under 25 V, lights started flickering, turning on and off. cbl turned off the inverter. in the evening, i turned it on again. after a while, the bms switched off, probably due to unbalanced cells. the battery was at 24.4 V, i think. we switched to mains electricity and took down the battery to charge it above 28.8 for the bms to balance the cells. solar pause.

2021-10-20: charging the entire chain of cells failed due to imbalanced cells, the bms blocks. total voltage 26.2 V, individual cell voltages:

  1. 3.29
  2. 3.27
  3. 3.29
  4. 3.29
  5. 3.29
  6. 3.29
  7. 3.29
  8. 3.29

Started charging cell 2 with 3.3 V at 1 A at 2021-10-20 12:50. It only took half an hour or so to et it up to 3.29 V.

Added luster terminals to enable charging individual cells.

Attached the battery to the chargers and inverter again.

date time UE AE US AS VI VB kWh ΔE ΔS C
2021-10-20 17:40 29.4 -0.1 92.7 0.1 26.7 26.2 120.1
2021-10-21 08:50 29.4 0.0 92.7 0.2 26.4 25.9 120.8
2021-10-21 12:10 29.5 0.6 92.8 4.0 26.8 26.1 121.0
2021-10-21 23:10 29.7 0.0 93.6 0.0 26.4 25.8 121.4
2021-10-22 11:50 29.7 0.3 93.6 0.5 26.4 25.7 121.9
2021-10-22 24:00 30.2 0.0 95.0 0.0 26.5 25.8 123.2
2021-10-23 08:00 30.2 0.0 95.0 0.0 26.3 25.6 123.5
2021-10-23 12:00 30.4 8.0 95.1 8.5 26.9 26.2 123.9
2021-10-24 09:30 30.9 0.0 96.4 0.0 26.4 25.7 124.8
2021-10-24 12:10 31.1 8.3 96.5 9.2 27.1 26.4 125.1
2021-10-24 14:00 31.5 5.6 97.1 12.5 27.3 26.5 125.3
2021-10-24 22:30 31.6 0.0 97.5 0.0 26.5 25.8 125.8
2021-10-25 09:00 31.6 0.1 97.5 0.0 26.4 25.7 126.2
2021-10-25 13:50 32.1 5.6 98.1 11.5 27.2 26.4 126.7
2021-10-25 17:40 32.2 0.0 98.5 0.1 26.6 25.9 126.9
2021-10-26 08:40 32.2 0.1 98.5 0.1 26.2 25.6 128.1
2021-10-27 07:50 32.4 0.0 98.9 0.0 25.8 25.2 130.0
2021-10-27 16:10 33.0 0.0 100 9.1 26.7 26.0 130.7
2021-10-27 18:30 33.0 0.0 100 0.0 26.3 25.6 130.8
2021-10-28 08:00 33.0 0.0 100 0.0 25.7 25.3 131.7
2021-10-28 12:20 33.3 7.3 101 10.0 26.5 25.8 132.2
2021-10-28 14:20 33.6 4.6 101 12.3 26.8 26.1 132.3
2021-10-28 16:10 33.7 0.1 102 9.1 26.8 26.0 132.4
2021-10-28 20:00 33.7 0.0 102 0.0 26.2 25.5 132.7
2021-10-29 11:30 33.7 0.9 102 1.9 25.9 25.2 133.7
2021-10-29 12:30 33.9 6.7 102 9.2 26.6 25.9 133.8
2021-10-29 14:10 34.2 4.6 103 11.8 26.8 26.1 133.9
2021-10-29 18:00 34.3 0.0 103 0.0 26.3 25.8 134.3
2021-10-30 08:00 34.3 0.0 103 0.0 – 25.0 –

2021-10-30 08:00: the central heating was running all night. battery cells unbalanced again, and the bms started flickering on and off. total voltage 25.0 V. individual cell voltages:

  1. 3.18
  2. 2.65
  3. 3.18
  4. 3.17
  5. 3.22
  6. 3.22
  7. 3.24
  8. 3.23

2021-10-31 20:30: after two day with no load, the battery is back up to 26.1 V, and all cells appear balanced at 3.27 V.

2021-11-02 20:30, 2021-11-03 17:30, 2021-11-05 12:00: two + three more days with no load and little sunshine: 26.3 V, cells unbalanced at:

  1. 3.29 3.30 3.32
  2. 3.27 3.27 3.27
  3. 3.28 3.28 3.32
  4. 3.28 3.28 3.32
  5. 3.31 3.31 3.34
  6. 3.31 3.31 3.34
  7. 3.31 3.31 3.34
  8. 3.31 3.31 3.34

Strange… two blocks of four, it seems…

2021-11-06 08:00 bms: shut off again with inverter saying 25.3 V, presumably due to imbalanced cells. anette was viting last night and sr=tayed the night and probably left her laptop plugged in, using more than expected.

2021-11-12 17:50: several foggy days. i switched to mains overnight, or as soon as the inverter showed less than 26 V, corresponding to about 25.3 V, measured by voltmeter on the battery. the battery continued charging, but very slowly, of course. in the week nov. 5-12, the chargers report 2 + 5 = 7 kWh net gain, the consumption is 4.4 kWh, and the battery voltage rose from 25.4 to 24.7 V. does that 0.3 V rise correspond to 2.6 kWh more energy stored? or do we need to take a large loss of energy into account, consumed energy being much less than the energy produced by the chargers? 19:30: battery voltage is down to 26.0 V and 25.4 V, resp., and consumption up to 142.1, so only 0.2 kWh. so it seems that the charger report uch more power produced than we actually consume: 7 versus 4.6 kWh, 66% or only ca. efficiency.

2021-11-18: turned it on again on a sunny day after a series of very cloudy ones. the battery was almost as low as when i stopped using solar power, even though the chargers report having generated some energy in the meantime. turned it off again in the evening at 19:30.

2021-11-19: turned it on again at 08:40 for another sunny day.

2021-11-20 15:40 in full sunshine: the inverter battery voltage 27.7 V, 26.7 at the bms battery poles, both panels were in full sunshine, east panels 80 V, south 91, yet both of them charging 0 A. why do they both stop charging at a voltage below 28 V?

2021-11-21 17:40 turned off solar again after a completely foggy day with zero input. we lasted only 24 hours, even though the battery was so full yesterday that the charger stopped charging. we used only 1.2 kWh during that time… where are the 4.8 kWh that the battery is theoretically able to store?

2021-11-23 21:40 the sun shone quite a lot today, and i switched from mains back to solar quite early in the morning.

i compared my voltmeter with cbl. mine seems to be consistently showing too low values, so all the VB measurements so far are wrong, too low, and the VI ones are correct.

