Is this a scientific answer, or environmental?

"Which are better, NiCd batteries or NiMH batteries?

For most electronic devices it is better to use NiMH batteries than NiCd batteries. NiCd batteries use Cadmium, a highly toxic heavy metal, that can damage the environment if not disposed of properly. (They should be recycled not discarded). NiMH batteries usually have a higher capacity than NiCd batteries of the same size. Some people argue that NiCd batteries deliver faster discharge rates than NiMH batteries. While this may be true under certain circumstances, the difference is not relevant when considering power sources for electronic devices like digital cameras or portable music players. (If you are choosing a battery to drive a high torque power screwdriver, then NiCds can outperform NiMH). NiMH batteries require more sophisticated chargers than those typically used for NiCd batteries. But smart chargers designed especially for NiMH batteries are now readily available."

Link

I think in general, those comments are correct. Most electronic devices really do not pull that much current compared to the battery capacity, perhaps for the reason that consumers want more than 1 hour of use from most devices.

Each battery chemistry (and its detailed construction setup) has its advantages and limitations. Li based tend to have higher voltages, but less ability to delivery very high currents (and we are talking real amps of flow here, not normal electronics stuff)

IMHO, NiMH is the way to go for 90 + % of the applications when you are going to recharge the batteries. If you are going for primary cells (not recharged), use Li based whenever possible.

There are recharge type Li batteries, but only a few actually are safe to really use by the average consumer.

Hello Malpaso,

I think Harry has it correct, in general those comments are correct.

NiCd cells use nasty chemicals, but they are the most robust chemistry when subjected to abuse.

NiMh cells have higher capacity, but are more fragile.

I disagree that digital cameras are not closely related to high torque screwdrivers in power usage. Cameras can tax NiMh cells when all the functions are turned on. Fortunately there are high current capable NiMh cells.

Tom

I use NiMH cells for everything but two-way radios. My wife and I use walkie-talkies very briefly every day. NiMH cells would be dead from self-discharge before the NiCads would be depleted in this particular application.

I have also seen more cells with 'reversed polarity' in these radios with NiMHs than I have with NiCads, which tends to support Silverfox's claim that NiCads will take more abuse. Failing to turn one of these radios off is the only way we've ever hurt any cells.

I've read that there is much less Cadmium in currently produced NiCads than those made in the past, but I dunno.

As long as they're disposed of properly I see advantages to their use for some tasks.