We have installation with 3-phase setup with multiplus-II and RS 450/200 with three solar arrays connected with total Wp over 10kW. There is 280Ah battery with JK-BMS connected which the inverters are able to use just fine and it is visible on Venus OS. It is sunny outside and the system provides 31W of solar power. How can this be and what could be the possible reasons MPPT chargers do not charge batteries or provide energy to inverters? There is plenty of load as well to dump the energy to, but no…
Pls check your BMS settings. Pack full or absorbtion voltage is quite high. I recommedn 55.2V (3,45V/cell), not 56.8V.
Float voltage can be increased to 54,4V (3,4V/cell).
Andi Offgrid Garage on YT provide many information about BMS settings.
Pls select JK-BMS as battery monitor fix not auto.
You state using DESS.
Where are your loads connected? AC_out only?
Do you have a connected grid meter?
What is your SOC?
Are you importing/exporting energy while charging 31W?
Are you drawing energy from battery, while MPPT is limitied .
Do you permit exporting to grid?
What is your buy price vs sell pricse?
Thanks for the input. I tried to increase the voltages in the MPPT in effort to get the MPPT not limiting power due to voltage (even though based on the values it should not have been the case). Have to see about the BMS setttings. The electrical layout is a bit funny in this system. There is VM-3P75CT monitoring the AC input on the house grid connection. Multiplus setup is such that there is no loads connected to the output. All DC (Solar included) should be pushed to input. This setup did work better before but then the BMS had to be changed and since then the solar output has been very very limited. I have to go over the BMS settings once I get in bluetooth range of the BMS. BMS parameters say now that CVL is 53.6 but the battery is full at the moment (forced with setting ESS mode to “keep batteries charged”). I did change the BMS statically set to JK-BMS, no help yet.
In VRM dashboard I see Load side correctly what VM-3P75CT is seeing. There is load (2-3 kW right now), battery is full but energy price currently is such that discharging battery is not sensible so not using battery is fine. But why is not the solar power being used?! MPPT output is now 0W (panel array voltages are OK, but 0 amps drawn). Obviously battery can not be charged but Mupltiplus should still be able to use the MPPT for AC load (in other words pushing it out from AC IN)… Is it possible to control MPPT output via NodeRED? DESS logic is doing some strange things so I’d rather use our own DESS logic to maximise economic return of the system…
