Rebuilding 18 volt batteries for cordless tools.

[Dave Shepard]

Has anyone done this? I lost one of my Milwaukee batts this summer, and I was going to retool with Makita, as they seemed to be the popular choice at work. My boss gave me his old Milwaukee tools, with a bunch of dead batteries, so I bought a couple of new ones and now seem to be committed to Milwaukee tools. The more people I talk to, the more support I get for Milwaukee, although I think Makita would be fine, too. I now have a bunch of batteries that won't take a charge, and I was thinking of rebuilding them.

[Magicman]

I have bought new batteries and rebuilt a few, but finding high ah replacements is a chore plus expensive.  After you add shipping to that, I felt that I was better off buying a warranted replacement.

[clearcut]

Last time I went to try this I found pre-built after market batteries on eBay were about the same cost as buying the cells. That was for a Dewault.

[Dave Shepard]

There used to be a business near me that rebuilt batteries, but I think they moved. The 3ah batts from Home Depot are $140/pair, and the new 5.0 are $129 each. I'd like to know why the Festool 5.2 are only $45 each. I guess if I can get a couple of years out of a pair that may just be a cost of having the convenience.

[snowstorm]

i bought the big mikta set 8 yrs ago 18v most of the tools were pretty good. the drill has been fixed several times. new gear box new  chuck gets hot but it still works. the flash light needed a new circuit board. the plastic ring that holds the lenses and bulb in. if you get it tight enough to hold the bulb in it breaks. batteries might last a yr at best.  i have some 12v Milwaukee. the greese gun is over 3yrs old still running on the battery that came with it 

[Kbeitz]

Been there done that...
Some things I learned.
Most all take the same cells inside.
So what I do is search E-bay for cheap battery's of any make.
Then I take them apart for the cells and put them in my battery case.
You can reprieve old battery's by hooking a high amp battery charger to you old dead battery's.
I only do this for a few sec. Be very careful. I was told they can come apart doing this.
It has never happen to me and I've done a lot of them.
They will then again take a charge.
The newest battery's have electronics inside. I have not messed with them.

[JB Griffin]

I'd like to know why the Festool 5.2 are only $45 each.

I guess they feel sorry for the people that spend $300-$600 on a bare tool.
Supposed to be the best there is though.

[jcbrotz]

I'd like to know why the Festool 5.2 are only $45 each.

I guess they feel sorry for the people that spend $300-$600 on a bare tool.
Supposed to be the best there is though.

They make their money on the tool not the batteries if I had the money all my tools would be festool no comparison to quality. That said I own lots of dewalt and they don't want to support 18v anymore but are finally making a 20v-18v adapter.

To answer the question they are tough to get right with most better know how to soider sending them in to be rebuilt is also an option dewalt isn't to bad with that.;

[Dave Shepard]

I have four of the small batteries that won't charge. I might look into sending them out if it's not too expensive. After looking around, I might just buy a new tool with the big batteries, some kits are not much more than two 5.0 batteries outright.

[Peter Drouin]

Been there done that...
Some things I learned.
Most all take the same cells inside.
So what I do is search E-bay for cheap battery's of any make.
Then I take them apart for the cells and put them in my battery case.
You can reprieve old battery's by hooking a high amp battery charger to you old dead battery's.
I only do this for a few sec. Be very careful. I was told they can come apart doing this.
It has never happen to me and I've done a lot of them.
They will then again take a charge.
The newest battery's have electronics inside. I have not messed with them.

I have some I'm going to try that on. Just have to see which one is + and-- on the batt.
Thanks.

[Kbeitz]

Been there done that...
Some things I learned.
Most all take the same cells inside.
So what I do is search E-bay for cheap battery's of any make.
Then I take them apart for the cells and put them in my battery case.
You can reprieve old battery's by hooking a high amp battery charger to you old dead battery's.
I only do this for a few sec. Be very careful. I was told they can come apart doing this.
It has never happen to me and I've done a lot of them.
They will then again take a charge.
The newest battery's have electronics inside. I have not messed with them.