2021-11-29 10:10 cbl turned off solar power last week wednesday ro thursday and the sun was away for several days. today, and i switched from mains back to solar. VB was 25.9 before turning on the inverter, 25.5 afterwards.

2021-12-02 18:20 been raining nonstop for a couple of days, inverter switched off. starting to hook up cbl used panels directly to the battery. measured the cells to check and potentially balance the bad one.

2021-12-03 10:40 sun is shining, finally switched from mains to pv again.

2021-12-15 Started attaching cbl used PV panels directly to the battery, in pairs, each providing 230 Wp, 4.7 A short circuit, 65.4 V open circuit, limited by the battery + BMS + inverter to 29 V, so they will never be able to provide more than max. 130 W per pair…

Monitoring individual cells; voltages until november were measured with my faulty voltmeter reporting too low values; from december onwards using cbl voltmeter; oh no, it does not measure with any precision below 0.1 V, so it makes little sense in this range:

Meter Readings 2022

2022-01-05 After disconneting the burned inverter and having no load for a while, the battery ought to be full, and over 28.8 V, and the BMS ought to be actively balancing.

date time12345678notes
2021-10-30 08:003.182.653.183.173.223.223.243.23bms turned off
2021-10-31 20:303.273.273.273.273.273.273.273.27after 2 days charging with no load
2021-11-02 20:303.293.273.283.283.313.313.313.31cell 2 lags, cells 4-8 are ahead
2021-11-03 17:303.303.273.283.283.313.313.313.31
2021-11-05 12:003.323.273.323.323.343.343.343.34during charging ca. 5 A
2021-12-02 18:203.253.193.243.213.273.273.273.26not charging
2021-12-16 17:203.213.203.203.203.213.213.213.21not charging
2021-12-16 19:203.203.183.203.203.203.203.203.20after consuming ca. 0.3 kWh
2021-12-16 21:003.203.163.193.183.203.203.203.20after consuming ca. 0.5 kWh
2022-01-05 14:003.323.323.323.323.773.773.643.33bms stops charging further at 27.7 V
2022-01-06 08:003.303.303.303.303.303.303.303.30

On 2022-01-06, I disconnected the battery and started charging the individual cells. The BMS manufacturer i-tecc states that the BMS will balance the cells above 28.8 V, so each individual cell ought to be at 3.51 V.

date time UE AE US AS VI VB kWh ΔE ΔS C
2021-10-31 20:30 34.9 0.0 104 0.0 – 26.1 –
2021-11-02 20:30 35.0 0.0 105 0.0 – 26.3 –
2021-11-03 17:30 35.1 0.0 105 0.0 – 26.3 –
2021-11-04 19:50 35.1 0.0 105 0.0 26.1 25.5 136.7
2021-11-05 08:40 35.1 0.0 105 0.1 26.1 25.4 137.1
2021-11-05 12:00 35.1 3.0 105 4.9 26.5 25.7 137.2
2021-11-05 18:00 35.3 0.0 105 0.0 26.2 25.4 137.5
2021-11-12 17:50 37.3 0.0 110 0.0 26.4 25.7 141.9
2021-11-12 19:30 37.3 0.0 110 0.0 26.0 25.4 142.1
2021-11-18 08:40 37.4 0.1 110 0.1 26.3 142.1
2021-11-18 16:00 37.8 0.0 111 0.3 26.6 25.9 142.4
2021-11-18 18:40 37.8 0.0 111 0.0 26.4 25.7 142.5
2021-11-19 08:40 37.8 0.0 111 0.0 26.6 25.9 142.6
2021-11-19 10:40 37.8 2.3 111 0.3 26.7 25.8 142.7
2021-11-19 19:30 38.2 0.0 112 0.0 26.6 25.8 142.9
2021-11-20 10:40 38.2 0.3 112 0.6 26.7 25.9 143.0
2021-11-20 15:40 38.3 0.0 112 0.0 27.7 26.7 143.1
2021-11-20 18:40 38.3 0.0 112 0.6 26.5 25.8 143.3
2021-11-21 09:20 38.3 0.1 112 0.2 26.5 25.7 143.8
2021-11-21 17:40 38.3 0.0 112 0.2 26.2 25.5 144.4
2021-11-23 15:20 38.7 0.0 113 0.3 26.9 26.1 144.5
2021-11-23 21:40 38.7 0.0 113 0.0 26.5 25.7 144.9
2021-11-24 05:40 38.7 0.0 113 0.0 26.4 25.7 145.1
2021-11-24 11:00 38.7 0.1 113 0.4 26.4 25.7 145.3
2021-11-29 10:10 *25.9
2021-11-29 10:10 38.9 0.4 114 0.5 26.2 25.5 147.2
2021-11-29 11:10 38.9 0.6 114 0.7 25.8 25.0 147.3
2021-11-30 15:00 38.9 0.0 114 0.0 25.8 25.1 147.4
2021-12-01 17:00 25.8
2021-12-02 18:20 25.9
2021-12-03 10:40 39.0 0.8 114 0.7 26.3 25.6 147.4
2021-12-03 18:40 39.3 0.0 114 0.8 26.2 25.5 147.6
2021-12-07 10:50 26.3
2021-12-07 11:00 39.4 0.7 115 0.2 26.6 25.8 147.6
2021-12-07 20:00 39.7 0.0 115 0.0 26.1 25.5 148.3
2021-12-12 10:10 26.5
2021-12-12 10:20 39.8 1.7 116 2.2 26.1 26.0 148.3
2021-12-13 10:00 26.3
2021-12-13 10:10 39.9 1.1 116 0.9 26.6 25.8 148.7
2021-12-13 14:00 40.3 0.4 116 2.5 26.8 26.0 148.8
2021-12-13 18:10 40.3 0.0 117 0.0 26.5 25.8 149.1
2021-12-14 06:40 40.3 0.0 117 0.0 26.3 25.5 149.7
2021-12-14 22:20 40.6 0.0 117 0.0 26.3 25.6 150.4
2021-12-16 09:50 40.6 0.1 117 0.3 26.4 26.0 150.6
2021-12-16 17:10 40.6 0.0 118 0.0 26.1 25.7 150.8
2021-12-16 19:20 40.6 0.0 118 0.0 25.9 25.5 151.1
2021-12-16 20:50 40.6 0.0 118 0.0 26.0 25.5 151.3
2021-12-17 10:30 40.6 0.0 118 0.2 26.3 25.8 151.4
2021-12-17 20:20 40.7 0.0 118 0.0 25.7 25.2 151.9
2021-12-18 08:40 40.7 0.0 118 0.0 26.1 25.6 151.9
2021-12-18 12:50 40.9 4.4 118 9.8 27.0 26.4 152.1

2022-01-19: hooked up the new balancer. beforehand, battery cell voltages were 3.3, 3.3, 3.3, 3.3, 3.3, 3.34, 3.3, 3.3. total compumption so far 152.8 kWh.

