The Sustainability Review: Rechargeable Batteries 

We use a ton of rechargeable batteries here at our house. They power headlamps, mp3 players, testing equipment, and a variety of kid toys. They have many applications and it can be to your advantage to use the right battery and charger to get the best results.

Why should you use rechargeables versus cheaper disposable alkalines?

Alkalines are:
• more expensive in the long-run because you buy so many more of them
• disposable and create a significant amount of toxic waste (our recycling center recently stopped recycling them so that route of disposal isn't available locally)
• don't perform any better in almost all devices

I think that rechargeable batteries have been given a bad name by the original rechargeable, the nickel cadmium battery (NiCD). There are three reasons I think they rightfully have a bad name: 1) They are extremely toxic and must be recycled, 2) they develop a memory, and 3) their capacity is much less than the alkaline. We had these for years and they were unreliable and difficult to deal with.

What should we use then? The nickel metal hydride (NiMH) has been around for years and is a great choice, especially with the advent of the newer ultra-low self discharge (ULSD) varieties. What is so good about them? They are an affordable, non-toxic, good performing battery.

There is a newcomer on the street that may just revolutionize the NiMH world. It's the ULSD battery. Through some fancy technological feats, several companies have created a NiMH battery that doesn't self-discharge much and comes ready-to-use. I think the alkaline battery folks are quivering in their boots. I recently purchased several AAAs and am impressed with their performance. They cost nearly twice as much but being able to leave batteries in something and have it not lose charge is a huge plus. They can sit for 6-12 months and lose less than five percent of their charge.

Here are my suggestions to treat your batteries well so they will have a good, long life.
1) Buy the highest capacity battery you can find. You'll be happier in the end because they last longer and are more comparable to an alkaline. Look for 800-1000 mAh AAAs and 2200+ mAh AAs. I buy my AAA batteries for about $1.75 ($2.75 for ULSD) each and they last several years of regular use.
2) Buy a “smart charger.” These chargers enable various methods to determine the battery’s state of charge and charge accordingly. They won't damage the battery by overcharging it like many older chargers can. Do not use your old NiCD charger unless it says specifically that it will work with NiMH batteries. A good smart charger that can recharge four batteries at a time should cost between $20-40.
3) After your batteries are charged store them in the freezer. One drawback to NiMH batteries is that they lose about 40 percent of their charge in a month at room temperature. You can reduce this to approximately five percent in the freezer. Allow them to reach room temperature before using. No need to freeze ULSD batteries since they don't self-discharge.
4) Periodically discharge them completely. Even though there are claims that NiMH batteries don't develop a memory, they can develop a small one. It's easy to allow your flashlight to go completely dead before you replace and recharge the batteries.

There are many local stores that offer rechargeable batteries and chargers. In addition I have found http://www.greenbatteries.com/ to be an excellent resource for products.

My purchasing recommendations:
NiMH batteries (standard): I have had good luck with GP, Energizer, and Tenergy batteries.
ULSD batteries: Eneloop and Hybrio consistently outperform all others in independent tests.
Chargers: Turbocharger 4000 available from greenbatteries.com for $24.95.

Mike is enjoying the long fall and mild temperatures.