Ask LH: Can I Keep My Cordless Tools Charged Up All The Time?

Dear Lifehacker, Like many other Lifehacker readers, I have the usual collection of cordless power tools that don’t get used quite as often as they should or I’d like. I’ve read that keeping the battery pack constantly charging is no good for the battery. Can you recommend a strategy for ensuring the cordless power tools have the power when you need them but maintaining the battery life? Thanks, Cordless and Powerless

Picture by Douglas Muth

Dear C&P,

There’s no denying the convenience of cordless tools — but there’s also no denying that if you don’t use them regularly, chances are they’ll be entirely out of power when you want to use them. I often find myself thinking “OK, now I need the drill” and then having to hold off while the battery charges up.

If you regularly plan to use your cordless tools, the obvious solution is to leave the batteries plugged into the charger all the time. Assuming you have the space in your garage and shed, this means they’ll always be available for use. But is it a good idea? Many of us vaguely recall the warnings over battery memory that applied to notebooks and mobile phones, and worry that taking this approach will actually reduce the life of the devices.

As we’ve pointed out before in the context of PCs, with modern lithium ion batteries, it’s not true that constantly charging them will reduce battery life. And this is also true for newer power tools, which are designed to charge the battery more intelligently. Here’s what it says in the manual for a Bosch PSR 18 cordless drill which I’m currently testing:

Due to the intelligent charging method, the charging condition of the battery is automatically detected and the battery is charged with the optimum charging current, depending on battery temperature and voltage. This gives longer life to the battery and always leaves it fully charged when kept in the charger for storage.

This won’t necessarily apply if your cordless tools are older, or you have purchased them from a brand-name supplier. But if you have new modern tools, keeping the batteries in their chargers plugged in and ready to go will make it easier to engage in a spot of DIY when the mood takes you.


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