How to keep spare batteries charged?

Old 07-13-14, 02:16 AM
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How to keep spare batteries charged?

I have a couple of these spare batteries that I'll be using later on when the current batteries lose capacity to hold a full charge. But I've been keeping these spares around for a few months now and I think batteries need to stay charged or like to stay fully charged? I'm worried if these spare batteries lay around near empty for a year or longer, it may shorten the life of these "new" spare batteries.

How can I keep them charged? I see they have open ended positive and negative wires. Can I just connect them to a AA battery and charge them? Or do they need to be connected to an adapter plug that can be plugged into the wall socket?
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Old 07-13-14, 07:55 AM
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Batteries will lose their charge over time. If they are spares for later use, they should be left in their mostly uncharged state. Charging them all the time will shorten their life more that leaving them alone. Just store them in a cool dry place.
Old 07-14-14, 10:42 PM
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Oh? I didn't know this. I was sure I read that it was BAD to leave a battery empty for long periods of time because then they may not be able to hold a full charge again. So you're saying it's better for me to just leave it near empty? I have conflicting im confused haha. But thanks for your advice. I'll definitely keep that in mind.
Old 07-22-14, 10:15 AM
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Can you alternate the batteries? NiCad and NiMH batteries like to be fully cycled and do not handle short usage and constant charging well, If you can charge one set and use the other until it is drained, then swap, you will extend the life of both sets of batteries. Unused batteries whether full or empty will slowly crystalize and lose capacity -- even in an unopened package batteries will lose capacity over time
Old 07-22-14, 11:00 AM
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Well, as someone who had to deal with batteries every day in my previous life, it depends on the battery. (Real helpful there, huh?) If they are NiCad or NiMh as mentioned, they should be charged fully and then checked every few months. Not daily or weekly, but at least every 30-60 days. NiCads are the worst, because they can just crap out with no warning. NiMh are much more forgiving of sitting for a while. My 6 y/o cordless phones use NiMh and I just replaced 3 of them because talk time had finally dropped to maybe 45 min (wife and sister like to chat for hours and hours) where they used to be 1 1/2 hrs.

I had to replace my NiCad tool batteries (stored in the garage) after only a few years because they just wouldn't hold a charge more than a few days. I bought Lithium ion replacements, but even an older set of those I had only lasted about 2 yrs with weekly use.

My opinion is to charge what you have, let them sit, but swap them into the equipment every 6 months or so. If I'm reading the date code correctly, they are already a year old.

We used to store lead acid and alkaline batteries in a fridge to slow the chemical reaction. Not sure how that would work with new formulations. Cool and dry is whats always recommended.

If you let a battery get below a certain voltage, it just won't be the same again unless you have a smart charger.

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