Batteries & battery chargers

[Bruce Page]

I have two DeWalt batteries/chargers that I leave plugged in to a power strip 24/7. Is that a good thing to do?
What do you all do?

[Chris Padilla]

My Festool stuff is plugged in 24/7....

[glenn bradley]

Read the manual. Most newer systems stay plugged in and charging all the time. I have an older Makita (11 years or so) that instructs you to remove the battery after 90 minutes and not to leave it in the charger. I assume the older chargers and batteries ain't so smart as the new ones.

[Bruce Page]

Read the manual?!?:confused:

[Karl Brogger]

I leave all my chargers plugged in all the time. One I bet hasn't been unplugger for 4-5 years. I don't like to leave the batteries in, but I have no reason not to. Just one of those obsessive compulsive things.

[Matt Meiser]

I got something from Battery Rebuilders when I had some rebuilt saying that you shouldn't. More importantly, a guy who used to be a member of my club had a major house fire that the fire investigators traced back to a battery charger in his shop. IIRC, it was the same color as yours ;)

I plugged all my chargers into a power strip. I just kill the power to it after the batteries are done charging. I'm not perfect about remembering, but they spend a lot less time plugged in than they used to. I'd really like some kind of timer but they are pretty expensive from what I found due to the need for about a 2 hour timer. I usually pull the batteries from the chargers too, in case they put some kind of drain on the batteries while unplugged?

[David Christopher]

If the batteries are not in the charger the circuit is not completed and it will not draw power and will not hurt the charger

[Tom Esh]

Glenn's right. Check the manual. Not all charging systems are created equal. (I trashed quite a few old nicads before I learned that.) Generally the newer tools have smarter charging / monitoring systems and it's practically a necessity for L-Ion.

[glenn bradley]

Read the manual?!?:confused:

That did sound kinda blunt didn't it :D. I was trying to say that some makers are different than others. My Makita doc says to pull the battery after charging but my DeWalt (almost as old) doc says something like "the charger is the best place to store your battery", as in "let that thing cook all day long". :D:D:D

[Chip Lindley]

But But!!...that lil green light is still *ON* !!!......

[Chip Lindley]

......... I assume the older chargers and batteries ain't so smart as the new ones.

Well... the WORLD has Dumbed Down a lot in 11 years, but electronic circuits are smarter than ever! Most *BEEP* when your battery is *Dun*...if there is anyone around to hear it.....which reminds me.....

If a tree falls in the woods, and nobody is around to hear it?.....Is the Husband still Wrong?????......hmm...

HoHoHo~! MerryChristmas Creekers!!

[Kelly C. Hanna]

One of my guys used to have his own battery company. He told me to NEVER leave the charger plugged in with a battery in it. The battery can actually lose a charge over time and the charger can short out and cause a fire. Chances are slim he said but with my luck I decided not to push it.

He told me that it's best to charge the battery and then remove it shortly after full charge is reached, then keep the battery in a warm place until needed.

[Tom Veatch]

I don't believe the OP was saying that there were batteries in the chargers, just that the chargers were plugged in.

As mentioned, some of the later model "smart" chargers are perfectly OK to be used as a storage location for the batteries. They have internal circuitry that monitors the charge state of the battery to avoid overcharging. But if the charger is not so equipped, you can very easily ruin a battery leaving it on the charger past the point of full charge.

And as also mentioned, if there is no battery in the charger, the current draw of the charger is very low or non-existant, depending on the design of the particular charger.

That being said, I have a couple of Dewalt chargers that are plugged in 24/7.

There have been at least three recalls on Dewalt chargers:

http://www.cpsc.gov/cpscpub/prerel/prhtml96/96176.html
http://www.cpsc.gov/cpscpub/prerel/prhtml01/01057.html
http://www.consumeraffairs.com/recalls/dewalt_02.html

You should check to be sure your's aren't covered by that recall.

[Kelly C. Hanna]

Yeah I know, I was just covering all the bases. he told me not to leave ANY charger plugged in. Not only is it a waste of electricity, but it can be a fire hazard and I know of no charger that is smart enough to turn itself completely off when there's not battery in the slot.

As to the battery being left in the charger while plugged in, which ones have you read about that say it's OK? And I wasn't talking about overcharging...I said they can actually lose the charge over time even when plugged in.

[Dewey Torres]

Oh well, forget the charger Bruce ...nice new avatar!

[Tom Veatch]

As to the battery being left in the charger while plugged in, which ones have you read about that say it's OK?

