power tool batteries. charge too long?

[tpolley]

i bought a ridgid 12v cordless screw driver about a year ago. at first i could get a week of daily use. i'd say 50% duty cycle. now i'm lucky to get a few days. i can't imagine the batteries wearing out that soon. the only thing i can think of is i'll leave one battery on the charger while i'm using the other one. so one battery might be on the charger for up to a week. the battery is always warm when i take it off the charger even tho it's been days since the charge cycle completed. the battery charger charges in about 20 minutes then the little green light comes on solid and i assume it stops charging. can it damage a battery over time to let it sit on the charger for extended periods of time?

 

[Theo]

Leaving the batteries on the charger will kill them.

Basically the charger will charge your batteries until they're full then shut down. After some time the battery will loose some of it's charge and the charger will fire back up. This constant cycling is very hard on the batteries.

 

[-B-]

Here are a few tips I picked up along the way. Never put a battery fresh after use in the charger to charge let is come to room temp first. Same thing goes with a freshly charged battery let it cool to room temp before use. As soon as the battery is charged get it off the charger let it cool then top off later.

 

[Danglerb]

Different battery types, brands, types of chargers, there are no rules that apply to all of them, except sooner or later they need replacing. With NiCads when they start holding less and less of a charge, sometimes, running them completely dead before charging will help.

Part of the problem is that most brands WANT to sell you new batteries, so they make chargers that do nothing to extend the life the battery. LiIon require kind of a smarter charger, and since nobody makes stupid chips, the manufacturer is kind of forced to use a decent charging circuit.

 

[64merc]

Leaving the batteries on the charger will kill them.

Basically the charger will charge your batteries until they're full then shut down. After some time the battery will loose some of it's charge and the charger will fire back up. This constant cycling is very hard on the batteries.

+1 on this

 

[lbgradwell]

Leaving the batteries on the charger will kill them.

Hmm. That shouldn't be the case...

With NiCads when they start holding less and less of a charge, sometimes, running them completely dead before charging will help.

Nor this!

Try here for some tips specifically related to DeWalt, but generally applicable...

Batteries and Chargers FAQs

 

[3/8"indestro]

aren't Ridgid batteries guaranteed from Home Depot.

most of the new/latest chargers actually recommend leaving it in the charger as most have the "tune up " feature.

 

[Theo]

Hmm. That shouldn't be the case...



Nor this!

Try here for some tips specifically related to DeWalt, but generally applicable...

Batteries and Chargers FAQs

Unfortunately the info on the DeWalt site isn't generally applicable. The DeWalt chargers are "Smart" in that they know what state the battery is in. Many chargers do not have this feature. Especially older models.

 

[speed bump]

Hmm. That shouldn't be the case...



Nor this!

Try here for some tips specifically related to DeWalt, but generally applicable...

Batteries and Chargers FAQs

Funny Dewalt Chargers kill batteries to. First time I left a Dewalt 18v battery in the charger was the first time I learned about not leaving batteries in the charger.

 

[HolisticPerformance]

what about battery sulfation? Sulfation is a HUGE killer in batteries, especially batteries that do not see day-to-day use. Constant "excitement" of the electrons in a lead acid battery is key to keep sulfur from permantly building up on the lead plates in a battery. I use my drill every day, and I have two batteries. At the end of each day, I swap the drill battery with the battery on the charger, despite how much I've consumed throughout the day. I have no comparison to show that this the best way to maintain a battery, but I do know that sulfation is the major killer in batteries (when dealing with batteries that do not see extremes in weather, like a car battery would).

 

[bchee]

now you guys have me worried about my laptop. I leave it plugged in all the time.

 

[-B-]

now you guys have me worried about my laptop. I leave it plugged in all the time.

Figure the battery has four years after that it is all gold.

If you have a smart battery program use it, at least once a week drain down the battery.