Accidental Battery Charging Overnight

I have occasionally forgotten to unplug my Metabo HPT 36v/18v batteries from their chargers. Would this decrease the lifespan of the battery substantially?

And could anyone give me some best practices on battery charging? I assume the best practice is just to remove it when it’s done charging, but I was curious if there was anything else.

Thank you for the help!

I wouldn’t worry about it. I believe most chargers turn off when the battery is done charging. Some chargers like Ego even discharge the battery a little bit after its been sitting on the charger for weeks, because you aren’t supposed to store the batteries charged.

As for battery longevity, the only tip that really makes a difference is don’t fast charge the batteries unless you really need to.

From what I have heard is if you are storing li-on batteries keeping them at 50% capacity is best. If you are using them more regularly they are much more forgiving than their nicad and nimh predecessors about how you charge them. Like Benjamen said most chargers are smart enough to take care of your batteries. When I was working retail we had mobility scooters with chargers that needed monitoring much to everyone’s chagrin. Thankfully the average power tool charger is much better than that.

Good to know. thank you all!

This is probably not best practice, but I set up a “charging station” in my workshop and in my office for my 20VMax, Flexvolt, and M12 batteries. It’s just a shelf. I put discharged or partially charged batts on the left. The charger is in the middle. Charged batteries on the right. When I need a battery I grab one from the right-hand side. When I’m done using a battery I put on the left side. Whenever I happen to be walking by the charger and I see that it’s finished charging, I take the charged batt and put it on the right-hand charged side. If there’s any discharged batts on the left then they go on the charger. This means I end up keeping some batts fully charged, and often times batteries get left on the charger overnight if not for days. I have not had any issues with any of my batteries failing prematurely. I’m still using some of my Dewalt 20V 5ah packs from 2013 and they have all been handled this way, the only batteries I’ve had to replace have been from physical damage (cracked housing).

I have a family member who does a lot of gardening and uses the Ryobi 18v system. They keep their charger in the garden shed which has no insulation, AC or heat, and it gets mighty hot in there during the Texas summer. They keep one battery in the charger and the other, charged, sitting right next to it. They’ve been using those same batteries for 5 years now and they’re still working fine.

In my experience modern power tool batteries are remarkably tolerant of abuse and I wouldn’t overthink things. We’ve come a long way since the Ni-Cd days, benjamenjohnson is correct that modern chargers auto-shut-off when the batteries are charged.

like said above a lot of the newer tool battery chargers are smart enough to stop and then monitor the battery - but not many indicate they are doing this.

Wow, looks like they are pretty resilient. I just got spooked by all the user manuals. :sweat_smile: