How should you recharge cordless-tool batteries?
I keep my spare cordless tool batteries in their chargers, and I’ve heard that this practice can damage the batteries. Should I remove them from the chargers as soon as they’re recharged?
—Tom Morgan, Cannon Falls, Minnesota
Go ahead and leave them in their chargers, Tom. Good-quality chargers are designed to keep batteries at a full electrical charge without overheating them. If you charge a battery and then remove it from the charger, it loses up to 20% of its charge the first day, another 10% the second day, and about 1% every day after that.
Follow these recharging guidelines:
• Recharge a battery as soon as you notice a drop in power. Draining the charge completely can damage the battery.
• A battery that’s over 105°F or under 40°F won’t take a full charge, so try to do your recharging at room temperature.