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Saturday October 10, 2009

Are Rechargeable Batteries Cost Effective?

Jeb sent me this article where the guy says rechargeable batteries are rarely cost-effective. Here's what I wrote back:

He's right to some extent, but it surprises me that he doesn't have a digital camera in his house. Those go through batteries pretty quickly and just about everybody has one. Though maybe he has one that uses a special battery instead of standard AA's. Flashlights go through batteries pretty quickly too if you use them regularly, though I think I've only had to recharge mine twice in the six months or so that I've owned it (that may go up as I take the dogs for walks more often at night with the shorter days). The Archos eats through batteries too, as do some CD players that people might use every day. At the store I see packages of 24 disposable batteries and I have a hard time believing that someone buying a package like that couldn't replace at least a few of those with rechargeables.


He is also missing the boat on Low Self Discharge batteries like Eneloops. These don't require a 30-60 day cycle because they can hold a charge for so much longer (a year or more). You can put these in a flashlight or camera you don't use that often and they will be ready immediately whenever you need it for over a year (they retain 80% of their charge for the first year). Plus a rechargeable like an Eneloop will take more pictures than an alkaline before it goes dead. However they cost a lot more than alkalines (or regular NiMHs which can lose half their charge in a month). I think I figured that Eneloops cost 7 times as much as an alkaline on sale. So you would have to burn through 7 alkalines, which would take many years (longer than you would own that item; though honestly you will just get something else to replace it that will also need batteries) in most remote controls, alarm clocks, etc.

Unless you can get the rechargeables on sale. I got the Duracell-branded Eneloops for $6.45 for a 4-pack on a really good sale. That cut the ratio in half. So I bought 8 AAA's and AA's and will use them in my network of indoor/outdoor thermometers and my remote control. Those are on roughly a 1-year cycle and so the Duraloops will pay for themselves in 3 years. After that I'm just raking in money.

Unfairly, this guy looks at an 18-month period. Is that how long he will own a wireless mouse? Maybe 3 years would be more appropriate. Plus he talks about the price of a charger being $40. But he needs a charger for the Wii system already, so that is a one-time cost. You can get an acceptable charger for $20 - $26 (charges batteries individually instead of in pairs, senses when the battery is full, and takes at least an hour or two to charge).

Where people mess up is in buying a number of chargers and I include myself in that group. I have something like 6 or 7 chargers that do nothing but charge AAA and AA batteries (including a Rayovac Renewal rechargeable alkaline charger that didn't quite pan out). Most of the ones I have are cheap chargers that charge batteries too fast and eventually destroy them (the vast majority of what is in stores). They are junk. Now I have a really good charger and shouldn't ever need another one.

People also mess up by not getting batteries on sale. Whether it is rechargeables or alkalines, there are good sales if you look for them. Walgreens had a not-all-that-uncommon sale where you could buy one 16-pack of Walgreens alkaline AA batteries for $10 and get a 16-pack of AAA batteries for free. 31 cents per battery. My Duraloops were $1.61 each (so that's a ratio of 5). But if you just drop by Kroger and pick up 4 Duracells not on sale you might pay $5 or over $1 each for a throw-away battery. I have way too many batteries now though.

98% of people aren't going to educate themselves enough to make a good decision on battery and charger purchases. They will just go to the store at any random time, buy a cheap charger with some cheap NiMH batteries and be disappointed.

Comments (1)

We use 3 AA's in our wireless keyboard and 2 AA's in our wireless mouse. Our Mac gets used so much, we probably swap them out once a month. There are always 4 AA's ready to go charged. They are not warm, and the charger says it is ok to leave them there.

My camera uses 3 AA's. I think we are saving money.

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