2022-01-28: installed the new PUGU inverter and started using solar power again. before connecting the inverter, the battery cells seemed extremely badly balanced in spite of the active balancer connected, with #3 very high and #4 very low. total voltage started out at 28.2 V and rapidly dimished. after a couple of minutes of use they evened out somewhat: 3.32, 3.32, 3.44, 3.29, 3.29, 3.31, 3.31, total voltage 27.7 V, total kWh consumption at 152.8.

2022-01-29 20:10: 153.3 kWh, VI 27.1 V; inverter failed and switched off at 01:00 o’clock in the night.

2022-01-30 10:10: sunshine, 153.8 kWh, VI 27.9 V

2022-01-30 18:10: dark, 153.9 kWh, VI 27.3 V, VS 26.3 V, 120 kWh, VE 26.4 V, 41.9 kWh

2022-01-31 10:40: very cloudy, 154.0 kWh, VI 26.4 V, VS 26.6 V, 121 kWh, VE 26.7 V, 42.0 kWh, bms blocking intermittently, 3.31, 3.31, 3.30, 3.30, 3.49, 3.31, 3.31, 3.31 balancer is not working! five minutes later, things look ok, bms unblocked, inverter works again…

2022-02-03 13:20: new daly bms installed, balancer and i-tecc bms removed, up and running again. C 154.0 kWh, Vb 26.4, all cells at 3.3 V;
22:00 154.4 kWh 26.3 Vs

2022-02-04 08:40: hooked up east epever charger again; C 154.7 kWh, E 42.1 kWh 26.3 V, S 121 kWh 26.1 V

2022-02-05 14:30: rover charger installed, sunny: C 155.5 kWh, E 42.6 kWh 29.1 V, -0.1 A, S 122 kWh 29.0 V 0.7 A, V 28.7 V 40 V 7.5 A 30 Ah; 17:50 C 155.7 E 42.6 26.5 S 122 26.4 V 26.2V 33 Ah

2022-02-06 10:50: C 156.5 E 42.6 26.7 S 122 26.6 V 26.4V 5 Ah

2022-02-07 17:20: C 157.8 E 43.2 26.5 S 123 26.4 V 26.3V 45 Ah: kWh diff: C 1.3 E 0.4 S 1.0 V 1.0

2022-02-08 03:30: C 158.2 E 43.2 26.5 S 123 26.4 V 26.3V 45 Ah

2022-02-08 07:20: C 158.3 E 43.2 26.4 S 123 26.3 V 26.2V 45 Ah

2022-02-08 12:20: C 158.6 E 43.6 27.5V 7A S 124 28.8V 5.4A V 27.2V 11Ah

2022-02-08 20:00: C 159.1 E 43.6 26.5V 0A S 124 26.4V 0.0A V 26.2V 23Ah

2022-02-09 12:40: C 160.4 before running washing machine for the first time in full sunshine: it uses ca. 2100 W for some short periods of time; battery fully loaded with 29V before starting, suddenly sinking to 25.5V when fully loaded; charging during run: E 76V 1.3A 25.6V 3A S 44V 10A 25.3V V 63V 4.7A 26.7V 12A

2022-02-09 19:30: C 161.5 E 44.3 26.4V 0A S 125 26.3V 0.0A V 26.1V 47Ah; diff: C 2.4 E 0.7 S 1 V 1.2 sum 2.9

2022-02-10 midday: C 162.9 before running washing machine with a 60 degree load for the second time in full sunshine: battery not fully loaded before starting, but pretty full, suddenly sinking from ca. 27V to ca. 26V; charging during run: E 26.2V 6.8A S 27.1V 10.7A V 47V 13A C 164.1 after washing run.

2022-02-10 18:20: C 164.4 E 45.0 26.5V -0.1A S 126 26.4V 0.0A V 26.2V 49Ah; diff: C 2.9 E 0.7 S 1 V 1.2 sum 0.7 + 1 + 1.2 = 2.9

2022-02-11 08:40: C 164.4 E 45.0 26.5V -0.1A S 126 26.4V 0.0A V 26.2V 49Ah; diff: C 2.9 E 0.7 S 1 V 1.2 sum 0.7 + 1 + 1.2 = 2.9

2022-02-11 midday: C 165.7 before; power 1900 W; data from V: 13Ah before, battery voltage 27.1 reduced to 25.8, PV 46V 15A. C 16?.? after washing run.

2022-02-15 late evening: after two rainy cloudy days, the BMS blocked and switched off; i switcherd off the inverter; the battery pole voltage was 24.4V afterwards

2022-02-16 midmorning: still very dark, rainy and cloudy; after charging very slightly, i turned on the inverter again; that worked for a while, but switched on and off repeatedly when i turned on a bright light using 60W. battery cell voltages were 3.22, 3.22, 3.19, 2.95, 3.21, 3.22, 3.21. power so far: C = 174.2 kWh.

2022-02-17 12:50 inverter still switched off, gradually loading; cell voltages: 3.25, 3.25, 3.21, 3.16, 3.25, 3.26, 3.26, 3.26.

2022-02-18 08:20 inverter still switched off, loading and balancing; cell voltages: 3.27, 3.27, 3.24, 3.20, 3.27, 3.27, 3.27, 3.27; chargers report E 26.3V, S 26.2V, V 26.0V. voltmeter agrees with charger V on 26V. according to the voltage chart, this corresponds to ca. 50% SOC of the battery and most cells, and only 20% SOC for cell #4, after two days loading with overcast sky and no load.

