# Battery Chargers on Timer - Good Idea?



## Zuki (Mar 28, 2007)

I have been doing some reading on electrical usage and came across vampire electricity usage . . . when seemingly innocent items plugged in will use a significant amount of energy ($$$$$$) over time.

I got to thinking about my battery chargers. they are always plugged in with a battery in them. Would it cause damage to the battery if I put the charger on a timer only allowing it to charge for 3 hours per day?

So it will always be plugged in, but only charging for a portion of the day . . . thereby saving $$$$$.

Thoughts?


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## EEngineer (Jul 4, 2008)

It is a very good idea… particularly on cheaper chargers like those typically used for power tools. Constantly charging the battery will decrease the lifetime. Where I work they used battery powered screwdrivers for a lot of electronic assembly. Battery replacement went way down when they simply made sure that the battery chargers were unplugged every night rather than continuously charging them throughout the night.

The more sophisticated batteries for electronic equipment have limiters built into the batteries or chargers to limit the charging current as the battery approaches full charge. This prolongs the battery life. However, there is still power used in the rectification and charging circuitry itself, which is wasted power.


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## hairy (Sep 23, 2008)

I'm a big fan of a trickle charger. What they do is maintain a full charge, and do not overcharge a battery.

This one is on my motorcycle: http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=69981&group_ID=17835&store=snapon-store&dir=catalog

This one is on my standby generator. http://matcotools.com/Catalog/toolcatalog.jsp?cattype=T&cat=2500&page=1&#58391 Part # MC15

Most tool companies have one. Look for a "smart charger".Both of these are good quality. in my situation it is cheaper than a new battery.

I'm not sure what you are trying to keep up, but I had one for several years on an antique truck that was driven infrequently. Small batteries, such as lawnmower, motorcycle etc. will quickly be ruined if left in a low charge state. The lead plates get clogged,sulfated, and then the battery won't take a charge. Gel batteries eliminate this problem.


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## Zuki (Mar 28, 2007)

Sorry . . . I have a Dewalt 18v and two 12v drills.


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## hairy (Sep 23, 2008)

Wow! Where was I coming from? Maybe I answered a question you haven't asked yet?


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## Padre (Nov 5, 2008)

Most modern day chargers are designed to go down to 'trickle' mode when the battery is full. Having said that, I think that 90% of them don't work.

So I think it is an excellent idea to put your chargers on a timer.


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## EEngineer (Jul 4, 2008)

Yeah, lead-acid batteries do require a trickle charge for exactly the reason you mentioned: plate sulfation. However, gel-cells do not eliminate the problem. They are slower, but the plates do sulfate. What you pay for trickle charging is probably a lot less than a new battery.

NiCad batteries, common in rechargeable power tools up until just recently, do not require a trickle-charge to keep them functional. Continuously charging them can lead to a runaway effect that actually decreases the lifetime or even destroys them. As someone else mentioned, you can get so-called "smart" chargers that reduce the charging current on a fully-charged battery, but the ones you get with the tool itself are almost always "dumb". I have 2 cordless screwdrivers in my garage that are on a timer - about 3 hours on out of 24. I find that's enough to combat the self-discharge rate and they have lasted about 2 yrs now. I never got more than 6 mos out of batteries I charged continuously.

Lithium ion batteries, found in most electronics and becoming popular in power tools now, are a whole 'nother story. For many reasons, related to catastrophic failures that result in fire or outright explosion not just a dead battery, most li-ion batteries include smart charging electronics right in the battery itself.


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## FatherHooligan (Mar 27, 2008)

A friend of mine used to do a lot of fire calls and she mentioned that a surprisingly large part of the fires she attended were probably caused by the battery chargers being left plugged in which then overheated, burned and caused a fire…ever since I have been unplugging my chargers and all those transformers that seem to breed like rats when you have electronic equipment around.


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## tblank (Apr 8, 2010)

Instead of a timer, what about wiring a switch to the charger's outlets and you just flip the switch when you come in or leave. Put it next to the light switches.


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## rcp612 (Oct 15, 2009)

Marc Spagnuolo has a video showing a simple charger/driver shelf using a DowelMax for assembly. At the end of the video he mounts it on a wall, positions his drill-drivers on top with the battery chargers beneath, and plugs all the chargers into a timer. If it's good for him,,,,,,,I'm just saying….............


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## Zuki (Mar 28, 2007)

Since my initial posting I picked up a couple of digital timers. I set it up to charge for 4 hours per day. It seem to be working fine. Yesterday evening I popped in a dead 18v and this evening it was fully charged.


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## GKS (Apr 23, 2019)

Hey friends , can anyone can suggest to enable the 26V lithium iron battery chargers needs to add the timer .. when the battery inserted to the battery charger needs to 'ON' supply the power to the battery & battery needs to lock until get full charge .


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## ibewjon (Oct 2, 2010)

I have had my charger receptacles wired to timers for years. I have a timer with different fixed times, press 60 and get a 60 min charge. I also have receptacles on an adjustable timer for on once a week for maintenance charging. I used permanent inwall timers wired direct to receptacles, less cord to deal with.


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## bilyo (May 20, 2015)

I don't mean to suggest that the timer is not a good idea. But before you go to the time and expense (small, I know) you might want to do a little more checking on the need for it. My experience is with a Dewalt set of 12v drill and impact driver that came with a third battery. I've had this set for more than 5 years and have always kept one battery on the charger. I checked with Dewalt and they said it is OK to do so. I'm still working with the original batteries and have had no problems. Of course, it is using a small amount of power all of the time. But, there doesn't seem to be any adverse effects on the batteries.


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## PCDub (Sep 24, 2017)

((Regarding the concern for "vampire" electrical usage, note that using a timer will also use electric!))


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## ibewjon (Oct 2, 2010)

I am not concerned with small power usage, as the motors in the shop consume more power starting than the timers or chargers could ever use. I just want the chargers off because I am not in the shop every day, maybe not for a week at a time. All of my tool receptacles run through a contractor, so the power is off to that panel when I leave. Only lights, heat, and a few receptacles remain powered when I leave. Safety first.


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