When it comes to powering up portable devices, there are two common battery choices: Nickel-Metal Hydride, or Nickel Cadmium. They can be used interchangeably due to their 1.2V rating.
These two different battery types are used throughout the industry, so it’s helpful to know what the differences are between them and which type, if any, are more desirable for your application.
The main difference (and the most important) is that NiMH is the newer of the two and is able to provide a much higher energy density than the NiCad battery. In essence, the NiMH battery is twice as powerful and can power a connected appliance for twice as long as the older NiCad battery. All of this comes about without adding any additional weight or size to the battery. Due to this, more industry users are switching to this kind of a battery over the older NiCad. Consumers want a battery that’s able to last longer, all without having to weigh the device down. This is all possible by upgrading to the NiMH style of battery.
Besides just the power of the battery, NiCad batteries are suffering from what’s known as “Memory Effect.” This happens if a battery is continually charged before the power supply is spent. Hence the battery becomes used to not using a specific portion of the power. Once this is the case, the battery no longer uses that area, even though it’s available, which can cause the battery to drain much faster than before. There’s the old theory of not recharging a battery until it is completely dead, and that steams from this sort of a battery. Charging it too soon can eventually reduce the amount of power it provides the device. The NiMH batteries do not suffer from this issue, so it’s possible to connect it to a power outlet or other charging station and not worry about the battery becoming use to the memory effect.
Lastly, NiMH batteries do not contain heavy metals, which are often an environmental problem, so the NiCad batteries are seen more as environmentally unfriendly as well. All of this points to the NiMH batteries as the better option.