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, ...
Forum Discussion
landyacht318 wrote:
Draw it down 50% of the original nominal capacity at the rate at which it earned that capacity and wait for voltage to rebound.
IE if it were rated 100AH at the 20 hour rate, apply a 5 amp load for 10 hours, remove the load, and wait a few hours for voltage to rebound.
If it rebounds to 12.2 or so, then the battery is still healthy.
By no means a perfect capacity test, but on a single battery of unknown age and condition it will give you a general idea.
Other than inaccuracies in how close one was to applying exactly 5 amps, how close one was in timing for exactly 10 hours, and how close one was in measuring the ending battery voltage .... why isn't this a "perfect method"?
It sure looks brilliantly eloquent in it's simplicity to me. The only reason I can see as to why battery shops couldn't/wouldn't use it is the time it takes to perform it while the customer is waiting!
If someone can explain what I'm missing here ... please do so.
