What's the best way to keep batteries charged?

Q:

Our sons have given me a number of cordless tools, but when I want to use one of them, the batteries soon run low because they’ve lost their charge sitting on a shelf. Is there a way I could plug the chargers into a power strip, and then plug the strip into a timer to charge the batteries, say for 30 minutes every day? Or would that harm the batteries?
—Robert Jesse, Moweaqua, Illinois

A:

That approach is a crude version of what some tool battery chargers do automatically, Robert, and it could work if left on long enough each day to fully recharge the battery. Leaving a battery in an unplugged charger shouldn’t create problems for either the battery or charger.

However, a check of your tool owner’s manual may make all of this unnecessary. More-expensive cordless tools usually come with high-end features, such as chargers, like the one shown above, that bring a battery up to full charge and feed it a maintenance, or “trickle,” charge as needed. 

Other tool manufacturers discourage leaving batteries in unattended chargers for long periods. A charger malfunction could result in the battery going into continuous overcharge and becoming overheated. Only the owner’s manual for your tools can specify whether continuous charging is right for you.

Read more about

Tip of the Day

Cutting corners pays off for panels

100505806

After a raised-panel split in a cabinet door, I performed an autopsy to see what caused the... read more