Should a cordless tool's rechargeable battery be left on the charger when not in use?

[Handplanesandmore]

Some say the battery should be left on the charger even after it's fully charged. I have received conflicting views on this. What do you think or what has been your experience?

Simon

[photobug]

Some say the battery should be left on the charger even after it's fully charged. I have received conflicting views on this. What do you think or what has been your experience?

Simon

I think it will depend on the battery and charger.  My experience from working with high tech batteries and chargers for remote control airplanes or sailboats, where battery chargers can cost 100s of dollars, the chargers have circuitry to detect the rate of charge and will vary the charge depending on the batteries charge rate.  In this case once the battery is charged it will go to a float charging stage, keeping the battery topped off.

Given the preponderance of high tech batteries in tools nowadays I would assume the charger technology has also been upgraded.  I would check with the manufacturer to see check on your particular battery/charger combo.

[TDKPE]

The instruction booklet with my cordless string trimmer specifically recommended leaving it on the charger whenever it isn't used. Battery is 4 years old or so now, and still has the capacity it did when new, as far as I can tell. That's based on doing the circuit around the house, and knowing how low the indicator would go at the end.

[RJT123]

I plug the whole lot of them into one of these and let them have juice for a hour a day, or when needed.
https://www.amazon.com/Intermatic-TN311-...ance+timer

[fredhargis]

I'm guessing some of the variation is due to the act that things have changed (improved) over the years. My first battery drill was a cheapo Craftsman probably 25 years ago. I left the spare in the charger only to find it so hot one day I was lucky it didn't start a fire. The newer ones have overcome all those type problems and probably aren't nearly as dangerous (maybe). Years ago I started using an electronic timer to top off my batteries once a week for about 3 hours, it works so well I still use it even though I probably don't need to.

[Splinter Puller]

Some say the battery should be left on the charger even after it's fully charged. I have received conflicting views on this. What do you think or what has been your experience?

Simon

Lion holds its charge over time much longer then nicad so with the newer tools I do not ever store them in the charger.

[EricU]

when I got some nimh batteries redone by MDO, they came back with a sticker that said to take them off the charger when charging was done (or it would void the warranty?).  I think nimh is harder to charge than Liion, the charger doesn't really know when a nimh is fully charged

Liion and lipoly have a storage charge where they last a lot longer.  That's why you have to charge them when you buy them, they store quite a while at storage charge.  Storage while discharged or fully charged reduces the battery life.  Storage charge for lipoly is 85 percent, not sure about liion.  I have a charger that will only go up to storage charge.  Don't think it works with liion though.

[TDKPE]

Liion and lipoly have a storage charge where they last a lot longer.  That's why you have to charge them when you buy them, they store quite a while at storage charge.  Storage while discharged or fully charged reduces the battery life.  

That's interesting.  I had an Icom hand-held marine VHF radio where the manual recommends storage at about half-charge.

It's sitting on the bottom of Lake Ontario at the moment.  Probably about half charged, so the battery should last a good long time.  

[Willyou]

I have a DeWalt set of 12v drill and impact driver with 3 batteries. Shortly after getting them maybe 4-5 years ago, the manufacturer rep told me it was OK to leave an unused battery on the charger full time. This has worked well for me since then. When one of the batteries on a tool runs low, I just swap it out with the one on the charger. No problem.

[Arlin Eastman]

Most manufactures have it written in there instructions.  I know the ones from Sears say to take them out as soon as charged due to over charging will harm the battery and that is the lithium ion batteries and so far they have done very well over two years and still going strong.