I installed a new system, mainly consisting of a MultiPlus 12/3000/120, VE.Bus BMS and 4 Smart Lithium 12.8/100 for a total of 400Ah.
Multi firmware is 2600430. Charger set for Lithium and Lithium Assistant is set up and started.
After letting it run for 24h discharging with small loads, today I connected shore power to see how the system is performing with AC In connected.
Charger went into Bulk, charging with 50A until after some time 14.2V was reached. Then it switched into Absorption as expected. Charging amps slowly decreased, which I think is ok. But then also the voltage started to drop until about 13.84V. Charger then switched into Bulk again, charging current starts to increase until 14.2V is reached. Then the whole process starts all over again, This all happens within minutes. See images attached.
I would expect the charger to stay in Absorption for 1h as it is set for with VE.configure.
So I feel there is something not working as expected.
Any help much appreciated.
edit: additional info - the moment absorption is reached, the BMS red LED comes on, which means either high voltage disconnect or temperature. Battery voltage is around 14.2V when this happens. None of the individual cells are anywhere near 4V nor is the temperature exceptionally high.