2022-02-18 12:00 inverter still switched off, loading and balancing in a sunny moment, full sunshine producing ca. 900W; chargers: E 47.3 kWh, 70V, 3A, 27.3V, 7.8A, 210W; S 130 kWh, 73V, 4A, 28.5V, 10.3A, 290W; V 44V, 10A, 27.0V, 14Ah, 440W; cell voltages: 3.35, 3.33, 3.33, 3.32, 3.32, 3.34, 3.39, 3.50; all of them over 80% except the last at 99%; pretty weird, #4 jumping from 20% to 80% in just three hours; still waiting to see whether they will balance out more;

2022-02-18 14:00 inverter still switched off, loading and balancing, cloudy, producing ca. 460W: chargers: E 47.5 kWh, 70V, 0.8A, 27.0V, 2A, 54W; S 130 kWh, 75V, 1.6A, 28.4V, 4A, 110W; V 44V, 7A, 26.7V, 32Ah, 300W; cell voltages: 3.33, 3.31, 3.31, 3.30, 3.31, 3.33, 3.34, 3.38; all of them between 70-80% except the last at 99%;

2022-02-18 16:30 inverter still switched off, loading and balancing, sun setting, producing ca. 80W: chargers: E 47.5 kWh, 29V, 0.1A, 26.8V, -0A, 2W; S 130 kWh, 30V, 0.5A, 28.1V, 0.6A, 14W; V 41V, 1.8A, 26.5V, 40Ah, 70W; cell voltages: 3.32, 3.32, 3.29, 3.30, 3.29, 3.32, 3.33, 3.34; all of them between 65-90%;

2022-02-18 22:10 inverter still switched off, resting and settling at 26.35 V SOC ca. 45-50% with cell voltages: 3.30, 3.30, 3.28, 3.27, 3.30, 3.30, 3.30, 3.30; all around 70%, except #3 and #4 under 50%.

2022-02-19 12:50 inverter still switched off, sunny, producing ca. 0W, chargers refusing to charge: cell voltages: 3.38, 3.37, 3.33, 3.33, 3.63, 3.47, 3.42, 3.47; all of them over 96%;

2022-02-19 13:00 turned on inverter, sunny, producing ca. 70W, chargers: E 47.9 kWh, 87V, 0.0A, 29.1V, -0.1A, 0W; S 131 kWh, 89V, 0.0A, 29.0V, 0.0A, 0W; V 60V, 1.2A, 27.5V, 70W; cell voltages: 3.36, 3.36, 3.33, 3.31, 3.40, 3.39, 3.26, 3.15 = 26.2; this was measured while the discharge load was varying…

2022-02-19 19:20 inverter ran this sunny afternoon; chargers: E 26.4V, 47.9 kWh, S 26.3V, 131 kWh, V 26.1V, 37 Ah cell voltages: 3.28 + 3.28 + 3.28 + 3.28 + 3.28 + 3.28 + 3.27 + 3.25 = 26.2; battery overall and all cells at ca. 50% except #7 at 40% and #8 at 30%; C 174.7 kWh.

2022-02-19 22:20 C 174.9 E 26.5V, V 26.2V –> battery voltage 26.3V SOC ca. 55%.

2022-02-20 08:30 C 175.4 E 26.3V, V 26.0V –> battery voltage 26.1V SOC ca. 40%.

2022-02-20 20:30 C 176.3 E 48kWh 26.2V, S 131kWh V 12Ah

2022-02-20 22:30 C 176.6 E 26.1V, V 25.9V, SOC ca. 30%

2022-02-21 09:50 C 177.2, charging at 140W, E 48.0 kWh, 28V, 0.8A, 26.2V, 0.8A, 20W; S 131 kWh, 30V, 0.6A, 27.5V, 0.5A, 13W; V 44V, 2.5A, 25.9V, 2Ah, 110W; cell voltages: 3.25 + 3.25 + 3.23 + 3.20 + 3.24 + 3.25 + 3.25 + 3.26 = 25.93, ca 26% SOC.

2022-02-21 18:44 C 177.8, discharging, E 48.1 kWh, 0V, -0.0A, 26.0V, -0.0A, 0W; S 131 kWh, 0V, 0.0A, 25.9V, 0.0A, 0W; V 0V, 0.0A, 25.7V, 23Ah, 0W; cell voltages: 3.23 + 3.23 + 3.21 + 3.19 + 3.23 + 3.23 + 3.22 + 3.21 = 25.75, ca 20% SOC.

2022-02-21 switched off the inverter in the evening

2022-02-22 switched on the inverter in the morning; in the evening, at 19:30, he have C 178.5 kWh, E 48.5 kWh, 0V, -0.0A, 26.0V, -0.0A, 0W; S 132 kWh, 0V, 0.0A, 25.7V, 0.0A, 0W; V 0V, 0.0A, 25.8V, 43Ah, 0W; cell voltages: 3.24 + 3.24 + 3.24 + 3.24 + 3.24 + 3.24 + 3.23 + 3.21 = 25.88, ca 25% SOC.

2022-02-23 switched on the inverter in the morning; in the evening, at 19:30, he have C 179.7 kWh, E 48.7 kWh, 0V, -0.0A, 26.3V, -0.0A, 0W; S 132 kWh, 0V, 0.0A, 26.2V, 0.0A, 0W; V 0V, 0.0A, 26.0V, 34Ah, 0W; switched off again.

2022-02-24 switched on the inverter this morning; in the evening, at 21:40, C 180.3 kWh, E 49.1 kWh, 0V, -0.0A, 26.4V, -0.0A, 0W; S 133 kWh, 0V, 0.0A, 26.3V, 0.0A, 0W; V 0V, 0.0A, 26.1V, 41Ah, 0W; left it on for now…

2022-02-26 13:50 inverter still running non-stop, sunny, starting a 40 degree washing machine load; before C 182.7 kWh, E 50.1 kWh, 40V, 1.2A, 26.6V, 0.1A, 0W; S 133 kWh, 84V, 1.1A, 28.9V, 1.5A, 0W; V 53V, 0.0A, 26.9V, 42Ah, 0W; cell voltages: 3.35 + 3.35 + 3.35 + 3.35 + 3.65 + 3.50 + 3.42 + 3.36 = 27.33

2022-02-26 14:10 with the washing machine drawing over 2kW, and a total of 1270W coming in from PV, the battery voltage report drops to: E 50.1 kWh, 73V, 1.9A, 25.6V, 5.4A, 130W; S 133 kWh, 72V, 5.3A, 26.3V, 14.5A, 380W; V 45V, 17A, 25.4V, 45Ah, 760W; cell voltages: 3.16 + 3.22 + 3.23 + 3.25 + 3.23 + 3.21 + 3.10 + 2.96 = 25.35

2022-02-27 14:40 inverter still running non-stop, sunny, with another 40 degree washing machine run drawing 2kW and a total of 1kW coming in, the battery voltage report drops to: E 50.6 kWh, 72V, 1.1A, 25.1V, 3.0A, 75W; S 134 kWh, 73V, 4.9A, 26.3V, 13.5A, 355W; V 45V, 13A, 25.0V, 62Ah, 570W; cell voltages: 3.10 + 3.20 + 3.22 + 3.22 + 3.22 + 3.19 + 3.00 + 2.80 = 24.95

