I am having an issue I can't quite figure out. I have (2) Multiplus II 48v/3kva in a split-phase 120v/240v arrangement. I have a temporary battery bank installed consisting of (4) 12v 100ah AGM batteries wired in series for 48v. I have set the system to "Charge Only" with a 50A grid current limit so I am effectively bypassing the inverters. When drawing more than 3k watts per leg from the grid, the battery bank voltage spikes over 60v.
Why is this happening?
Check your dvcc max battery voltage setting. And your essential settings. Please add some screen shots of your master inverter setup . Remove any bms system settings. In your assistants.
I am presuming you have removed a set of lfp batteries and add a set of agm batteries.
Also as much info about your setup and what's connected.
DVCC max battery voltage is set at 59.2v
Float is set to 55.0v (13.8v per battery)
Absorb is set to 59.2v (14.8v per battery)
ESS is the only assistant configured
This is a new setup so all battery settings are configured for AGM, there are no LFP specific battery settings or BMS settings as these are "dumb" AGM batteries wired in series to provide 48v until I purchase my LFP rack battery bank. Batteries have been in float and inverter is not being used to power loads - I am strictly passing grid power through to power loads for now.
Setup is as follows (2) Multiplus II 3kva in split-phase backfeeding a sub-panel via a 50A dual pole breaker. Grid is connected via a 50A dual pole breaker directly to each Multiplus. The sub-panel powers lights, a hot water heater, washer/dryer combo, mini-split, and some electronics in a small shed.
VE Bus voltage can be totally different to battery voltage especially if it is processing alot of power. Even with it "bypassed" the power is still pouring through the bus.
If you had a shunt you would be able to compare the two different readings.
