I’m currently monitoring a newly installed Victron ESS.
There’s 15 kWp of solar on the roof connected to an SMA Tripower X. In the utility room, there are three MultiPlus 48/5000 units connected to six Pylontech US 3000 C batteries.
Yesterday evening, it charged his BEV. The wallbox (EVCS) charged at 11.5 kW. During this, around 1.7 kW was drawn from the grid.
The batteries’ SoC dropped from 78% to 60% during that time. (It was only plugged in for half an hour.)
Why didn’t the entire load come from the batteries? The utility room is around 25–28°C.
Are the MultiPlus units at their power limit, or is the batteries’ maximum permissible discharge current the limiting factor? More batteries could still be added in that case, couldn’t they?
It’s just out of interest for now; he could also limit the wallbox’s charging current to 14 A if necessary, in which case everything would probably come from the battery anyway.
There were presumably other loads running in the house besides the car as well.
At an ambient temperature of 28°C, it is quite possible that the MultiPlus units had already started reducing their output.
Six US3000s can deliver a combined 222 A; at 50 V, that amounts to 11.1 kW, so the batteries are already operating at their limit too.
Under heavy load, the voltage is probably somewhere around 48 V, so at 222 A that works out at about 10.6 kW — and that translates to roughly 9.5 kW on the AC side.
I have three MP 5000s myself, but with 16 Pylontech modules. The MultiPlus units can manage around 13 kW of output when they’re running hot (roughly speaking).
The other loads in the house are negligible; normally, they only amount to around 80–120 W, including the TV. I can’t get it that low.
Okay, then it really does seem that the Pylontechs will be the bottleneck. I suppose we won’t decide whether to expand the battery until after the winter.
As an immediate measure, I’ll probably recommend that he limit the charging current to 13 A or 14 A.