Weird battery behavior

[drummerdimitri]

Hello guys,

I recently purchased a dremel stylus and after having charged the battery to full for a day or so, the tool only lasts about 2 minutes on high. Being curious by nature, i decided to pull it apart and check the voltage on the cells. I was surprised to see two yellow LG 18650 batteries in there, so i removed them and replaced them with 2 2600 mAh AW protected batteries instead and the runtime has now improved to hours lol. As for the LG batteries, I've charged them to a max of 4.14 V and used them in my flashlight and laser. They both started flashing 2 minutes after having been turned on. The voltage dropped to 4 V after 2 minutes of use! Why are these cells behaving in such a manner? Is there anything I can do to revive them?

Thanks!

 

[AUTO XX]

Sounds like the cells are dead, time to dispose of them safely.
I think most fire departments have a battery drop.
They are most likely screwed up enough that they could rupture, try overcharging them (in the dremel) with the tool in your pants, fastest way to get a settlement if they do rupture ^_^.
Pretty cool that they use 18650s though, seems like a waste to use AWs in it, cheap DX batteries would be a good alternative

 

[jeffreythe00]

Glad to hear you got your dremel going good. The battery's you took out are dead. Its typical of lithium battery's to lose their capacity after a few years or if they have been cycled too many times. As these batteries age the don't retain their charge very long and this is why your laser us flashing because voltage dropped below the threshold and it cannot produce the voltage needed. You can make them work again but I forget what the piece of equipment is called. Basically you dump a series of high voltage charges into them but this is dangerous and can cause serious injury. I would reccomend disposing of those cells in a proper mannor. You are better off buying a new set.

 

[LarryDFW]

You can make them work again but I forget what the piece of equipment is called. Basically you dump a series of high voltage charges into them but this is dangerous and can cause serious injury. I would reccomend disposing of those cells in a proper mannor. You are better off buying a new set.

Just to be clear . . ,

Lithium ion cells are NEVER rejuvenated by this method.

LarryDFW

 

[drummerdimitri]

Now the charger doesn't seem to be working! I guess my only option now is to install the dead batteries back in and remove the AW's and exchange it at my local supermarket. What a bummer!