Some references:


The smart chips allow you to safely fast charge your batteries without worrying about overcharging them. Smart chargers will charge your batteries more consistently because they can sense when your batteries have reached a full charge by measuring the voltage rise and change. They will then switch to a trickle charge which will keep the batteries fully charged until use.http://www.starbatteries.com/chargerfaqs1.html#Should (http://www.starbatteries.com/chargerfaqs1.html#Should)

(Note: other sources offer suggestions that batteries not be left on trickle charge beyond times that vary with the source from a few days to a year.)

See Item #3
http://support.dewalt.com/cgi-bin/dewalt.cfg/php/enduser/fattach_get.php?p_sid=6FEB43mj&p_li=&p_accessibility=0&p_redirect=&p_tbl=9&p_id=685&p_created=1100020449&p_olh=0

Google "Smart Charger" for more.

[Kelly C. Hanna]

I see...never used a charger other than factory for any of my tools, so I have to say I know nothing about that. My last experience with DW batteries wasn't as stated in their FAQ on that page. I had two different sets that went bad before the warranty period ended because of them being left in the charger. I must add that I no longer own any DW cordless tools. Once the batteries were replaced I sold the tools and bought Makitas. I now have the Lion set and there's no memory whatsoever. I still never leave them in the charger. had tghe batteries now for over two years with no issues.

[Bruce Page]

Oh well, forget the charger Bruce ...nice new avatar!

Thanks, I cropped that out of a group shot from Kodiak a couple of years ago. Notice the ear muffs… it was ~10 degrees! :eek:

[Lee Schierer]

I'd really like some kind of timer but they are pretty expensive from what I found due to the need for about a 2 hour timer.

Wire an outlet into one of these.http://www.1000bulbs.com/images/ELEC-ET724ACS-200x.jpg

Electronic timer (http://www.1000bulbs.com/Lighting_Controls/Auto_ShutOff_Timer/In_Wall_Electronic_Timers/38469/?&utm_source=Froogle&utm_medium=shopping+site&utm_campaign=Froogle+datafeed)
You can pick them up at the Blue Box store for about $25 and can program them to stay on for any length of time you want on any day you want. They work great for turning on the outdoor lights too!

[Chris Padilla]

Oooooo, very nice, Lee! Looks like I'll be asking Santa for one of these! :)

[Jerome Hanby]

I grabbed a double metal ac wall box, a double cover with an AC outlet and wall switch opening, a 12 hour mechanical movement electric timer, and a power squid. Wired appropriately and plugged in all my chargers. Now I can load them up, set the timer for 8 -12 hours and it turns itself off. If I'm not actively using the batteries (on, this is theoretical, since it hasn't happened yet) I can switch it on for an hour every few weeks to make sure they all stay hot. Some of the batteries get 10 hour sessions they really didn't need, but I figure it beats leaving them plugged in 24/7.

[Kevin Lucas]

I have a 14.4 battery pack and got a new charger that will charge any voltage for that type. just glanced at the destructions but it works great. and the husbands always wrong especially if hes right. It says so in that invisible wife's handbook I can never find!

[Steve Clardy]

I have 4 chargers all on one power strip.

I try to turn the power strip off every evening. :rolleyes:

[Matt Meiser]

Lee, I'll have to take another look at the blue box--I looked a few years agao and didn't see that.

[Peter Gregory]

My Dewalt charger, which is 10 or so years old, draws power while plugged in and empty, and my Panasonic charger doesn't. I figure the less energy I use the better, so pull the plug on my empty chargers.

Now that I have read this thread, I might need a power strip to switch off instead. That is a better idea. Think I have a power strip in a box, around her somewhere.

[Curt Doles]

It's difficult to keep up with all the battery and charger technology. A smart charger would sense the level of charge, like an automotive trickle charger and give it a boost as needed to keep fully charged.

I know I've owned chargers that just put DC to the battery regardless of condition, and they ran hot. Leaving those batteries charging would definitely shorten their life. Also, the discharge rate. off the charger is about 30% per month for NiMH and 20% for NiCd. So if the battery was off the charger for a month, and it's an aging battery, you may not get much out of it.


Many household devices consume power when off, similar to a charger, many devices have been responsible for fires. A lot of laptop batteries were recently recalled because a few burst into flames. I don't think a charger with no battery in it would be a big concern, unless there was a recall or history of problems.

I'm betting many people are going to be disappointed when they don't get the longevity out NiMH batteries. I've already had two laptop batteries expire at about thirteen months.

Maybe they had dumb chargers?

But, I believe the best advice was given earlier, follow the manuals instructions.

Curt