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Old 08-20-2012, 02:46 PM   #10 (permalink)
christofoo
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00C - '00 Toyota Corolla
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Quote:
Originally Posted by ecomodded View Post
I would switch it out also, all that charging will hurt your mpg and your alternators life span.
While charging the battery should read the same voltage as the chargers output so i am unsure why it read 14.5 volts earlier in its life if on the same charger, could be a indication of a dying cell.
I just started using a desulfating charger. (BatteryMINDer, bought it on Amazon.)

My results might not be definitive, but I believe my 2 batteries hold a charge better, and the charging asymptote has gone down. I.e. it was 2 A previously, now it is ~0.5 A.

FWIW, I don't change a battery until the starting gets weak. One of my two batteries was beginning to get weak before the desulfating charger. It "seems" a lot stronger now. This is cheaper than 1 battery, probably more environmentally friendly, and will ultimately save the cost of many batteries (assuming it works, which I probably can't say definitively for a few more years).

I wasn't clear on the testing method here, but the asymptotic charging current is a better test than the asymptotic charging voltage. I.e. run an outboard charger overnight and check the current in the morning. If the asymptote is high it will place a waste load on the alternator which will have a very small effect on MPG. I.e. ~30W for 2A, or probably 0.3-0.5%.

(Also as was pointed out, the battery is not likely the culprit on idle speed.)

Last edited by christofoo; 08-20-2012 at 03:00 PM..
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