I have a Gen-1 Giv-AC3.0 inverter coupled to single 8.2 battery. Operating since 2021. It now reduces charging rate to 400w at anything over 65% charged. Similarly reduces discharge rate below 25%. I've done the usual, reset to defaults, Re-start inverter and now full calibration, all to no effect. Inverter Monitor shows cell 14 with a higher voltage by up to 189mV (at 64% charged) above the other cells. I'm thinking the odd cell is the cause of the reduced charge rate; do you agree? Is the consensus that the battery is finished? Or is there anything else I should try?
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#2Rubikcube
What firmware is the battery running?
Does it get charged to 100% most days?
When it reaches 100% is a BMS overvoltage error or battery overvoltage error logged?
What is the terminal voltage in the error message (if there is a message)?
When at 100% what is the voltage of the highest cell?
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#3DavidHitchcock
Battery is on 3022 Inverter DO.212-AO.212
100% every day in the summer due to surplus pv.
No error logs on your app since calibration (BMS high voltage 57.38 & BMS low voltage 45.1; presumably as expected)
No errors on Givenergy portal.
Sorry didn't note high cell voltage, but can do so later tomorrow when it (eventually) reaches 100%
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#4DavidHitchcock
A few cycles since previous email with time spent at 100%, but no improvement.
It still only charges around 400w above 65% - 70%
Maximum cell-14 voltage was 3.498V 140mV above lowest at the time.
Do you think the battery is finished?
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#5Vestas
DavidHitchcock Run it through three or four charge/discharge cycles with the charge/discharge power set to 900W & see if it'll pull the cell a bit more in line with the others. Leave it set to discharge for at least two hours after it cuts out as the battery will rebalance at the low end & may recover some charge in the process. That will ensure the SoC is more or less correct.
Disable PV power while doing this - you want a nice steady charge/discharge current and PV will screw that up.
The process will take at least three or four days.
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#6DavidHitchcock
Vestas Thanks, I'll give it a try and let you know...
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#7Vestas
DavidHitchcock It may or may not work in terms of your charging problem, but it should pull that cell closer to the others - assuming damage/wear hasn't made that impossible.
Edit - one cycle at 900W is roughly equivalent to what GE would do for a "slow calibration" when you have an outlier cell.
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#8Rubikcube
Nobody knows how long GivEnergy Batteries will last. It would be disappointing if it has failed after 5 years. Even mobile phone and laptop batteries tend to last longer than 5 years.
Sounds like you are doing everything right. Do what you can to try and fix it and if anything works, do let us know. We are all in the same boat wondering how long our systems will last.
Would you be capable of loading 3017 firmware onto the battery? No idea if it would make any difference.
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#9DavidHitchcock
The battery was trouble from day-1 really, and I've often thought I should have chosen a different option.
Initially, a poor connection between battery and inverter (installer error) caused lots of issues, and after a few months the inverter failed completely; this was eventually replaced in June 22
SOC errors persisted right through until the 3020 update in (about) April-25, which more or less sorted it.
It was then well behaved until the current issue.
The current issue started more or less overnight (during the very hot weather here in Cambridgeshire)
I'll come back and update you by the end of the week...
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#10Vestas
DavidHitchcock NB - you'll have to set the battery to export at 900W.
Given the size of the battery I'd set it to discharge for 11.5 hours at 900W, 30 minutes "idle", then charge for 11.5 hours at 900W, 30 minutes "idle" and rinse/repeat a couple of times.
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#11DavidHitchcock
Currently under way with second cycle; will update once 3 or 4 cycles are complete.
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#12DavidHitchcock
I've now completed 3 full charge / discharge cycles at 900w leaving around 3-hours (at full or empty) between cycles.
It has performed identically on each cycle.
Discharge continued at 900w until it reached 4%
Charge continued at 900w until it reached 79% (Cell-14 highest voltage 3.49v)
It then reduced the charge to 400w until full.
As the 3 cycles were identical I assume there is no benefit in continuing with this, so will start to use it normally now and see how it goes.
If anyone can add any further help / advice I'd be interested.
Otherwise, I think it likely I'll be looking at replacement soon.
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#13Rubikcube
Would be interesting to know what happens if you load 3017 onto it. 3020 and 3022 are essentially the same but 3017 works quite differently.
Doing it via the dongle is safer than opening the battery, but you need to rename the file:
Remove the Dongle from inverter
Unzip the required file and inside will be BMS_ARM.bin
Rename this as ARMStore.bin
Place the Dongle in a laptop and a USB drive will appear
There should only be MSN.txt files on here. If anything else eg ARMStoreT.bin - Get rid if it
Copy the battery file now named ARMStore.bin onto the Dongle.
Eject and remove from laptop
Place it back in the inverter
Inverter will see the update file and process it to itself initially, then onto the battery
Battery will show red/green LED flashing and then reboot with a beep
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#14DavidHitchcock
Thank you for the clear instructions, but I do have reservations about 3017: -
3017 was the worst for SOC issues when installed previously (Nov-24 - April-25).
Frequently it would plummet from 45% - 4% or increase from 70% - full in minutes.
Then a full charge would only be 5 - 6 kw instead of 8-ish,
I also had several occasions when the battery cut out completely when it was charging and I had to re-start it (with the button on the side).
I was glad to see the back of 3017 when 3020 solved all of the above.
I do wonder if 3020 has just been very good at hiding a long-standing issue?
