Battery voltage checking

While camping, there is always a little load, so you check it when there is the least load, and also before sun-up if you have solar, because solar charging cranks up the voltage.

I call it the "morning voltage" which I check before sunrise and without the furnace being on just then, and no lights or fans either.

It is not the purist's idea of "resting voltage", but it is "close enough for camping work"

All you need it for is to decide if you need to do a recharge that day (if no solar). Say you are out for a few days and the first morning it says 12.5 and next morning it says 12.3 so you expect the next morning after that it will be 12.1 and it is. So you can see the battery specs say 12.1 is 50% and you anticipate tomorrow it will be 11.9

So now you say oops I must recharge today or else it will go below 12.1. Only thing is today you have scheduled to go somewhere away from the rig so you can't be there to do the recharge. Has to wait till the day after. But no problem! You saw this coming, so you did the recharge the day before when it was only down 60% at 12.3 :)

Your "morning voltage" is close enough to make your decisions while camping, and once you get home you can charge the batts up fully to 100% and "baseline SG", then put them on Float till the next time camping.

If the chart says 10.50 volts is discharged... that would be 5 to 25 amp load.

If the chart says 11.89 is discharged... that is disconnected (no load) and resting for 24 to 48 hours.

The 12 Volt Side of Life

At rest. The longer the better but 15 minutes will be close.