I read mine when there is not any additional power draw other than the things I can't turn off. If I have a fully charged battery (single 24) all the lights on my panel are lit.
If I turn on several lights and check the monitor, it's usually one less light showing.
If I turn those lights off again, the monitor will be back to fully lit.
If I leave the lights on for awhile and have used other 12v power the monitor will show less lights respectively.. If after nothings been on for awhile and I check the monitor and it's down a light or two, I know I need to charge the battery...
I think what I'm trying to say is that I check the monitor when the battery is at 'rest' and hasn't any pull from it for a little bit... ;)
Just how I do it... No idea if that's how it works or not, but that seems to give me the best measure for my little brain to work with.. :)
Good luck!
Mitch
