I'm a newbie with a pretty basic question. I've got three Victron batteries in my van and, after only using lights and a fan for three days (no A/C, stovetop, or water pump) the Victron display shows my batteries at 24%. My installer says to ignore the 24% and instead look at the voltage of each of the three batteries (which are each at around 11.5 volts, after each starting at around 13.7 volts after being charged). So, do I have 24% remaining in my batteries or closer to 83% (11.5 divided by 13.7)? Thanks!