Quote:
Originally Posted by LouMan
my thoughts exactly boydfoose,
I was wondering how you calculate the amphours on a battery if it dosn't tell all the data?
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how do you calc the ones that says the amp hours but dont say what the draw is?
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I'm interested if there are 'rules of thumb' for estimating amp-hours on used or new batteries, or perhaps a test you can run at a couple of discharge rates to estimate usable amp-hours - there seem to be so many variables in manufacturing (or in how they were used by the previous owner) that affect what current you'll get, and for how long ...
Even when the amp-hours are listed on the side of the battery, that's now what you get out of them. In my example I have a couple of (very used) 100 amp-hour 12V cells that will give me about 15 amp-hours at a 30 minute rate, 30 amps for 30 minutes. You can't do that sort of test in a store or at an auction before buying them. Is there a short test you can do to get a reasonable estimate?
thingstodo