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Discussion Starter · #1 ·
The Battery Tender I have is .75 amp. It takes forever to top off my 2 Deka 850 CCA batteries in my race car after racing a weekend. . What would be a better maintainer? The car does have a 100 amp Powermaster alternator. I do not charge at the track.
 

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Stanley Battery Charger with Engine Start (BC25BS) (solidsignal.com)

I have this exact charger that I use at the track and at home to keep my battery topped off in my car. I do run an alt. on the car so that also helps. It has a recondition function that I have revived some old batteries with. I have had it for about 5 years now. Has worked pretty good. I only paid 50 bucks for it at Wal-Mart. I have a regular, old school 100A charger for quick charging. If you need a charger at the track and do not run an alt. you might need something with a few more amps in between passes depending on what you are doing.
 

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Low and slow is better for battery longevity, so I use this all purpose AGM charger



It's dirt cheap and works great for charging and conditioning all types of batteries

That being said, if you have both batts connected in parallel, keep in mind that you'll have to isolate them or they will feed off of eachother and self discharge
 

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Discussion Starter · #4 ·
"That being said, if you have both batteries connected in parallel, keep in mind that you'll have to isolate them or they will feed off of each other and self discharge"

i have not heard of this before. I have had 12 volt batteries in parallel in race cars for ever and have not noticed any excessive drop in voltage.

I am concerned that my 2 batteries in parallel take a long time to turn the charge light from red to green on my .75 amp charger/maintainer. Just wondering if a larger capacity one would be any better.
 

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If the two batteries are matched well, you won't notice much of a drop.

Thing is, no two batts are perfectly matched, so there's always a voltage difference.

If one batt has 12.6 volts and the other 12.4 volts, the one with more voltage will feed the lesser one until they equalize.

As either one starts to lose voltage over time, they will continue to feed off of eachother.

This is why flashlight batteries are usually stacked in series rather than being wired in parallel.
 

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I've ran 2 batteries for years I mean like 20+. A 1.5-2 amp charger will maintain them. But if you let the car set without a maintainer on it disconnect the batteries from each other. They will "tictoc". As mentioned they will never have the same charge. The lower one will suck of the higher one and become the higher one, then the same will happen again and again until they are both DEAD. I am currently using this charger and like it.
 

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