The pack is 10.5kWh, which is capacity and has little to do with performance.
They are limited to 37A per battery, that is the DCL that is set, so 111A. That is the normal continuous operation range.
So at 52V = 5772VA.
Relying on “peak” performance for that system is not a great idea. Low frequency inverters need to “lean” on the battery for transients, which you can often get away with when everything works fine, but when grid has an issue, the pack takes a beating.
The minimum numbers of batteries required is reasonably well documented on the victron site, though uses the lesser powered US2000’s, but you can do the maths from there.
Oh, thank you for the explaination. That is very helpfull.
The system was never at this limit. The last 30 days the maximum load was 1500W. In last summer there was a maximum of 5000 W for e few times, when a waterpump run. At that time the error appeared for the first time and then again only in December. Now the system is running fine for two weeks.
That makes it so difficult to find the reason. The best reason for me at the moment is a weak grid. We are in the country side and this system is at a farmer who is at the edge of the village.
I think that this coupled with the banks inability to deal with inrush because of its DCL ability may have something to do with it.
(You can see it in the voltage dive when current is drawn.) Though i don’t think its the whole picture because log distance is 60seconds and alot can happen in that time.
The system seems to self recover so to me this seems the most logical reason.
Maybe LOM detection and weak ac enabled will help and closing up grid voltage tolerance wil help so it rejects earlier.
Ultimately though I think you need a more robust DC bank. The batteries will have started to age now and the issue will only get worse.