I had a fairly long logging session recently that logged DC V while charging a 12V battery. I left it on the default logging rate, thinking that was once per second, but it turns out that my meter defaulted to "0", so according to the manual was actually logging at the fastest rate of around 200ms.
Around 25-26 hours later I went to the meter and saw a voltage of around 13.67V. My victron BMV-712 told me that current down to nothing, so that was as far as the charger was going to take it. I stopped the logging, and the beginnings and end of the log file look like:
START,2018/04/24,16:45:07,
ID,170800000,
INTERVAL,000,sec,
,MAIN,,,SUB-1,,,SUB-2,,,Remark,
No. ,Func. ,Value,Unit,Func. ,Value,Unit,Func. ,Value,Unit,
1,DCV,013.182,V,,,,,,,,
2,DCV,013.188,V,,,,,,,,
3,DCV,013.187,V,,,,,,,,
4,DCV,013.187,V,,,,,,,,
5,DCV,013.187,V,,,,,,,,
6,DCV,013.187,V,,,,,,,,
[cut]
364219,DCV,013.529,V,,,,,,,,
364220,DCV,013.530,V,,,,,,,,
364221,DCV,013.529,V,,,,,,,,
364222,DCV,013.530,V,,,,,,,,
364223,DCV,013.529,V,,,,,,,,
364224,DCV,013.529,V,,,,,,,,
364225,DCV,013.530,V,,,,,,,,
364226,DCV,013.529,V,,,,,,,,
MAX,67374,DCV,013.531,V,
MIN,1,DCV,013.182,V,
Something is very odd here. The last sample was 13.529V, and the max was recorded as 13.531.
I am not sure what happened here. It doesn't help that the meter only logs sample count, and not time. If I really assume that it took a sample every 200ms, then the meter only logged for a little over 20 hours. But I know that I stopped it a minimum of 25 hours later. So, OK, 200ms is approximate. So maybe its is more like every 250ms on average...that would work out to a little over 25 hours (after 364226 samples).
But if it really was logging up until the point that I stopped it, then why were there no records of the 13.67V readings that I saw on the display (and was also reported by the Victron BMV-712)?