Quote:
Originally Posted by bennelson
Another thing I would like to look into is if there is some simple way to voltage limit a cheaper charger. For example, if I could simply limit the max out voltage of a 10 amp $30 charger, I could buy a bunch of those and use one each on all the batteries.
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You're thinking of the 10amp Harbor Freight ones, huh? Those would be good. I have 7 (8 actually) of the 6amp harbor freight chargers. They go up to 14.3 v, hold for awhile (until the battery is full?), and then drop down to 12.8 and hold it there for awhile, then jump up to 14.3 for a second, and then drop down to 12.8 and hold. All you need is to drop like 0.2 volts, but only on the high part.
Easy way: (would work until the battery is full, and when it drops to the trickle charge level of 12.8, this would still be OK! Because it wouldn't still be providing 10 amps to the batteries. It would be trickling at like 2 amps or less)
You could lengthen the cord, so that it would have a 0.2v drop built into it at 10 amps. Hmm...
0.2v = R*10amp
R = 0.02 Ohms. 14 gauge wire is 2.575 Ohms / 1000 feet. So, (haha! this feels really familiar!)
Length = 0.02 Ohms * (1000 feet / 2.575 Ohms) = 7.77 feet.
So, just add 7.77 feet of 14 gauge wire to each of the 10 amp chargers. When it moves into trickle charge mode, instead of 12.8v at 2 amps (or less), the extra wire would have a 0.2/5 voltage drop, which would provide a trickle charge voltage of 12.76v. That's fine! Maybe the trickle would be ever so slightly less trickly, but I think it would work.