Following the interesting post about Li-ion batteries, I'll write a bit about a new type of battery in the NiMH area.

NiMH (Nickel Metal Hydride) is the most popular solution for rechargeable AA / AAA batteries (1.2 Volt). In recent years, these batteries got better, and competed on the "who has a bigger" mAh (Milli-Amper-Hour) category, which measures the batteries' capacity. 2700mAh is the biggest number I've seen yet in stores.

One of the disadvantages of NiMH batteries is their quick self-discharge: within few weeks, a 100% loaded battery would self-discharge to 50% state, regardless whether it's been in use or not.

The new NiMH variant is called Low self-discharge NiMH batteries. These ones are supposed to self-discharge much slower: After a year, a 100% loaded battery would self-discharge to 70-85% (compared to 50% after few weeks(!) with regular NiMH, as mentioned in previous paragraph). A nice side-effect is that it also comes partly charged from the stores.

GP ReCyko is one brand, so far the only one I've seen in Israel. I bought 4 AA such batteries for 80NIS ($22). I'm sorry that it looks like an ad, I just don't know any other brand yet. Actually these batteries are only 2050mAh (written in really small letters), but still, it's 2050mAh that stay longer..

The big advantage of the new type of batteries is for low-profile consumers, such as remote controls, clocks, calculators, or my bicycle led flashlights; for in these appliances, the main factor for discharging is the self-discharge, and not the appliance's regular electricity consumption.

So, is it really greener as the ad says? Probably yes, for two reasons:

• Now we can use a rechargeable battery for more-or-less all appliances.
• In many cases we'll recharge the batteries less frequently, thus power plants could rest more.

So.. stop buying single-use batteries that ruin the environment.