Rechargeable batteries save money

We were at Job Lot the other day. Job Lot is one of those chains that buys up remainders and merchandise from business failures; we often find good bargains there.

I happened to be standing with my back to a display of batteries as a women several yards away was squinting in my direction.

"Are those double A's behind you?", she asked. I turned around and confirmed that yes, they were. "We use a lot of those", she added.

Sure. We use a lot of those too, but as cheap as the Job Lot price was, it could not compare to the economy of using rechargeable batteries.

Actually, we bought most of our rechargeables at Job Lot too, but that's almost unimportant, Rechargeable batteries can save you a lot of money even if you buy them at the most expensive source you can find. They may cost more than the disposables (though not necessarily) but they can be recharged many times.

How many times? That depends on the type of rechargeable - it could be as little as 100 times or many thousand - Wikipedia has a chart that details cycle life and overall life for different types of rechargeable batteries. Of course you would expect to pay more for the longer lasting types and you may need a specialty charger which can add to your total cost.

Recharging

When recharging, let the battery cool down first if you were recently using it. Apparently NiMH and NiCD chargers use temperature to judge the charge state; starting off warm could interfere.

Also understand that a "fact" that is true for one type of rechargeable is not necessarily accurate for another. For example, you often hear about only doing deep discharges. That's good advice for most AA batteries, but for the batteries we use in computers, it isn't: they actually do better being recharged earlier.

Eventually, these do wear out. I have a set of AA's I have used in my camera for three or four years and they have now become too weak for that use. However, they still seem to last quite a while in our TV remote, so I have not sent them off to recycling yet.

Lithium?

I see Energizer advertising a Lithium AA as having a 16 year storage life!

Lithium batteries have only recently become available in AA sizes. Some lithium are rechargeable, some are not. There are real dangers if any of these are put in a standard NiMH/NiCD charger - they could explode.

Some devices warn against using them; I find this whole area very confusing and I avoid these because of it. If anyone knows of a good, current link that fully explains lithium AA (or AAA) batteries, rechargeable and not, please leave it in the comments and thank you!

Recycling

Please do recycle all batteries. Rechargeable batteries can pollute landfills even more than disposables, and those are bad enough. There was no battery recycling drop-off in this town when we moved in, so I just saved them up and took a pile to my daughter because her town did offer this. Please do not just carelessly toss these in the trash!

Update: More recently I've read that you don't need to recycle alkaline batteries. As the comments at that link discuss, that's a bit disturbing.

Charge loss

Rechargeables lose charge just sitting around, but different types lose more than others. The lowest are LSD (Low Self Discharge) NiMH, which lose less than 15% in a year (ordinary NiMH can lose 4% per day or more).

Lithium batteries can lose so much charge that they cannot be recharged. I learned that the expensive way! If you have bought a spare battery for your computer, don't just tuck it away and forget about it!

Mixing batteries

You don't want to mix old rechargeables with new. Some people mark a date on them with a Sharpie, but I just keep matched pairs together with a rubber band while they are waiting their next turn in a gadget. When they do become too weak for reuse, I recycle the pair. Obviously you definitely would not want to mix different types.

9 volt

I have never seen 9 volt rechargeables at Job Lot, but they are available.

We only use 9 volt batteries in smoke detectors, which we replace once a year. It would not be a good idea to replace these with rechargeables because of the discharge problem, but it certainly would be more convenient. I also always feel a bit guilty recycling a 9V battery just because it is a year old.

I do see a 9V 200mAh Low Self-Discharge NiMH Rechargeable at Amazon, but I am a little hesitant to try it. Again, if anyone knows of a good link on using these in smoke detectors, I'd love to have it.

Very much worth using

I would have liked to have told that woman all this, but there wasn't time for that. I did briefly mention that the rechargeables (which were also in the same shelf) could save her a lot of money, but I don't think she took that advice. People tend to look at the initial cost of the batteries and the charger and not realize how quickly that goes away from recharging savings.

Admittedly, there is lingering confusion in some areas, but overall we know we have saved a lot of money in our camera, clocks, remote controls and other devices.

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