2022-02-28 09:30 inverter still running non-stop, sunny, just rising, 50W input, C 186.8 kWh, E 50.7 kWh, 28V, 0.2A, 26.2V, 0.2A, 5W; S 135 kWh, 28V, 0.2A, 26.3V, 0.2A, 5W; V 39V, 1A, 25.9V, 0Ah, 40W; cell voltages: 3.25 + 3.24 + 3.24 + 3.24 + 3.24 + 3.25 + 3.24 + 3.23 = 25.93

2022-02-28 18:30 inverter still running non-stop, sunny, C 188.4 kWh, E 51.5 kWh, 26V, 0.0A, 26.2V, 0.0A, 0W; S 135 kWh, 28V, 0.0A, 26.3V, 0.0A, 0W; V 18V, 0A, 26.1V, 66Ah, 0W; cell voltages: 3.27 + 3.28 + 3.28 + 3.28 + 3.28 + 3.27 + 3.25 + 3.24 = 26.15

2022-03-01 08:50 inverter still running non-stop, sunny, C 189.7 kWh, E 51.5 kWh, 28V, 0.0A, 26.1V, 0.0A, 0W; S 135 kWh, 28V, 0.1A, 26.1V, 0.1A, 2W; V 34V, 0.2A, 25.8V, 0Ah, 0W; in 4 days february 25-28 we produced and consumed 189.7 - 180.3 = 9.4 kWh

2022-03-03 08:30 inverter still running non-stop, sunny, C 193.6 kWh, E 52.7 kWh, 28V, 0.1A, 26.1V, 0.1A, 0W; S 136 kWh, 28V, 0.1A, 26.1V, 0.1A, 2W; V 30V, 0.3A, 25.8V, 1Ah, 0W; cell voltages: 3.24 + 3.24 + 3.24 + 3.24 + 3.24 + 3.24 + 3.24 + 3.23 = 25.91

2022-03-03 the south-facing epever tracer died; maybe due to too high current; its max rating is 10A, and the 4x100Wp panels may have provided up to 400W / 25V = 16A. i was still able to complete a 60 degree washing machine without it.

2022-03-04 inverter still running non-stop, sunny, ran another washing machine at 40 degrees; C 197.3 kWh in the evening with a voltage around 26.1V according to V.

2022-03-05 inverter still running smoothly non-stop, sunny; C 198 kWh in the morning with a voltage around 25.9V according to V. disconnected the broken S epever tracer charger

2022-03-10 18:40 inverter still running smoothly non-stop, sunny every day; cornelius washed three timnes in the oast few days, we washed once today; C 208.3 kWh with a voltage around 26.2V according to V. E 58.9 kWh; disconnected to hook up the new rnogy rover 20A charger for the S panels

2022-03-12 14:30 inverter still running smoothly; sunny; added the renogy rover 20a charge controller for the south-facing panels; C 209.9 kWh before starting washing machine; E 59.6 kWh, 85V, 0.1A, 25.5V, 2.0A, 50W; S 70V, 12A, 25.4V, 1Ah, 840W; V 54V, 8.5A, 28.7V, 4Ah, 450W;

2022-03-19 17:20 inverter still running smoothly; sunny; C 221.9 kWh; E 62.6 kWh, 83V, 0.0A, 29.0V, -0.1A, 0W; S 86V, 0A, 28.9V, 14Ah, 0W; V 53V, 1.4A, 28.7V, 30Ah, 0W; cell voltages: 3.41 + 3.31 + 3.31 + 3.31 + 3.62 + 3.65 + 3.32 + 3.32 = 27.25

2022-03-20 12:30 inverter still running smoothly, sunny, washing machine starting up; C 224 kWh, 1065W currently being generated; E 63.2 kWh, 79V, 2.0A, 25.8V, 7.2A, 185W; S 70V, 13A, 25.7V, 13Ah, 330W; V 42V, 20.6A, 26.9V, 36Ah, 550W before washing dust off the panels; V 43V, 21.7A, 27.3V, 40Ah, 590W after washing dust off the panels;

2022-04-01 20:00 inverter running smoothly but battery low after two dreary and very rainy days; C 250 kWh; E 70.2 kWh, 26V, 0.0A, 26.0V, -0.0A, 0W; S 26V, 0A, 25.9V, 12Ah, 0W; V 22V, 20.6A, 25.7V, 26Ah, 0W;

2022-04-06 12:30 inverter running smoothly, quite cloudy, trying to run the washing machine anyway: C 257.8 kWh before; E 72.2 kWh, 76V, 1.4A, 27.5V, 3.6A, 0W; S 74V, 6A, 27.4V, 11Ah, 0W; V 42V, 11.0A, 27.3V, 23Ah, 0W; during washing with 2kW load, battery voltage drops to 24.5V;

2022-04-11 11:00 inverter running smoothly, sunny, before running the washing machine: C 266 kWh before; E 74.1 kWh, 68V, 3.2A, 27.4V, 8.9A, 0W; S 83V, 2A, 27.2V, 2Ah, 0W; V 44V, 4.0A, 27.1V, 6Ah, 0W; during washing with 2kW load, battery voltage drops to 24.6V;

2022-04-13 yesterday, i installed the hot water boiler. today was sunny and the battery pretty full, so i turned on one 650 W heating element, and for a while even two. after one day, the boiler consumed 4.7 kWh, and our total PV consumption jumped to 275 kWh. the boiler is now over 25 degrees. according to the calculator, it will require ca. 10.5 kWh more to reach 55 degrees, which will take 17 more sunny hours at 650W. that may be achievable in two or three days. at their maximum, the chargers were producing ca. E 6, S 13, V 22 = 40 A E 76.5 kWh, 29V, 0.2A, 26.9V, 0.2A, 0W; S 72V, 1.3A, 26.7V, 68Ah, 0W; V 42V, 2.3A, 26.6V, 114Ah, 0W; so, the S+V chargers report 182Ah * 24V = 4368 Wh produced today.

