I bought a BMV 712 smart battery monitor, I connected it to my battery bank which consists of 16 Trojan 105 flooded lead acid batteries (6V-225ah) in a 4x4 configuration. The problem that I'm having is that during the morning the SOC of the battery bank jumps from, let's say, 90%, to 100% in just a monent, as soon as the voltage from the charge controller gets high enough. How can I fix this? I thought that maybe it has something to do with with the max charge voltage, which I set up at 26.4V.
The BMV712 uses the Maximum charge voltage to figure out when to reset itself to 100% charge to prevent synchronization issues inherent with amp-counting meters.
The voltage starts to rise in the AM and the "sych" conditions are met as soon as the voltage exceeds 26.4 while the current is less than 4% of the battery capacity.
See this part of the manual:
The BMV synchronises too early
In solar systems or other applications with fluctuating charge currents, the following measures can be taken to reduce the probability for the BMV to reset prematurely to 100% state of charge:
a) Increase the “charged” voltage to only slightly below the absorption charge voltage (for example: 14.2V in case of 14.4V absorption voltage).
b) Increase the “charged” detection time and/or decrease the tail current to prevent an early reset due to to passing clouds.
See section 4.2.1 for set up instructions.
Mine does the same thing. Usually around 93%. I've noticed though that it does this after I've hit the top of the absorb phase, 14.4 for me, and it's on its way back down to float, 13.6 for me. Not when it just got to 13.6 This has also gotten better over time so I don't think it's something you need to worry about right away. I think the more it synchronizes the better it gets.
