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Ni-cad Battery repair/regeneration how do I repair/regenerate my dead Ni-cad power tool batteries? Answered

I have several Ryobi 18 volt Ni-cad power tool batteries that over the years have lost all their ability to recharge.  is there a way to fix/disassemble and repair without having to buy all new ones?  I have about 5 or 6 and do not wish to replace everyone of them.


Check out this Instructable: https://www.instructables.com/id/Hot-Rodding-a-Power-Drill-Battery/ I followed some of the guidelines for my drill. I located only one bad cell, bought the replacement locally for $4.50 and soldered it in. The pack works perfectly now (didn't work at all before). By the way, the cells that are most likely in your drill are not "C" batteries, but rather "sub-C." They are a little smaller than regular C batteries. Good luck.

From my experience only 1 or 2 cells in the pack will be dead. You can open the pack and remove the dead cells replacing with a suitably thick wire. 

Although slightly lower in voltage the pack should charge Ok and operate.

Alternatively most cell packs are C sized cells - these are readily available from electrical and electronics suppliers. Build a new pack.

Most power tool suppliers will supply new battery packs AT A PRICE!

Check your yellow pages (do they still have those?) for a battery shop.

Here in the small corner of NE Ohio in which I rest my sorry a...erm...butt, there's a company just South of here that specializes in batteries of all flavors, shapes, and sizes. Most of those units will open pretty easily, and if you're not up to it, I'll bet one of those battery houses will gladly do the install for you at a slight increase in replacement price.

I had success charging up a capacitor to several hundred volts... then flipping a switch to apply the voltage to "zap" the battery.  This clears most internal shorts in NI-CAD batteries... and i got a couple more years out of them.  However, a couple CAUTIONS are worth mentioning. 

   Build a setup that allows charging and zapping without handling the HOT HIGH VOLTAGE WIRES... because you dont want to kill yourself while trying to resurect a three dollar battery !

   The battery MUST be removed from the equipment for zapping. Otherwise, the zapping voltage might damage the equipment powered by the nicads.

I also had success in keeping nicads LONG LIFE by keeping them on charge.  It seems that when you allow the batteries to DISCHARGE by sitting too long and not charged... it causes cells to die much quicker.   I had a job where i worked with HUNDREDS of nicad batteries, and that is what I learned from many years of maintaining lots of ni-cad powered equipment  as a bench technician.

I feel your pain.  The Ryobi 18 volt is my tool of choice.

I had 12 nicad batteries.  About half of them were 4 years old and failing.  So I tried the welder zap routine.  It did not work.  I opened them up and located the bad cells, removed them and found out that by the time I replaced them I could have bought new batteries.  And I'd still have to weld/solder the new cells in.  I'd stlll have packs that were only partially perfect.

So I didn't rebuild any of them and just bought 2 of the new lithium packs.  Now I only use 3 of them and don't need so many packs.

Just my experience.  I'm trying to figure out some project that will use one or more of the empty battery cases.