Nickel-metal hydrate batteries

[Gene Michael]

The ni-cads for my cordless drill are about shot, so ordered a nickel-metal hydrate as a replacement. According to what I've read, they don't form crystals the way ni-cads do and last longer. Some of the tech sites say that they don't last as long if they have to perform under load, but I'm not sure how to interpret this (how much load is too much?). Some sites also say to store it at 40% power. Not sure how this would be determined Does anyone have experience with this type of battery, and if so, can you shed some light on the above comments? Thanks in advance for any info you can offer.:D

[Chris Friesen]

I think it's actually nickel metal hydride, or NiMH. The most important thing is whether your charger can handle the new battery pack. Depending on the type of charger it could overcharge, undercharge, or properly charge the new pack.

On the plus side, NiMH doesn't have memory problems and has a higher capacity (for the same size/weight) than NiCad.

On the negative, it self-discharges about twice as fast, doesn't do as well below freezing, can't handle as many recharge cycles, and doesn't do as well under very high-rate discharge (ie, drain the battery in 20 minutes kind of thing).

[Jason Abel]

All this information is very specific to the different types of NiMH batteries. NiMH AA and other standard batteries are very much so like was described by Chris. Some Sub-C (Batteries used in tool packs) are like was described but not all of them are. It all depends on internal resistance, number of windings, and electrolyte used. The NiMH's we use will put out higher amperages than any other NiCad Sub-C on the market. It will also last longer sitting on the shelf when not in use. They also cost you your first born but unfortunately quality NiMH Sub-C's do not come cheap. Hope this helps and PM me if I can be of any further assistance.

Regards,
Jason
MTO Battery