Simple Guidelines on Charging Nickel-based Batteries
Below 70 percent, the charge efficiency of nickel-based batteries is close to 100 percent. The pack remains cool but it begins to warm up towards full-charge.
Nickel-based batteries must cool down on trickle charge when ready, especially NiMH.
Consumer chargers do not always terminate the charge correctly. Remove the batteries when warm to the touch. Discontinue using a charger that cooks the batteries.
Charge at room temperature. Do not charge when hot or at freezing temperatures.
Nickel-based batteries are best fast charged; a lingering slow charge causes memory.
NiMH chargers can charge NiCd, but not the other way. NiCd chargers overcharge NiMH.
Do not leave a nickel-based battery in the charger for more than a few days. If possible, remove the packs and apply a brief charge before use.
Nickel- and lithium-based batteries require different charge algorithms. Unless provisions are made, these two chemistries cannot share the same charger.