One of the most commonly asked questions about rechargeable batteries is whether or not it is true that rechargeable batteries will develop a “memory.” There really is no simple answer to this question. It really depends on what type of rechargeable battery you have. Li-ion (lithium ion) batteries are not prone to memory problems.

The issue of rechargeable batteries developing a “memory” is most typically a problem with NiCd (nickel cadmium) batteries. If you only use a little bit of the battery’s energy each time you use it, and then charge it up, the battery will tend to develop a “memory” after a few dozen of these short cycles, and will not be able to store as much energy as when they were new. For this reason, you should always fully discharge a NiCd battery before you recharge it. This will greatly extend the life of your batteries. More NiCd batteries are replaced for this reason than for any other reason. NiMH (nickel metal hydride) batteries can also have a memory problem, but it is not nearly as severe as with NiCd batteries. Improved chemistry has greatly improved this problem however.

Regardless, when you receive a new NiCd or NiMH battery, you should ‘season’ it properly before using it. Charge the battery fully, and then discharge it completely several times before you use it. This will help ensure that your new battery will be capable of holding a full charge when you use it. Some devices will also drain batteries slowly, even when they are turned off. When you are storing your device, it is good practice to always remove your battery before storing.