I have a BMV-712 which monitors the state of charge of an 800 Ah lithium pack. This is installed on a liveaboard boat and is charged purely from solar. Day to day the soc remains within the range 30-80% and is in continuous use. I recognise the issue of drift and as a result each month I bring the soc up to calibrate the BMV back to 100%. I have the reset conditions quite tightly controlled, the BMV needs 13.7v (absorption at 13.8v) and a 2% tail current for 6 minutes. This reset always occurs ‘prematurely’ ie at an indicated soc of about 92%. I know I cannot avoid soc drift; however, for it to be consistently in one direction makes me believe the situation can be improved by changing my settings. Since, at the end of the month the BMV is underestimating the true soc I felt that I need to increase the charge efficiency factor. I already have this set to 99% and changes are only available in whole numbers. Could I ask that you confirm my logic and if I am correct is there any chance we could get a software update to introduce more precise settings for the charge efficiency factor?
