Approx Charge Time = Battery mAh rating / Charger Output mAh rating
Example: 2.7A Charger Output for a 2100mAh battery = 2100/2700=.77hr=46min
Please keep in mind we did not figure in any charge that may be left in the battery and/or loss due to resistance but this formula will get you close.

NiCad (Nickel Cadmium)
NiCad batteries like to be fast charged and then removed from the charger. Please be sure to check the charge rate of your charger and make sure the battery can safely handle that charge rate. Our charge rates can be found with our rebuild services and also on the individual cells page. Many battery chargers DO NOT completely shut off after the one hour quick charge. This makes it necessary for you to remove your batteries after the batteries finish charging. If you leave the batteries on the charger too long too often premature failure will occur. It is important to keep a close eye on your batteries when charging, especially if you do not have a thermistor or thermostat in your battery to tell the charger to stop charging when it gets too hot. These sensors typically hook up to an external contact on your battery and it marked with S or T. Batteries should be recharged when you notice a drastic loss in power/performance. Over discharging a NiCad battery can cause fire and permenant battery damage.

NiMH (Nickel Metal Hydride
NiMH batteries also like a steady charge just like the NiCad batteries. The NiMH batteries we use can be safely used in a NiCad charger without problem. Many battery chargers DO NOT completely shut off after the one hour quick charge. This makes it necessary for you to remove your batteries after the batteries finish charging. If you leave the batteries on the charger too long too often premature failure will occur. Typical NiMH battery packs will have both a thermostat and a thermistor to accurately monitor and control charge rate but in most cases this still does not fully isolate the battery from the charger. The biggest difference from NiCad to NiMH is the capacity. A NiMH will typically hold a lot more mAh and therefore run longer on each charge.

LiIon (Lithium Ion)
Lightweight battery that CANNOT be charged on a NiCad or NiMH charger. Doing so WILL CAUSE FIRE and/or EXPLOSION. Lithium Ion batteries require a LiIon charger and a regulator board which keeps the cell voltage from dropping too low during use or going to high during charging. Without this regulator board the use of LiIon batteries is extremely dangerous. It is recommended to charge LiIon batteries in a fire proof area that can accept a fire should one occur.