One of our customers has an RV with a MultiPlus 12/3000 installed, and 4x Battle Born 100Ah 12V lithium-ion batteries in parallel. The only charging source at this time is shore-power.
She reports strange behavior when the MultiPlus goes into absorb; the lights flicker, fans beep due to under-Voltage and such. I had her measure the Voltage while charging and it was in the high-15V range, touching on 16V at times!
The DIP-switches on the MultiPlus are all set to "off" which would mean the absorb Voltage is 14.1 Volt, and there is no temp-sensor attached (so not temperature compensation, as it should be for lithium-ion batteries). Very likely the BMS in the batteries is switching off due to over-Voltage, and that's causing the effects she's seeing with the appliances.
The question is: What could cause the MultiPlus to exceed its set absorb Voltage of 14.1 Volt??
Pictures of the install are attached (and no, there are no solar panels installed yet, despite the SmartSolar in the picture, so that charge controller is doing nothing).
Thank you for your help!