I'm running a Multiplus-II 2x120, SmartSolar MPPT, Cerbo GX, and a new pair of Ampere Time 200Ah batteries with built-in BMS. I had been running three 100Ah Battle Born batteries before and saw something similar.
Today is the second day with the new batteries, so I specifically set the ESS parameters to fully charge the batteries. Exactly as the batteries reached the default absorption voltage of 14.2, the system "crashed" flashing the Overload and Low Battery LEDs. This happened yesterday morning as well when I was first starting the system after the batteries were fully charged using an external charger. I should add that there has been abundant sunshine and solar power both days and the SmartSolar was delivering significant power.
My theory is the batteries reach the threshold to switch into absorption and the system -- not sure which part -- creates a brief voltage spike (I've seen it over 15 volts using a meter) when switching into absorption. The battery's built-in BMS detects the excess voltage and disconnects resulting in 1) the low voltage warning in the log (resolved in 3 seconds) followed by 2) the DC ripple shutdown.
My question, assuming the system voltage spike is indeed the primary cause of and can't be eliminated, is how best to prevent this in the future. I'm running an ESS Mode 2 program, so I can program the system to not fully charge the batteries, but it just seems like there should be a better solution.
Suggestions?
TIA
Jim