2022-04-14 sunny day and charging the boiler. C = 277.4 kWh at 12:40. amperes coming on from the chargers E/S/V/total: 12:40 8.5 + 12 + 15 = 35.5 = 852W 13:30 7.7 + 13.2 + 21.4 = 42.3 = 1015W 16:00 a = 2.2 + 12.2 + 16 = 30.4 = 730W 16:20 a = 0.7 + 11.7 + 15.5 = 27.9 = 669W 17:20 a = 0.3 + 3.2 + 7.5 = 11.0 = 264W 17:20 consumption so far: total C 280.8, boiler B 9.0 kWh, temperature ca. 34 degrees. E 77.8 kWh, 29V, 0.2A, 26.9V, 0.3A, 0W; S 49V, 1.8A, 26.7V, 67Ah, 0W; V 42V, 6.7A, 26.6V, 107Ah, 0W; so, the S+V chargers report 174Ah * 24V = 4176 Wh produced today, E = 77.8-76.5 = 1.3kWh, total 5.4 kWh. C increased by 280.8-275 = 5.8 kWh. weird, where is the loss?

2022-04-17 18:30 after two previous days feeding the boiler and today one sunny day with one washing machine load and no boiler, sun gone from the panels, battry fully charged: C = 294.3 kWh, E 81.3 kWh 29.1V, S 73 Ah = 1.75 kWh 28.9V, V 110 Ah = 2.64 kWh 28.8V; cell voltages: 3.35 + 3.31 + 3.31 + 3.31 + 3.58 + 3.48 + 3.31 + 3.31 = 26.96

2022-04-18 08:50 after one night’s gentle discharging: C = 295.2 kWh, E 81.3 kWh 26.3V, S 1 Ah 26.1V, V 0 Ah 26.0V; cell voltages: 3.27 + 3.27 + 3.26 + 3.24 + 3.27 + 3.26 + 3.25 + 3.27 = 26.09

2022-04-27 14:10 sunny and cloudy alternating, charged the boiler with 600W for two hours, now switched to 1200W. B = 34.9 kWh C = 327.6 kWh, E 90.1 kWh 26.7V 8A, S 25 Ah 25.1V 5A, V 44 Ah 25.0V 11A;

2022-04-28 12:10 sunny. voltages before and after switching on 600W boiler: B = 36.6 kWh C = 330.6 kWh, E 91.0 kWh 28.1/27.1V 8A, S 6 Ah 27.9/27.0V 11A, V 11 Ah 27.7/26.8V 8A;

s2022-04-28 14:10 very sunny. voltages before and after switching boiler from 600W to 1.2kW: B = 37.8 kWh C = 331.9 kWh, E 91.4 kWh 29.0V 6A / 26.8V 6A, S 25 Ah 29.0V 0A / 26.6V 14A, V 43 Ah 29.0V 20A / 26.5V 25A;

2022-04-28 16:30 very sunny. voltages before and after switching boiler from 1260W to 600W: B = 38.8 kWh C = 335.1 kWh, E 91.7 kWh 25.6V 0.3A / 26.5V 0.3A, S 60 Ah 25.5V 13A / 26.5V 12A, V 95 Ah 25.3V 16A / 26.3V 16A;

2022-04-28 17:20 sun going behind roof ridge. voltages before and after switching off boiler from 632W: B = 41.4 kWh C = 335.7 kWh, E 91.7 kWh 26.0V 0.1A / 26.8V 0.0A, S 60 Ah 26.0V 7A / 26.6V 2A, V 95 Ah 25.8V 7A / 26.5V 7A;

2022-05-18 12:10: the walnut tree has developed its leaves and shadows the S and V panels totally until noon. B = 77.4 kWh C = 398.1 kWh, E 110 kWh 65.0V 3.8A / 27.8V 8.6A, S 4 Ah 49V / 27.7V 8A, V 95 Ah 41V / 27.5V 2A;

2022-06-04 14:20 back from a week-long break, sunny day, second washing machine load for today: B 92.1 C 431.7 E 122 kWh 28.0V 2.9A / 25.2V 4.2A, S 23 Ah 64V / 24.9V 14A, V 25 Ah 34V / 24.8V 23A;

2022-06-04 14:50 run in boiler 600W B 92.1 C 431.7 E 122 kWh 81.0V 0.0A / 27.1V -0.1A, S 26 Ah 65V / 27.1V 12A, V 30 Ah 31V / 27.1V 20A;

2022-06-21 ca. 17:00 my entire PV installation shelf fell off the wall, ripping out the plugs from the brickwork; everything fell down 3 metres onto the wooden stairs: battery cells, bms, inverter, three chargers.

2022-06-23 18:00 all systems go again, with only the V panels and charger running so far; B 116.3 C 480.4 E 139 kWh 0.0V 0.0A / 26.4V -0.1A, S 0Ah 0V / 26.3V 0A, V 0Ah 34V / 26.1V 1A;

2022-07-22 17:20 after a month full of sun and the boiler running most days, it never quite reached 50 degrees, and the gas consumption did not niticeable decrease in spite of that; 111 kWh generated in 35 days, 40 used by boiler, 70 kWh by moniwonig; B 166.8 C 571.7 E 169 kWh 29.0V 0.3A / 27.0V 0.2A, S 48Ah 35V / 26.9V 4.6A, V 91Ah 35V / 26.7V 8.6A;

2022-08-09 11:40 moni and i were away for two weeks, so nobody touched the PV system and the boiler was turned off all the time except yesterday. yesterday, 2022-08-08, we ran two washing machines full and also ran the boiler at 1200 W for ca. two hours and 600 W for ca. 3 more. voltages before turning on the boiler: B 173.9 C 579.9 moni grid usage G 0.3 kWh E 181 kWh 67.0V 3.6A / 27.2V 9.1A, S 3Ah 60V / 27.1V 8.3A, V 3Ah 40V / 26.9V 1.4A; with 600 W bolier load: E 181 kWh 67.0V 3.6A / 26.8V 9.0A, S 3Ah 60V / 26.6V 10.0A, V 3Ah 40V / 26.4V 1.5A;

2022-08-23 15:10 i was away since 2022-08-15, so no boiler usage for nine days; turned on the boiler today at 12:00, so ca. 2 kWh already used just today; B 196.8 C 636.2 H 644.3 moni grid usage G 0.3 kWh; with 600 W bolier load: E 192 kWh 67.0V 1.7A / 26.7V 4.2A, S 29Ah 34V / 26.6V 7.8A, V 48Ah 35V / 26.5V 18A;

2022-08-25 08:30 forgot and left the boiler running at 600 W all night, so the battery was emptied and the BMS blocked because one cell went way down: cell voltages: 3.19 + 3.17 + 3.17 + 2.59 + 3.19 + 3.20 + 3.18 + 3.18 = 24.87

