If you received cordless, battery-powered tools for Christmas, listen up: Here are some rules for battery use and care – and even if you’ve used such tools for years, you’re probably breaking an important one.

I discovered that I was. And that breaking the rules can cut the life of the battery.

To research for this column, I looked online for advice from battery experts. I discovered the online address for Batteries Plus, a national company with stores in the Charlotte area. It offers replacement batteries for all sorts of devices, including hand tools.

Way up high on its list of tips, Batteries Plus says that we should remove tool batteries from their chargers after they’re fully charged.

As in, don’t just snap the battery into the charger the day after Christmas – and leave it there until you need that new drill sometime in March.

This is the rule I break. Truth is, every tool owner I’ve checked with does the same. But we shouldn’t.

A battery pro at the Batteries Plus reinforced the message. There are different types of batteries, of course, and different chargers. But, broadly, this is a good rule. “Yes, you are hurting the battery if you leave it on the charger (for long periods),” he said.

Long-term overcharging can cause voltage depression, in which peak power drops more quickly than normal.

If yours is a “smart” charger, and the instructions say that you can leave the battery connected, then it’s OK. If you don’t see that spelled out clearly, then remove the battery when it’s fully charged.

I have battery-powered tools from two makers, Skil and Ryobi. The instructions for both say to remove the battery. (Here’s a reminder: Read the instructions with your new tool.)

More tips from the helpful pro at Batteries Plus:

• One measure of a battery’s life span is the number of charging cycles it will take. Manufacturers provide that information.

• Slow, deep charges are better for batteries than quick charges – and remember that even the briefest charge counts as a cycle. “Even if it’s just for five minutes, that’s a cycle.”

• Nickel cadmium batteries can develop battery “memory.” So if you recharge after every brief use, they can learn to lose peak power quickly. Use the battery as long as possible before recharging.

• Lithium ion batteries don’t develop memory effect. They’re smaller and lighter than nickel cadmium batteries, making them popular for tools, and they don’t lose their charge as quickly when not in use. The Batteries Plus expert said that smart chargers are more likely to be provided with lithium ion batteries.

• If we can’t leave our tool batteries on the chargers for months at a time, what’s the best practice? Follow the manufacturer’s instructions. Or, as a general rule, charge the battery, remove it from the charger, and then charge it about once a month when you’re not going to use the tool for long periods.

For more information, check the technical tips on the website of the company that manufactured your tool. Or visit the Tech Center at www.batteriesplus.com.