I just had a strange situation on a lithium setup. Some details:
600 ah total with 3 x 200 ah Relion Lithium batteries.
BMV 712
MMPT 150/100 with 775 watt solar.
Only currently charging via solar.
The batteries were at approx 67% then 1/2 hr later it shot up to 100% with 14.2 voltage. I can typically increase 15-20 on a good sunny (located in Florida).
What is concerning is the voltage jumped up very quickly and the BMV detected the voltage to equal stuff off for bulk. Typically this in conjunction with the aH being increased to almost equal 0 or 100% full. This did not happen until the batteries were significantly lower than the normal minimum of 75% - 85% per day. This happened some time ago when the batteries dropped to approx 60% but I thought I was missing something.
I have attached a graph from the portal to help show the inconsistent behavior. Any ideas what would cause this to happen? No settings, installations, etc have been done in approx 8 months. As you can see per this, it was able to charge without the necessary watts from the solar. 
