How to treat your rechargeable batteries
Recently I've purchased a new battery for my mobile phone. To get the most out of it I wanted to refresh my knowledge, how to treat this new energy pack correctly to keep it alive for as long as possible.
When looking on the internet I was first presented with lots of technical information, how they work et cetera, but nowhere I found immediately how to handle them for maximum lifetime, at least not in easily understandable terms.
So I decided to create a small list of handling tips for the different technologies of accumulators.
NiCd (Nickel-Cadmium), NiMh (Nickel-Metal-Hydrite)
Nickel-based batteries should be "primed" by applying a ~16h charge after purchasing. If not done, it won't cause harm but the full capacity will not be available initially (but increase with usage).
It is not necessary to use up the whole charge before recharging every time, but this should be done every 1 - 3 months to prevent memory effect. For NiMh batteries it is even advisable to not use up all the charge as a depletion wears down the battery faster. It is still necessary to counter the memory effect from time to time. Recharging should happen without interruptions and overcharging (by leaving the the pack in the charger after being fully charged) causes harm to the battery.
When the battery is not used for some time manufacturers suggest a 40% charge for storage altough it is possible to store them full or completely discharged. But more important is to store them in a cool place.
LiIon batteries do not need to be prepared for usage and can be used instantly out-of-the-box.
These type of batteries is quite forgiveable to common usage. Altough it should be avoided to deplete it completely, it may be necessary to perform a full charge-discharge-cycle if charge-indicators get inaccurate readings. When charging, it is under normal conditions not possible to overcharge, so leaving them in the charger is possible. Best performance can be expected, if the charge is kept in the range of 40%-80%.
LiIon should be stored at 40% and under cool conditions. If storing for a long time, recharge to 40% from time to time. If left until uncharged, internal protection circuits may fail and render the battery unusable (or even unsafe).