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Old 07-18-2012, 10:06 PM   #2 (permalink)
mort
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Quote:
Originally Posted by SmellyCat View Post
Hello again, Here is the question. I have a dead battery, 550 amp battery, how long would I leave it on a 10 amp charger. Safely. Thx sc
hi SmellyCat,
Very roughly - assuming that 550 is CCA, the number of amps the cold battery can deliver for 30 seconds before the voltage drops so low that the engine won't start (7.2 volts) - so 550/10 is 55 and 55 X 30 seconds is about 27 minutes.
But this all depends on the charger. If it truly delivers 10 amps regardless of battery condition, figure about a half hour. If it delivers a maximum of 10 amps and tapers off as the battery charges, then figure an hour. If the charger tapers off to below 2 amps, you can leave it charging all day and not hurt anything.

-mort
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