Battery charging for cordless power tools - lithium, hydride NiMH, and cadmium NiCad

To get the best use and longest life from your batteries charging, you should store hydrides fully charged and should store cadmiums fully discharged. The properties and recharging of hydrides and cadmiums are different. Hydrides are stored at room temperature.

The lithium batteries are the current technology. The 24-volt lithium battery weighs the same as an 18-volt NiMH battery.

Ridgid offers a lifetime guarantee not only on the Lithium-Ion cordless tools, but also on the batteries.

Quite a few of the new lithium-ion chargers can charge batteries of different voltages, though, so if you don't mind buying different batteries, you can save tool weight by varying the voltage.

Consider starting your cordless collection with a high-voltage-needs tool that eats the most power, like a circular saw. After that, an impact driver has plenty of power. And when you move up in power, like a chain saw, you've got enough of amps.

Batteries of nickel-metal-hydride NiMH are replacing nickel-cadmium NiCad batteries because the hydride cells weigh less and outlast the cadmium cells. More electrical elements can be packed into hydrides, giving them a larger power source. Cadmium is toxin and must be discarded at designated collection centers. Mikita states hydrides allow their drill to run 13% longer, reciprocating saw 23% longer, and circular saw 39% longer than their competitors' cads.

Hydrides can't be used with previous chargers because each type of battery has its own characteristics. The way the temperature rises during charging is different for cad and hydrides. Therefore it is necessary to have a new battery charger that can detect the differences between cad and hydrides.

Hydrides performance is reduced in cold weather because, like all batteries, the chemical reactions inside the battery become weaker at lower temperatures. When using the hydride batteries at temperatures below + 141/4F (-101/4C), it's recommend charging the batteries for 3-8 minutes to provide the catalyst to activate the chemical process and operate at their normal performance levels.

The ventilation holes on the bottom of the hydride packs is due to hydride temperatures tend to rise during charging. To prevent a reduction in battery service life due to the higher temperatures, the holes cool the battery during charging.

Chargers work differently. Smart chargers recharge in an hour or less, rather than 3 hours for others. Some smart chargers provide battery protection by automatically delaying the charge until the battery cools, or you get a lengthy, partial charge.

Panasonic hydrides have a short, 65-minute charging period. The charger is more temperature sensitive helping to reduce damage from a sudden temperature increase. The battery pack features ventilation holes to cool the battery during charging. There is a double capacity CPU allowing both hydrides and cads recharging as they have similar life cycles (+/- 1,200 charge/discharge cycles).

Ridgid's kit can recharge both batteries at once in just half an hour, but you pay for that speed with a relatively short run time.