Rebuilding battery packs for tools

I have a couple big cordless tool sets ... drill, spotlight, circ saw in each. These are Ryobi 14.4 volt tools.

Each kit came with a couple battery packs (that you plug into the tool) and I've bought a few more for each. Expensive stuff.
All are dead now.
I've already done the "shocking the dendrites" trick and got a few extra miles out of them. They're all dead for good now.

It's time to replace the cells inside if I'm going to resurrect these tools.

Anyone here ever replace the cells inside one of these battery packs.

And in specific, as I recall there is a contact plate on the top of the cells. I suspect needs to be kindof like tack-welded or spot welded? ... I haven't looked that close in a while.

Any advice or comments would be appreciated.

Nope. Never done anything like this myself, but I watched the engineers at the TV station where I worked replace the cells in some of the battery packs. I assume it's similar. I'm guessing it's similar to a bunch of D-cells strung together or something. Just make sure you get the new ones put back the same way as the old ones, and for heaven's sake, be sure to send the dead batteries in for recycling... those things contain toxic metals!

I rebuilt a battery pack for a laptop based scanner only because they weren't available new anymore. There were jumper plates that had to be desoldered and soldered back on. Wasn't a big deal, but it was only a shrink wrapped pack, not a plastic housing like your batteries would be. If you could get the battery case apart without ruining it, you should be able to get it done. A Batteries Plus store will have the batteries that you need and you might even ask them what they would charge for the repair. Compare that to what a new would cost and see if there is a benefit to doing it.

I've gone through the same thing with several tools.
I was told by a re-built battery place that the Lithium-Ion batteries can't be rebuilt.
I don't know how true this is, but I can't see him lying to me, considering I was trying to buy them from him.

I have rebuilt Ni-cads for Porter Cable drills. Take patience and the ability to solder. The easy way out is check with a Batteries Plus store.

Generally, the Nicad and NiMh batteries take sub-c cells. they are originally ultra-sonic welded to the tabs. if you know what you are dioing, you can solder them. Don't overheat.
Make sure your charger is compatible with the battery chemistry you use.
look at all-battery or batteryspace for cells.

I have no idea what cells are in your power tool packs, but I've created a new pack for some odds and ends things. Generally the cases are sonic welded and you need to cut the case apart and glue back together when you are done. A Dremel works great for taking apart.

The cells are usually spot welded together. You can carefully (quickly without overheating) solder the new cells together using the same layout. Tin each cell by using flux and quickly lay down a bead of solder. As soon as it hardens, touch with a cool, damp rag to cool the solder quickly so it can't soak the cell in it's heat. Then go back and solder the connecting wires to each using the same method.

Shouldn't be too big a deal to do. I'm not sure how much $$ you will save by the time you buy a few quality cells. In my experience you get what you pay for when you buy rechargeable battery cells.

Thanks for all the comments and pointers.

I called the Batteries Plus store and a rebuilding a Ryobi 14.4 battery pak with all new cells is $30.
It would appear that if I do it myself, I can do it for less than half that price ... significant because I have about 9 or 10 dead packs total.

I just found an interesting slide show (unfortunately not a video) on what is inside of an 18v ryobi pack ... my 14.4's look about the same from my recollection (all my dead packs are buried in a box in the garage currently. A good project for the winter.)
Looking at the slide show it's apparent that the trick is to take careful notes of how everything is connected together when the pack case is first opened.
I think this guy may have been just swapping out dead cells ... for the trouble, I would certainly just replace all the cells with new ones like they do at batteries plus.

Here's the slide show ...
http://s357.photobucket.com/user/goodfellow_2004/library/Ryobi_Battery_Pack?sort=3&page=1

I'm going to try and hunt down a video of this process when I get the time ... for now, the pictorial at least gets things started.

Jacob_Marley said:

Looking at the slide show it's apparent that the trick is to take careful notes of how everything is connected together when the pack case is first opened.
I think this guy may have been just swapping out dead cells ... for the trouble, I would certainly just replace all the cells with new ones like they do at batteries plus.

Click to expand...

You do NOT want to mix new and old cells!

gingerdawg said:

You do NOT want to mix new and old cells!

Click to expand...

Duly noted.
Yep, I can't imagine doing that to begin with. Penny-wise and pound foolish ... or not even "penny wise".

Besides, like I say I've already used "higher"-voltage shocks to blow out the (dendrite) shorting in the cells. Thems is all dead.

Looking at that slideshow again, he might have been using the meter just to double-check the new cells before using them; it would appear his final product had all uniformly new cells.