Rebuilding Cordless Battery Packs

[yhprum]

Anybody rebuild their own?
The individual batteries are available on eBay or Amazon and it looks like a basic rudimentary tab spot welder can be put together without too much trouble. I would buy replacement packs but they are no longer available and my cordless drill works just fine otherwise.

 

[ckeboss]

Yes, easy enough to do.

 

[Mechanical Noise]

I bought some ebay Ni-Cells cells for my Ryobi battery. It's not too difficult to solder the tabs together but I didn't save much over a new battery. I suspect the replacement cells are a little overrated as I think the original cells seemed to have more power when new but the performance of the rebuilt battery is acceptable.

If my batteries become obsolete, I think it will be well worth rebuilding them to keep a good tool working.

 

[Miss the Pontiacs]

I’ve never done it either. I have one power pack putting out only 15v instead of 18v. So I’m guessing one battery has failed or become disconnected. Can you replace a single battery or does it have to be a full reload of fresh cells?

 

[03.]

Have done in the past. I just soft solder a piece of regular wire to them. It is not really worth the effort as far as I am concerned, normally can buy a replacement battery pack for around the same price. If it is an irreplaceable tool then go for it.

Should replace all cells, just one or two is not the way to go.

 

[Bretny]

I have done it with a m18 battery. I replaced the 18650 cells. The battery didn't charge before or after so prob something in the charging system of the battery pack. I harvested the cells for flash lights after that.

 

[Shehzada]

The newer packs have some delicate electronics within. Be careful not to damage it while replacing cells.

Sent from my mobile device

 

[driz]

Anybody rebuild their own?

The individual batteries are available on eBay or Amazon and it looks like a basic rudimentary tab spot welder can be put together without too much trouble. I would buy replacement packs but they are no longer available and my cordless drill works just fine otherwise.

A lot of times I find it’s just not worth it when there’s something better out there that I can catch on sale like around Christmas or the other holiday sales.
On the other hand I’ve had some luck using my Mig Welder to jolt dead batteries Back to life so they’ll take a charge. Sometimes it works sometimes it doesn’t but I don’t for myself that they’re just like new. Since NICAD batteries cost 2/3 the price of lithium ion That beat them in virtually every consideration [emoji1361] when it comes time for more.
When it comes to NICAD I don’t consider them good for anything anymore. After no more than three years you know they’re going downhill. I still have some old black and decker Lithium Ion batteries that we got in 2012. 8 years on they’re a bit weak but still working.
I’ve got a set a Dewalt 18 V NICAD then I got in 2007 and have been looking for an excuse to ditch for a long long time. I noticed in the true value sales circular they’re selling Milwaukee M 18 drill and drill driver set for 200 bucks with a $50 coupon good till the 31st. The Dewalt is going to go on craigslist real soon for a song. That’s that’s gonna be my Christmas present to me.

 

[CJ7VFR]

I’ve never done it either. I have one power pack putting out only 15v instead of 18v. So I’m guessing one battery has failed or become disconnected. Can you replace a single battery or does it have to be a full reload of fresh cells?

It sounds like you have at least two or three cells that are bad. The cells in NiCad battery packs, as well as most other sizes of NiCad batteries are rated at 1.2 Volts. When new, they will charge up to almost 1.4 Volts.

So your 18V battery pack will have 15 1.2V cells in it. And yes, you can just replace the ones that are bad. If you take the battery pack apart you can use a multi-meter to test the voltage of each cell to find the bad ones.

If one of the cells had became disconnected the entire battery pack would not show any voltage since the cells are connected together in a daisy chain. The negative of the first battery is connected to the positive of the second battery and so on. There will be a red lead coming off the first cells positive pole and a black lead coming off the last cells negative pole. When you measure the packs voltage you are measuring the voltage thru all the cells. If you break any connection between any two cells you break the continuity of voltage for the entire pack.

So it sounds like you have just two or three bad cells.

Jim

 

[Arkansas COB]

I have 6 craftsman 19.2v battery packs that I was going to rebuild last spring. I shopped amazon and ebay and all over the net. It was cheaper to just buy replacement battery packs instead of rebuilding the ones i had. Because of the odd number of batteries in the pack you had to by an extra lot just for 2 batteries if I remember correctly.


COB

 

[DenisG]

It's not a good practice to replace just the bad cells in a pack. Look up "battery balancing":
https://en.wikipedia.org/wiki/Battery_balancing

The cells need to work together like a crew sculling a boat.

 

[kbs2244]

I have done it
but I have s local rebuilder that will do it for about 10% over the cost of the cells(after shipping)
so he gets mine

 

[toplessHO]

Ive got a 24v pack for my pullzall puller that needs rebuilt
Replacement is over $140.
looks like I may try it too

 

[Citation]

I have done it with a m18 battery. I replaced the 18650 cells. The battery didn't charge before or after so prob something in the charging system of the battery pack. I harvested the cells for flash lights after that.

Those types of batteries aren't like old Nicad batteries. Depending on the circuits inside they can have software start up procedures or forsake circuits that the system might have blown for safety reasons. Once tripped the only option is replace the fuse.