Cordless Charger Timer

[glenn bradley]

I had used a 24 hour timer for while; the kind that turn lights on and off to make it look like you're home. Problem was I would wander off or get distracted and let the thing turn on and off for a couple days.

I found a niche over the washing machine and put up a little shelf. I split the duplex outlet and added a wind-down timer for the top outlet. Now I can pop the batteries in and twist the dial a bit and not worry about wandering off.

[Dan Friedrichs]

If your chargers don't automatically stop when the battery is charged, that's a good idea - it will definitely extend their life.

[glenn bradley]

I run a Makita and a couple DeWalts that are about 10 years old. One battery rebuild on each. Chargers are wayyy pre-smart but the drill-motors just keep going ;-)

[Jeffrey Makiel]

I was considering doing the same thing for my three DeWalt chargers. I don't like the idea that they are always plugged in for safety reasons.

Good post!

-Jeff

[Rick Christopherson]

Shutting down a charger (even the intelligent chargers) after a few hours is a good idea. However, there are a lot of woodworkers that keep topping off their fully-charged batteries every week or month with some sort of timer system. This is bad, and will degrade the battery rapidly.

Regardless whether it is NiCd, NiMH, or LiIon, the longer the battery sits at 100% charge, the shorter its life will be, especially if the charger is continually adding a trickle charge. Let them discharge a bit before topping them off.

Yes, this one-time timer is fine, but if you (or anyone else reading this) is using some sort of weekly or monthly timer to top off the battery, or heaven forbid, just leaving the battery in an active charger, you are killing your batteries.

Over charging batteries is the most common reason why they die prematurely.

[Robert Reece]

Hi Rick-

I have a Makita impact driver with two batteries. When one starts to go down, I swap it with the one in the charger. The charger is always plugged in.

So how do you manage your batteries such that they are ready when you have a busy week or two away from the shop and then Saturday morning at 10AM comes and you need to start doing some work? Or worse yet, sometimes I don't have such a busy week so I end up doing a few things during the week. It just seems simplest to leave the batteries in the charger and assume the manufacturer and the charger are smart enough to manage them well enough.

FWIW, I've had my Makita for several years and my batteries are just showing signs of not holding charge like they used to.

[Rick Christopherson]

Your batteries won't self-discharge a significant amount in 2 weeks sitting idle (unless of course they are already degraded). When your battery is charged, simply remove it from the charger until you are ready to use it. No one has a gun to your head to force you to maintain your tools, so how ever you want to proceed is entirely up to you. You obviously don't buy what I have to say, but I also don't get paid to convince you either. The choice is entirely yours.

[Thomas Syrotchen]

Rick,
I had always believed the same thing until about a year ago, when someone pointed out some literature from Dewalt (I use their 18V batteries). At least in the case of Dewalt, they state that it is better to leave the battery on the charger in maintenance mode as opposed to removing them from the charger. They actually state that a battery will loose up to 20% of its charge in the first 24 hours off the charger, 7-10% the following day and about 1% every day after that. I was able to find that document in the FAQ's of the support section on their website. Might be worth it to make a quick trip to the manufacturers website to see what they recommend. Dewalt also offers an explanation on why power tools are different from the old cordless phones that without a doubt developed a memory if you continually charged it. http://support.dewalt.com/cgi-bin/de...i=&p_topview=1

[glenn bradley]

Robert: I sometimes don't use a cordless for a week or two during phases of different projects. The batteries hold their charge. I do store them with the caps on and in a wooden drawer.

Thomas, both tools are quite old and the manuals state not to leave them in the charger. It helps that I have several batteries so there is always one that is up to the task if not three ;-)

Another benefit from the older tools is I have found batteries and chargers for pennies on the dollar at BORG clearance tables and such. $10 for two DeWalt batts and a charger a couple years back added to my rebuilts ;-)

[Wes Bischel]

Glenn,
I did the same thing - same kind of timer. So far It has worked out. If I haven't used it in a while, and know I'll be using the drill hard, I'll pop one battery in the charger just to top it off.

Wes

[Robert Reece]

Your batteries won't self-discharge a significant amount in 2 weeks sitting idle (unless of course they are already degraded). When your battery is charged, simply remove it from the charger until you are ready to use it. No one has a gun to your head to force you to maintain your tools, so how ever you want to proceed is entirely up to you. You obviously don't buy what I have to say, but I also don't get paid to convince you either. The choice is entirely yours.

Rick-

I don't believe or disbelieve you. I just want to understand how you manage your batteries. I'd love to maximize my battery life, but not if I have to pick my nose for an hour on Saturday waiting for a battery to charge up. I believe my Makita manual says leave it in the charger. Of course Makita is also in the business of selling new batteries.

Rob

[Chris Padilla]

I leave my Festool batteries in the chargers continuously charging so that I always have a fresh battery. I've been doing this since day 1, 5 years ago. The key is the battery charger, I think. One set of batteries for my TDK-15 drill finally died and I've had both rebuilt but the other set for the CDD-12 drill is still going and it older than the TDK by at least 1 year...maybe 2!

[Jerome Hanby]

I did the same thing. Built the whole thing into a double outlet metal box, with an outlet and the timer side by side. Plugged a power squid into one of the outlets to accommodate all the ac adapters.

[Chip Lindley]

Back to the original poster Glenn's solution to stopping continual battery charging...

Some chargers will deplete a battery if left in the cradle, turned off! A rude awakening if you expect a fully charged battery and it is completely dead. IF...this is not the case, Glenn's is a viable solution. IF this IS the case, a good reason corded power tools are still very usable!

Another thought: Manufacturers have a vested interest in selling *extra* (read: replacement) batteries at exhorbant prices. Who knows if the whole truth is being told when a manufacturer recommends keeping the battery on *trickle*? Harmless Convenience? or Ploy?

[Mark Grotenhuis]

My Makita 18V batteries will drain while on the charger if I unplug it. I've done it couple times by accident. I unplugged the charger with the battery still on it, threw it in my truck, and the next day that battery is completely dead. I would think the same would happen if you put a timer on it. Hopefully not all battery chargers do this ... but I know the newer style lithium-ion Makita's do. I have 3 chargers and 6 batteries, all 3 chargers do it. One charger was bought 2 years ago, another a year ago, and the last 6 months ago. So obviously they don't see it as a problem worth fixing. It's a little annoying, but not a big deal.