2022-08-25 11:10 all system go again; had to disconnect and reconnect the S chanrger; it complained that the battery was over-charged and did not notice that it was back to OK again. cell voltages: 3.27 + 3.24 + 3.22 + 3.20 + 3.26 + 3.27 + 3.25 + 3.26 = 25.97 B 208.5 C 643.9 H 644.7 moni grid usage G 0.3 kWh; with 600 W bolier load: E 193 kWh 66.0V 3.8A / 26.3V 9.4A, S 0Ah 77V / 26.2V 1.0A, V 1Ah 35V / 26.0V 1A;

2022-08-31 cell voltages: cell #5 reaches 3.65 and triggers the BMS to turn off, preventing the other cells from charging further: 17:50 small load: 3.31 + 3.32 + 3.31 + 3.31 + 3.62 + 3.48 + 3.32 + 3.32 = 26.99 17:55 600 W load: 3.20 + 3.27 + 3.27 + 3.26 + 3.28 + 3.27 + 3.27 + 3.19 = 26.01 18:00 small load: 3.31 + 3.30 + 3.30 + 3.31 + 3.31 + 3.31 + 3.30 + 3.32 = 26.46

2022-09-30 07:40 after two very dreary and rainy days, E reports 25.4 V battery voltage; an hour ago, it was still at 25.6 V;

2022-10-10 12:30 sunny day; all systems still going strong, boiler charging at 600 W: B 252.6 C 742.0 H 655.31 moni grid usage G 12.0 kWh; with 600 W bolier load: E 217 kWh 75.0V 2.6A / 26.9V 7.1A, S 6Ah 77V / 26.8V 11.0A, V 8Ah 35V / 26.6V 10 A;

Meter Readings Winter 2022-2023

2022-11-30 13:40 raised 5 of the V panels to an angle of ca. 70 degrees, facing 57 degrees south and 33 degrees west. last week, we had pone sunny day and were able to run a washing machine from solar power. all other days were rainy and cloudy, and we often had to turn off the solar power and switch to grid in the evenings or through the night. B 259.8 C 799.7 H 667.16 moni grid usage G 35.4 kWh; E 230 kWh 28.0V 0.8A / 26.5V 0.8A load 27.0 kWh; S 13Ah 72V / 26.4V 2.3A, V 13Ah 40V / 26.3V 3.3A

2022-12-18 12:20 i was away for two weeks, the solar system was mostly switched off, some snow covering the V panels, sunny day; 25.6 at night with inverter switched off, went up to 26.1 the sun at 12:00 and with some snow cover, went up to 26.4 after sweeping off some snow, went down to 26.1 after switching on the inverter, up to 26.4 again after raising the last row vertically and sweeping off more snow, even with less sun, at 13:10.

2022-12-19 09:50 battery hasd 25.9 when i went to bed after 11 o’clock at night, and was down to 25.3 in the early morning, so i switched the inverter off again; 25.7 at nine o’clock in the morning; 09:50 no load, some light: 3.24 + 3.21 + 3.21 + 3.19 + 3.24 + 3.23 + 3.21 + 3.23 = 26.99 C 802.7 moni grid usage G 35.4 kWh; E 231 kWh 28.0V 0.2A / 26.0V -0.1A load 27.8 kWh; S 1Ah 52V / 25.8V 0.8A, V 1Ah 40V / 25.7V 1.3A

2022-12-30 09:50 the battery cells are deteriorating, it seems; several times in december, they did not loast overnight and i had to switch off in the middle. the voltage loss overnight with only 20 W load plus the fridge running occasionally with 60 W can be: 26.3 –> 26.2; 26.2 –> 26.0; 25.9 –> 25.8; 25.8 –> 25.3; E 232 kWh 28.0V 0.1A / 26.1V -0.2A load 28.3 kWh; S 1Ah 53V / 26.0V 1.2A, V 1Ah 31V / 25.9V 0.7A B 259.8 C 806.2 H 674.15 moni grid usage G 67.9 kWh;

2023-01-01 17:10 after three days and two nights away with the last two days nice an sunny: E 233 kWh 22.0V 0.0A / 26.3V -0.3A load 28.4 kWh; S 40Ah 22V / 26.2V 0.0A; V 36Ah 39V / 26.1V 0.0A; B 259.8 C 808.0 H 674.15 G 67.9 in these three days, we gained 1 kWh from E; today alone, S gave 1 kWh and V 900 Wh; however, C only gained 1.8 kWh, and E load 0.1; so, the chargers report a lot more power going in than we are taking out of the inverter;

2023-01-02 12:50 in full sunshine E 233 kWh 73.0V 1.8A / 27.2V 4.6A load 28.5 kWh 115W; S 15Ah 72V / 27.1V 10.6A 265W; V 16Ah 43V / 26.9V 13.4A 335W; B 259.8 C 808.5 H 674.15 G 68.2

2023-01-03 11:30 moderately cloudy E 233 kWh 28.0V 0.2A / 26.4V -0.1A load 0.3 A 28.5 kWh W; S 4Ah 73V / 26.3V 1.7A W; V 4Ah 41V / 26.1V 1.7A W; B 259.8 C 809.4 H 674.15 G 68.5

2023-01-12 09:40 after several cloudy and rainy days, mostly stayed on grid power. at 23:00 yesterday, the battery indicator said 26.0 V. turned on the inverter; it sank to 25.9. at 05:00 this morning, it was down to 25.6 and i switched back to grid. now with some light but quite cloudy, the battery indicator said 26.0 V again. turned on the inverter; it sank to 25.9. maybe better to keep it on during the day and use the power immediately instead of trying to store anything in the decrepit battery.

2023-01-12 12:00 still cloudy, battery indicator down to 25.7 V, switching to grid mains to plug in PC.

2023-01-17 /Users/jta/j/doc/fin/tax/fr/2022/mksteuer/2023_01_Monatsinformation.pdf Photovoltaikanlagen steuerfrei Einnahmen aus kleinen Solarstromanlagen sind rück- wirkend ab Jahresanfang 2022 steuerfrei. Ab 2023 entfällt für Kauf und Installation von Photovoltaikanagen bis zu einer Leistung von 30 Kilowatt und Stromspeichern die Umsatzsteuer von 19 %.

