Simple way to measure coach battery capacity
I'm looking for a reasonably simple way to measure the current capacity of the single coach battery in my newly purchased (used) RV. I have a basic voltmeter which I don't think will be much help, ...
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When we are camping off the power grid I just watch my homemade three meter BATTERY MONITOR panel (Two 12VDC Meters and one 75 DCAMP meter). My meter panel looks similar to this drawing for my Battery Monitor Panel
When the battery bank DC voltmeters drop down to the 12.0VDC level I can assume this is pretty close to being 50% charge state. This is not absolute but close enough for me. I will either start my battery charging routine or disconnecting the batteries from the system.
In my case I have planned all of this out and I usually see the 12.0VDC 50% charge state at 8AM each morning when I would normally charge up my batteries to their 90% charge state using smart mode charging techniques...
With my 255AH capacity battery bank we can run 22AMPS DC current from 6PM to 11PM including the parasitic drain and make it through the one day/night run off the batteries and just be at the 50% charge state at 8AM the next morning. We run all the 120VAC items we want to run from a PSW INVERTER and the 12VDC items direct connected to the battery system.
Then recharge the batteries during breakfast the next morning starting at 8AM in a three hour generator run time when allowed which will make us good for the next day/night run off the batteries.
This is how we do our camping off the power grid runs...
Roy Ken
When the battery bank DC voltmeters drop down to the 12.0VDC level I can assume this is pretty close to being 50% charge state. This is not absolute but close enough for me. I will either start my battery charging routine or disconnecting the batteries from the system.
In my case I have planned all of this out and I usually see the 12.0VDC 50% charge state at 8AM each morning when I would normally charge up my batteries to their 90% charge state using smart mode charging techniques...
With my 255AH capacity battery bank we can run 22AMPS DC current from 6PM to 11PM including the parasitic drain and make it through the one day/night run off the batteries and just be at the 50% charge state at 8AM the next morning. We run all the 120VAC items we want to run from a PSW INVERTER and the 12VDC items direct connected to the battery system.
Then recharge the batteries during breakfast the next morning starting at 8AM in a three hour generator run time when allowed which will make us good for the next day/night run off the batteries.
This is how we do our camping off the power grid runs...
Roy Ken
