Battery stops exporting around 15-25%

Hi,
I've recently noticed an odd behaviour on my battery when exporting (Gen3 hybrid inverter + 9.5kWh battery) - it gets to 15-25% of charge and stops exporting. Few screenshots to demonstrate:

Should have stopped exporting at 4am here:

Should have stopped exporting at midnight here:

I've tried running a battery calibration but it didnt help. I'm on 3019 firmware. GivEnergy support just emailed me back and said I should phone them to run through some troubleshooting steps (but I wont be able to call them until Thursday). Has anyone seen anything like it?

arczi19 the obvious thing is to check your battery reserve hasn’t been set wrongly

even if it shows as 4% in the app/portal, change it to a different value and change it back again to force it to 4%

arczi19 You're way below 25% SoC with that battery voltage - looks completely flat to me. Nothing anyone here can do, sounds like support are going to check to see whether its faulty or not.

Vestas Hmm that’s my worry too, but surely email support should have been able to see it from their side and not direct me to their phone support?

geoffreycoan It’s set at 4%, but good idea, I will set it again and see what happens tonight.

arczi19 It’s set at 4%, but good idea, I will set it again and see what happens tonight.

Can I just check - you've said in the topic the battery stops exporting... do you mean that as in forced-export-to-the-grid (usual usage here), or simply discharging to cover consumption ?

If the latter, there is another oddity related to reserve that my gen-3-hybrid system exhibits... if I have a discharge slot configured with a minimum SoC, then even if export is not enabled, the minimum charge level is honoured.

DD I meant forced export to the grid in both cases 🙂

arczi19

I see from another thread that you use home assistant - have you checked the individual cell voltages that it makes available ?

DD This is from last night where the problem occurred just before 4am:

arczi19 I think I read on here that a 200mV spread is a bit of a danger sign for weak cells. And it looks like that cell that had the lowest voltage at the bottom also has the highest voltage when charging ?

And from the chart linked from https://community.givenergy.cloud/d/1931-sudden-battery-discharge/13 2.8V is very low.

I have no idea if this is something that rebalancing can address - I've read that allowing the battery to idle for several hours at a lowish state of charge allows rebalancing.

Have you considered exporting at a lower power for longer? Higher power tends to exercarbate cell weaknesses. (Not that you should have to, in terms of warranty, etc, but keeping the power down may be kinder, and help with longevity.)

(My battery typically runs out by the end of the day, and often the SoC creeps up from 4% to 8% while it's idle, and then it's able to discharge a little more.)

arczi19 Mine's exactly the same, I believe it is a known bug with certain battery bms 3019 systems.

[unknown] Interesting. I've reached out to support and they've now updated my inverter to a beta firmware, with the hope that it will fix these problems.

Inverter beta firmware update did not help it seems. I have then asked to for my battery to be reverted to 3017 and it looks like the problem went away. Hopefully this bug gets fixed before they release it to the public.