Hi All i have a Victron Quatro multiplus 2 48/10000 with 920Ah Flooded Lead acid batteries with 8kw solar and 3MPPTs connected by CANbus a 712BMS on the battery but the battery only ever uses 400Ah before going into sustain i have set the ESS to charge off peak through the night for 4 hrs and the 712 says 95% on most nights. i have played with the charging profile to try and get the most out of the battery but can get any joy, any ideas?
Kind Regards
Simon
Sustain is triggered by the battery setting in ESS. Since you don't have a VE bus bms, I suggest lowering the dynamic cut off voltages in the ESS assistant.
See sustain in the ESS manual.
How long is your system supposed to stay in absorption? the duration on the one picture seems a bit short for flooded lead acid.
Pb batteries can show some serious V-sag under load when they get down a bit. I don't like what mine do at 70% SOC, and below that I've never seen, but I wouldn't expect much. And if they're cold it gets much worse.
Bear in mind that the BMV's Ah is measured from the last sync, and if that's premature then that's a bad start. But I think what you're seeing there is typical, well at least not unusual.
Your BMV could probably use some attention to it's settings. The 70% it's drawn down to seems optimistic to me, and the apparent sync that's showing there has adjusted like 10%. That may be over a few days, but that's a lot.
Seems your 8kW of solar is suffering, and if your 4hrs of grid is max, you could try pushing more Amps. You've maybe set for 10% A/Ah and that's fine, but they could handle more.
Cold weather could explain a lot of this. And if it's not cold now then it'll get worse when it does.
