Charging and caring for your tool batteries will give them a long and productive life. Batteries are expensive and should be treated in the same way that you treat expensive tools. Proper battery charging is essential for the life of tool batteries. In addition, performing battery maintenance can be dangerous.

About half the price of cordless drills, reciprocating saws and circular saws is in the batteries. Because replacing these batteries when they fail is expensive so many battery powered tool owners often just get a new tool. Heat is the biggest killer of tool batteries.

Tool batteries heat up as you use the tool. Although that is normal, it the battery overheats you will damage the battery. Do not overheat the battery, back off a bit and your battery as well as the tool will last much longer.

Heat can come from storage of the tool, especially in hot climates. Leaving your cordless tools and batteries baking in your truck box, on the deck in the sun, or on the roof all day will shorten the battery's overall useful life and diminish its ability to take a full charge. This is especially true for high-drain tools like reciprocating saws and rotary hammers. Place them in the shade and keep the tools out of direct sunlight when possible.

In cold temperatures the Ni-MH's chemical reactions stop working at about 14 degrees F; NiCad gums up at minus 22 degrees F. Cold won't damage your battery like excessive heat will but by keeping the battery warm the tool will work better. It takes a battery about an hour to stabilize at the ambient temperature of its environment, so store your batteries inside when you can. If it's just as cold inside, Panasonic recommends leaving Ni-MH batteries in the charger to warm them up for a few minutes for optimum performance. If that isn’t possible warm the batteries inside or in your truck. Put the tool in the truck to loosen up the frozen grease in the gear housings.

As batteries and tools improve do does tool battery chargers. Makita and Panasonic chargers have advanced technology. These smart battery chargers incorporate a light signaling everything such as; battery too hot, charging complete, trickle charging, and a dead battery light. Both companies offer the following tool battery charging tips for optimizing the charge and caring for your charger:

Charge the battery at between 50 and 104 degrees F when possible.
Charge the battery before it is completely discharged. A complete run down can cause cell polarity reversal, which will kill the battery completely.
Never attempt to charge a fully charged battery.
Never use your charger on a generator.
Charging a battery where it's cool decreases charge time. If a charger location is too hot, the charger senses a hot battery and limits or cuts off current.
Battery chargers require little care. Clean out the port where the battery stem fits with compressed air. Always keep your chargers dry.

Do not be concerned with over charging your batteries. Automatic battery chargers sense a full charge and will automatically shut off. However, it is best to remove batteries from the charger after they are charged.

Cordless Drills

Long Life Lithium-Ion Batteries