I have a BMV 712 monitoring my two 100 Ah LFP batteries wired in parallel in my RV for about 3 years now. Recently, I have noticed that the SOC will reset to 100% for no apparent reason. This month, I purposely fully charged the batteries, synced the BMV and then ran the batteries down to 90%. I disconnected all routes of charging (solar, alternator and shore) and watched it for several weeks. During that time, it stayed at 90% until one morning I checked it and it was at 100%. I have the unit programmed to “Keep SOC” on reset. I have tried swapping the shunt with another BMV and see the same confusing results. Any ideas would be appreciated.
Ypu might find the battery is randomly disconneting output and it is resetting to 100%
What absorption voltage do you charge at on your chargers and what is the “charged voltage” set to on the BMV.
I was kind of thinking it may be the built-in BMS on the lithium batteries, but am not quite sure how to confirm. I just upgraded to 4 new 100 Ah batteries. We’ll see if the problem persists.
If it is a Bluetooth capable BMS it may record the number of disconnects.
I have the charged voltage set to 14.2 and the AC-DC charger in the RV is set to 14.6.
Unfortunately, these are 9 year old batteries and do not have smart BMS, but the new ones do. What is curious is that this is a fairly recent phenomenon. Up until recently, the BMV worked as it should. I plan on putting it though some testing this weekend.
Those voltage settings look good so should not give synchronisation to 100% without proper charging occurring.