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jmcgsd's avatar
jmcgsd
Explorer
Jun 01, 2014

I know, a full battery reads 12.8 open circuit but ...

Ok, there are graphs galore that show open circuit voltages for condition vs voltage. My question is: "What readings do you see on you panel with a moderate load?" Let's say you're boondocking...
KD4UPL's avatar
KD4UPL
Explorer II
Jun 01, 2014
Your question proves the fallacy of trying to use battery voltage to determine state of charge. It varies all over the place based on load, temperature, state of charge, etc.
If you really want to know what condition your battery is in you need a battery meter (not a volt meter). Battery meters use a shunt to measure the current into and out of the battery. Tri-Metric makes a nice one. So do Victron, Outback, Magnum, Xantrex, and Blue Sky.

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