Bringing Dead Batteries Back to Life

[WildBill]

I have an old Makita cordless drill that uses NiCd battery packs.
I went to use the drill the other day and found one battery was
fully charged and the other was dead. I put the dead battery on the
charger and it showed a short so it wouldn't charge.

I ran across a couple of YouTube videos that showed how to refresh
NiCd batteries. Apparently when they go bad they have some type
of crystal growth in the battery cell that prevents current from flowing.
"Tapping" the battery with a fully charged battery can break down
the crystals and bring the battery back to life. I tried it on my
dead battery and now it will charge. I will run it through some
charge/discharge cycles on my battery charger and measure it's
voltage and capacity.

https://www.youtube.com/watch?v=5B9rx7hoizk

[twomillenium]

Very interesting, I now wish that I had not disposed of those old batteries.

[mojo84]

Wow. I was just about to throw a craftsman drill and battery set away. I'll give this a try first. Thanks

[Wag2323]

I expect it will work for a bit and then have the same problem. Which will give you some time to find a good deal on a replacement.

[2farnorth]

I expect it will work for a bit and then have the same problem. Which will give you some time to find a good deal on a replacement.

^^What he said. I've done with many nicads. It will work some times other times no. Battery life is still short. Just be careful, too much power going to the dead battery can be a bit hazardous.

[NotRPB]

Very interesting, I now wish that I had not disposed of those old batteries.

[Abraham]

Are "lithium" batteries superior to NC or ...?

[Wag2323]

Are "lithium" batteries superior to NC or ...?

Yes in both capacity per area, discharge rate, and voltage. All batteries lose voltage and current as you use them. A cell may be 3.2V to start and drop to 2.7V as it discharges. Your equipment stops working when the voltage is to low. Lithium the voltage curve is kind of a slow decline then fall off a cliff while the NiM type are more rolling down a hill.

[twomillenium]

I went with lithium, they were pricey but worth it.

[oohrah]

NiCd were notorious for going bad if not charged correctly. You had to let them completely discharge, then full recharge. Over time they woud develop gaps or shorts, but could be often recovered as WildBill discovered.

Lithiums are great, because you can recharge them at any time and they have a better life.

[flowrie]

Another option is to have the battery packs rebuilt.
I have an old Bosch drill that I like and it uses nicads packs.
The reason I like it is because it is heavy.
When driving screws the inertia of the heavy drill makes it easier on my hands and wrist when the screws stop.
Find a Batteries + store and they can rebuild the packs for you.

But Li batteries are better and last longer.

[puma guy]

Are "lithium" batteries superior to NC or ...?

Depends on what they're used for. This link is mostly about NiCd and NiMH batteries, but has some info on lithium batteries. Zapping doesn't work on lithiums. There is some useful information on the NiCd "memory" issue

http://www.ka7oei.com/nicds.html

[puma guy]

Are "lithium" batteries superior to NC or ...?

Depends on what they're used for. This link is mostly about NiCd and NiMH batteries, but has some info on lithium batteries. Zapping doesn't work on lithiums. There is some useful information on the NiCd "memory" issue. Look at the discharge chart and temperature index. I keep my spare batteries refrigerated, something I learned a long time ago. .

http://www.ka7oei.com/nicds.html

[ELB]

That's an interesting trick. I would keep a close eye on not only the revived battery, but all batteries while they are being recharged. I've had tool batteries and charges malfunction and begin smoking. Happily I was keeping watch at the time, unplugged it, and got it out of the house. Ditched the charger and the battery when they cooled off. This was with a battery that I had no problem with in the past - I would suspect that revived battery might be even more prone to causing problems.

Don't just plug them in and walk away! especially if they are in your house/garage/tool shed.

[Sport Coach]

I can't stand paying for lithium batteries but they are definitely worth it. Every aspect is superior. I have Craftsman which I thought might be inferior until I bought their lithium then I figure they're similar to all other brands.