by Socal Tom » Mon Apr 26, 2021 9:13 am
Top Left is voltage, gives you a general idea on state of charge of the battery anything over about 12.6 volts with no significant amp draw is pretty close to full charge
Top Right is instantaneous amps moving through the system. On the demand side, its how much is being pulled out of the battery at that moment, on the supply side its what is going in the battery at that moment. ( generally this means that if solar is making 7 amps, and the fridge is using 3 amps you will show 0 demand and 4 supply)
Bottom left is instantaneous watts essentially the same as the top right, but watts instead of amps ( watts =amps x volts)
Bottom right is the cumulative watt hours used. This totals up the watts that moved to or from the battery since the last time it was reset.
If the watt hours supplied are greater or equal to the watt hours used, then your solar panel made up for more than you used ( due to efficiency losses you expect a full charge to be about 10% more watt hours supplied vs used)
If the watt hours supplied are less than the watt hours used, then your battery has been depleted somewhat.
My batter is an 85amp hour battery, to estimate total watt hours I multipled 85 amp hours x12.5volts ( I'm not going to explain why I used this number, it will add confusion here) so I ESTIMATE that I have about 1062 watt hours in the battery. Since I want to stay above 50%, I want (watt hours used - watt hours supplied) to be less than 531 watt hours.
I generally reset my baylite meters once I unplug for a trip. The lowest numbers are usually in the morning when power has been used all night, I use between 200 and 400 watt-hours over night. By sunset ( when solar stops charging), I've usually put back slightly more than I used so I consider the battery fully charged.
-Note- This thread is about to get spammed by some people that will tell you my estimates are wrong and argue about the exact voltage and a bunch of other stuff. I shared how I interpret these things, and I believe most of us weekend warriors will find my method to be good enough for our intended use.
Tom
note I should add, once the battery is near full charge, your charge controller limits the power sent to the battery, so don't be concerned if you are in full sun, with a full battery and its not reporting very many amps or watts being sent to the battery.