Good morning, I recently purchased my first Multiplus 24/800/16 with Cerbo GX and SmartShunt. I connected two 50Ah 24V Lifepo4 batteries in parallel. Everything worked fine until the batteries reached 100% charge, at which point the inverter no longer goes into float mode with the orange LED flashing, but remains with a solid orange LED and then generates a High DC Voltage alarm and disconnects the AC output. Sometimes instead of the High DC Voltage I see High DC Ripple Warning. I tried changing the Absorption and Float values with VEconfig, but the problem persists. I tried replacing the batteries, but the problem persists.
For clarity, I use the inverter as a pure UPS, so connected to the AC and when AC input is missing, it uses the batteries to power AC output, without solar or other systems.
My battery is Batteria LiFePO4 24V 50Ah litio-ferro-fosfato 50A BMS 1280Wh code: LS24050C
In VEconfig, in the Inverter tab I set DC input low shut-down = 21V, DC input low restart = 22.2V, DC input low pre-alarm 24V, while in the Charger tab I selected Battery type: LiFePo4 and therefore absorpion voltage is 28.40 and Float Voltage is 27. I noticed that if I set absorpion to 27 and Float to 26.6, it no longer gives the High DC Voltage alarm, but the battery does not charge more than 86%.
Sounds like one cell goes high volt and the bms cuts charging. During initial charging, or infrequent full charging one cell will always reach peak voltage first.
You could set your charger to 27.6v for both asborp and float for a day. That will give the bms some time to sort out the high volt cell.
The next day bump the absorp and float up to 28v for a day.
After that you can set the charger to the batt manufacturers recommended settings.
Cell balancers need time to bleed of excess cell energy / voltage.