2023-01-21 13:10 sunny, lots of energy coming in, E charger switched off due to high voltage, the other two are charging, turned on the boiler, load 700 W: cells: 3.20 + 3.20 + 3.20 + 3.23 + 3.18 + 3.17 + 3.17 + 3.20 = 25.55

2023-01-21 13:40 sunny, lots of energy coming in, turned off the boiler, load 270 W: cells: 3.11 + 3.11 + 3.11 + 3.11 + 3.11 + 3.11 + 3.11 + 3.11 = 24.88 yet the battery indicator voltage is much higher, and the chargers too: E 235 kWh 29.0V 0.3A / 26.5V 0.3A load 0.1 A 29.5 kWh W; S 22Ah 78V / 26.4V 3.0A W; V 26Ah 31V / 26.3V 4.0A W; B 260.0 C 817.9 G 89.7 H 679.38

2023-02-08 12:20 in full sunshine: 7 + 11 + 17 = 35 A –> 875 W with 750 W load

2023-02-08 15:50 in full sunshine: 4 + 12 + 19 = 35 A –> 875 W with 1280 W load, but only briefly

2023-02-08 14:00 in full sunshine: 4 + 12 + 19 = 35 A –> 875 W with 650 W load E 237 kWh 81.0V 1.4A / 26.8V 4.9A load 0.2 A 30.2 kWh W; S 32Ah 73V / 26.8V 12.0A W; V 44Ah 44V / 26.6V 18.0A W; B 262.0 C 827.0 G 108.0 H 684.03

2023-02-08 22:20 after a day of full sunshine: E 237 kWh, S 53 Ah, V 72 Ah, so at least 3125 Wh input just from the S and V chargers

2023-02-09 09:40 clear sky but no direct sun yet: E 237 kWh 29.0V 0.4A / 26.5V 0.1A load 0.1 A 30.2 kWh W; S 1Ah 60V / 26.4V 0.7A W; V 0Ah 41V / 26.2V 0.7A W; B 262.4 C 828.7 G 108.5 H 684.26

2023-02-08 12:10 in full sunshine: 7 + 10 + 13 = 29 A –> 725 W with 650 W load

2023-02-08 13:40 in full sunshine: 4 + 12 + 19 = 35 A –> 875 W with 1330 W load, for a little while

2023-02-08 14:30 in full sunshine: 2 + 11 + 16 = 29 A –> 725 W with 650 W load

2023-02-09 13:00 in full sunshine: 5 + 11 + 18 = 34 A –> 850 W with 650 W load

2023-02-09 14:30 in full sunshine: 2 + 11 + 16 = 29 A –> 725 W with 650 W load

2023-02-09 23:00 E 238 kWh, S 51 Ah, V 71 Ah –> 3 kWh from S+V alone

2023-02-10 09:40 clear sky, sun coming: E 238 kWh 41.0V 0.5A / 26.6V 0.6A load 0.1 A 30.2 kWh W; S 1Ah 80V / 26.5V 1.8A W; V 1Ah 42V / 26.3V 1.1A W; B 264.9 C 832.1 G 109.0 H 684.53

2023-02-10 12:30 sunny: 5 + 11 + 18 = 34A = ca. 825W PV input, boiler turned on, 650 W load

2023-02-12 sunny day with careful protocol of voltages with and without load: 08:00 26.3 after the night; 11:20 27.4 without boiler 11:30 26.1 with boiler load 650W 11:40 26.3 with boiler 11:50 26.4 with boiler 14:00 27.0 with boiler 14:10 28.8 with boiler 650W, 4 + 13 + 19 = 36A = ca. 900W input from PV chargers 14:20 25.3 with additional boiler total load 1260W, turned off additional load again soon 15:10 26.3 with load 650W, 1 + 11 + 11 = 23A = ca. 625W input from PV chargers

2023-02-13 08:20 C 842.2 G 109.0 H 685.34 B 271.9

2023-02-13 11:00 7 + 5 + 4 A –> 400 W

2023-02-13 18:30 after a sunny day C 845.2 E 248 kWh S 63 Ah V 81 Ah –> 3.6 kWh today from S+V

2023-02-14 07:30 26.2V after the night 2023-02-14 08:10 26.1V C 845.8 G 111.2 H 685.61 B 274.4 (G consumption due to baking a loaf of bread in the electric oven)

2023-02-16 12:50 sunny day 6 + 12 + 20 2023-02-16 18:00 26.2V C 855.4 G 111.2 E 242 kWh S 39 Ah V 60 Ah 2023-02-17 09:30 26.1V C 856.2 –> 0.6 kWh used overnight for lighting and fridge

2023-02-19: components that i have for the new system: ich habe schon etliche komponenten vorraetig:

2023-02-20: lay down the back row of the V panels flatter again before the storm

2023-04-09: after a full day of sunshine and the boiler consuming 600W from 11:10 until 17:00, almost 6 hours, ca. 3.5 kWh, water temperature over 25 degrees in just one day; E 257 kWh 29.0V 0.1A / 26.7V 0.1A load 0.1 A 33.1 kWh W; S 61Ah V / 28.8V 0.0A W; V 104Ah V / 28.8V 0.0A W; B 307.4 C 932.5 G 128.4 H 696.23, S+V alone produced 165 Ah at ca. 25V today, over 4 kWh

2023-04-10 8:00: C 933.0 G 128.4 E 257 kWh 28.0V 0.0A / . V 0. A load 0. A 33.1 kWh W; S 0Ah V / 26.3V 0.3A W; V 0Ah V / 26.1V 0.4A W;

2023-04-10 10:20: 26.8V before turning on boiler, 26.3V afterwards, with 600W extra load

2023-04-10 22:20: 26.8V before turning on boiler, 26.3V afterwards, with 600W extra load C 937.7 G 129.3 E 257 kWh 28.0V 0.0A / . V 0. A load 0. A 33.1 kWh W; S 52Ah V 88Ah S+V alone produced 140 Ah at ca. 25V today, 3.5 kWh

2024-12-04 15:40 cloudy, about to install new batteryand jk bms; cell 4 is way off: cells: 3.29 + 3.31 + 3.31 + 2.77 + 3.11 + 3.31 + 3.31 + 3.28 = 25.69

Meter Readings Summer 2023

north electricity meters after installation of pvn: date time grid pvn pv moni wwwp deltas 2023-10-08 11:10 46077.1 0.3 272.3 264.5 251.5 2023-10-08 16:10 46077.4 2.0 274.0 264.5 252.9 2023-10-09 07:30 46079.9 2.2 274.8 264.5 253.2 2.5 0.2 0.8 0.3 night 2023-10-09 19:40 46081.6 3.6 276.4 264.6 254.4 1.7 1.2 1.6 1.2 day 2023-10-19 12:40 46143.2 15.0 294.9 270.8 271.6 cloudy and rainy day with wwwp on grid mains and no pv gain 2023-10-19 14:10 46144.2 15.0 294.9 271.6 272.3 1.0 0.0 0.0 0.8 0.7 2023-10-19 14:30 46144.4 15.0 294.9 271.7 272.4 1.2 0.0 0.0 0.9 0.8

PVM Readings Winter 2024