Do your batteries stay charged when left in the charger?

[Willard Foster]

Do your batteries stay charged when left in the charger?

A co-worker has a 14.4v drill that he uses very infrequentley. lets say once a month. He keeps the battery in the charger. When it's time to use it, the battery has no charge. He has changed batteries and chargers and he still has a problem.

Do the chargers shut down after the battery reaches it's charge? Does the charger monitor battery voltage after a charge? It seems I remember that car chargers monitor battery voltage and automatically start recharging.



Thanks in advance,

Bill

[Leo Graywacz]

What brand of tool?

Depends on the charger. Some do, some don't. The earlier vintage the charger the more likely that it will keep it charged, or might overcharge it. The newer chargers, especially Li-Ion have quite a bit of protection circuitry in them. There have been many fires from the earlier chargers that dictated this protection circuitry.

My old DeWalt 12v battery chargers did keep the battery charged while in the charger.

My newer Li-Ion Makita will lose a charge on the charger, but very slowly. But since the batteries charge in 15 minutes it isn't that big a deal.

[Willard Foster]

I thought he has a Dewalt, but I'm not sure.



Bill

[Alan Lightstone]

About once a month (or whenever I remember) I take my batteries out of their chargers and put them right back in. That way, they'll always be charged.

[Jim O'Dell]

The old Ni-cads would develop a memory. If you only used X amount of charge, then recharged the battery, pretty soon, that's all the charge the battery would take. Don't know if that ever changed about the ni-cads, but the NmHi batteries supposedly don't do this. I haven't looked into the Li-Ions. Jim.

[Leo Graywacz]

LI-Ions hav no memory at all. You can charge them anytime you want. Only thing you don't want to do is leave them completely discharged for any length of time. Same as most any other type of battery.

[Van Huskey]

LI-Ions hav no memory at all. You can charge them anytime you want. Only thing you don't want to do is leave them completely discharged for any length of time. Same as most any other type of battery.

I also will not leave Lithium Ion batteries charging unattended or leave them on the charger, in case the charger protection fails...

[Chip Lindley]

Many batteries are drained if left in the charger. The transformer draws current out of the battery. It's best to take a fully-charged battery out of most chargers. Read the instruction manual for exceptions.

[Will Overton]

Read the instruction manual for exceptions.

That's the answer your co-worker needs.


Since this is a buiness, is the power to the charger shut down over night?

[Mitchell Andrus]

I have 3 Makita 12v chargers and there are always a few sitting and waiting. "Smart" chargers started showing up about 10 years ago.... perhaps his is a cheaper .... I dunno, stupid charger?
.

[Paul McGaha]

Maybe I should change my ways.

I have (2) Makita 18 Volt Battery Drills, (2) Chargers, and (4) Batteries. I always keep the batteries either in the drills or in the chargers.

I rely on the chargers to keep them hot and cycle off once they are and to date they have always done so but maybe I'm relying on the chargers too much?

This stuff is all about (5) years old. Not sure what type batteries they are?

PHM

[Don Dorn]

I built the drill/battery shelf system shown on the Woodwhisperer. It seems to work well and the batteries so far have done well.

The chargers are connected to a power strip mounted on the bottom of the shelf system and it's connected to an electronic timer. I set it to run 20 minutes 3 times a week and change the batteries frequently. My thought and hope is that they receive a "top off" but that's about it. It's been about 3 or 4 months and all seem to have a full charge when I use them. I guess more time will tell.

[Will Overton]

Don,

For Ni-Cads that's a bad idea. They will always be topped off, but the run time will be decreased. That's the memory problem you see mentioned.

For lithium that should work, but they don't lose much charge sitting on the shelf anyway.

I'm not sure about the nickle ???

[Steve Leverich]

I've found this to be useful -

http://www.batteryuniversity.com/index.htm

HTH... Steve

[Tom Esh]

Many batteries are drained if left in the charger. The transformer draws current out of the battery. It's best to take a fully-charged battery out of most chargers. Read the instruction manual for exceptions.

Big +1 on that, except I'd say regardless of the instructions, don't leave a bat in the charger when it's unpowered. Rectifiers can / will get leaky with age. Normally it's of no consequence when powered up, but unpowered allows a drain / backfeed.

[Walter Plummer]

Yes...But they seem to wear out faster. We have always kept the Dewalt 14.4 volt batteries in the chargers. The owners manual says it does not hurt them but we have gone through a lot of them and then one caught on fire in the charger.:eek: Lucky it was during the day. Now we have plugged them all into a switched receptacle which we turn on in the morning and off when leaving the shop every evening.

[Rick Christopherson]

The worst thing to do with any battery is leave it in the charger. It doesn't matter if it is an intelligent charger or not. It also doesn't matter what type of battery it is either. As a matter of fact, the lithium ion batteries store best with a partial charge. The longer they remain at full charge, the shorter their life. That includes leaving your laptop plugged in all the time.

When a battery is done charging, take it out of the charger and set it on the shelf. Even the chargers that have a maintenance mode are not intended for the long-term storage like many people use them for.