I have some I'm going to try that on. Just have to see which one is + and-- on the batt.
Thanks.

Put it back on the charger for a few min. That will give it enough charge to put a meter on it to find the post post.

[Jim_Rogers]

I had two batteries rebuilt for my portacable power drill at Batteries plus place not to far from me.
One of them I had to take back twice to get them to fix an internal connection that kept breaking off for no reason.
But since they were replaced they seem ok.

Jim Rogers

[21incher]

I purchased a Makita 18 V Li Ion set a little while ago and would never purchase another. The batteries just die with no warning. You place them in the charger and lights start flashing and they will never charge again. This was after just owning the set for a little over a year.

[Kbeitz]

I purchased a Makita 18 V Li Ion set a little while ago and would never purchase another. The batteries just die with no warning. You place them in the charger and lights start flashing and they will never charge again. This was after just owning the set for a little over a year.

If they do that put them on a car charger for a short time.
That will fix that problem.

[snowstorm]

I purchased a Makita 18 V Li Ion set a little while ago and would never purchase another. The batteries just die with no warning. You place them in the charger and lights start flashing and they will never charge again. This was after just owning the set for a little over a year.

mine did the same thing. if i am real lucky they last a year

[clearcut]

If they do that put them on a car charger for a short time.
That will fix that problem.

Have a fully charged fire extinguisher at hand. Overheated Lithium Ion batteries can burst into intense flame. Lithium ion chemistry is more complex and potentially dangerous than Nickel Metal Hydride or NiCad.

LiOn batteries are also more difficult to rebuild. Each has a charge controlling circuit board that is matched to a brands charger.

[scsmith42]

Has anyone done this? I lost one of my Milwaukee batts this summer, and I was going to retool with Makita, as they seemed to be the popular choice at work. My boss gave me his old Milwaukee tools, with a bunch of dead batteries, so I bought a couple of new ones and now seem to be committed to Milwaukee tools. The more people I talk to, the more support I get for Milwaukee, although I think Makita would be fine, too. I now have a bunch of batteries that won't take a charge, and I was thinking of rebuilding them.

Dave, I have rebuilt several battery packs.  Here is what I've learned:

1 - you can rebuild NiCad and Nickly Metal Hydrade battery packs.  You can't rebuilt Lithium Ion packs because the electronic circuitry inside must be matched to the batteries.

2.  Cells are pretty inexpensive, but it's hard for an individual to solder them in such a way that the connections don't take up more room than OEM.  If the pack has some room inside, this is not a problem.  However if the pack is very tight, it can be a pain.  I recently had to discard a battery pack because I could not get the connections as tight as what came in it to where the new pack would fit back inside the tight housing.

3 - Buy the batteries that have the tabs on them - much easier to solder them together.

[gspren]

   I have had good luck getting batteries rebuilt at a local shop, 14V Makita, both times the rebuilt battery was better than the original. (more Amp-Hrs).

[Dave Shepard]

At this point, I don't think I'll bother. HD has an M18 Fuel kit with hammer drill, impact driver, and two 5.0 batteries for $399, with $150 credit towards another Milwaukee product. That is to enticing to pass up.

[Brucer]

Don't mess with Lithium Ion batteries.

- They are meant to be charged in two stages ... constant current to start with, then constant voltage.
- If you overcharge them, you are risking thermal runaway which will destroy the battery and will often set it on fire.
- If you expose them to excess heat, they will short internally, causing thermal runaway.
- If you short them, they will overheat, causing thermal runaway.

Each battery contains an electronic circuit that is tuned to that specific battery. This is what controls the charging.

The batteries will deteriorate over time, even if you don't use them. You can slow this process down by keeping them cool. I store spare batteries in a plastic container in the fridge.

Ordinary Lithium Ion batteries shouldn't be charged in temperatures is below freezing. Doing so will cause a metallic barrier to form inside the cells, greatly decreasing the life of the battery.