[Shop-talk] Quick charger question

[Randall]

---- eric at megageek.com wrote: 
> I have a rechargeable flashlight with a 6V6AH/20HR battery.
> 
> What size charger should I use on it? (I'm assuming it's 6 volt, but what 
> amp rating should I use?)

Any idea what battery technology it is?  I'm guessing it's lead-acid AGM.  In which case you really want a 3-stage charger that will supply a "bulk" charge of about 2 amps until the battery voltage reaches about 7.45 volts (ideally corrected for temperature), then hold the voltage there until the charge current drops below about 42ma, then let the voltage drop to 6.9 volts (again corrected for temperature).

But you can pretty much get away with a charger that just holds 7.45 volts (at up to 2 amps) and then unplug it after 8-10 hours.  If you forget and leave it though, it will shorten the battery life.

Randall