Lithium Ion Milwaukee Tool Battery

Wow, this is a cool charging tool.

I'd like to buy one, but I'm not sure how often I'd use it.

I think I'm going to try the jump start method first - and of course I'll do it outdoors!

Yes it is very handy to know that the holding capacities of the batteries are similar, before soldering them into a pack...You're only as strong as your weakest link...haha

Keep a bucket of sand handy, because if it does catch fire you don't want to put water on it. And if it explodes, there could be enough force to send parts with a decent distance that could do harm.

Keep in mind that there is electronic circuitry in those batteries so the method used may not work or may damage the circuit. I opened one up and found that although the meter shows the battery is not charging any longer, when tested while disconnected from the electronics, there is a full charge on the batteries themselves. I believe the circuitry may be blocking the truth so that we buy new batteries.

I think the circuit is good. When I put it on the charger, I get a tiny amount of charge and the light on the battery works. I have a feeling the cell(s) are bad.

If you take the cover off of the battery pack you'll find the batteries, when tested independent of the electronics, hold a full charge. I disassembled one and used the batteries in a MagLight and it works fine. But anything is possible.

Thanks for the tip. I was thinking of finding the bad cell and replacing just that cell. Though I could use the good cells for other devices too.

Hi Solar,

Yes, I watched both of these videos. The second one looks like the answer I'm going to use, but it did concern me when he recommends doing this outdoors. I don't like the thought of an exploding pack or one that catches on fire.

The first video is very interesting. The amount of electronics built into the battery packs differs by the manufacturer. Who would've thought there was that much of a difference!

Thanks for the videos.

Hi JE,

I have quite a few Milwaukee cordless tools. I only have one V18 tool - a really neat hammer drill. It feels like a professional model - nice solid keyless chuck and a very heavy tool.

I'm going to try to use one of my M18 batteries to jump start the V18 batteries (one at a time).

Thanks for letting me know you've had success doing this.

No problem. This guy (nut) has at least 40 different Milwaukee fuel batteries and others too. Every type of charger etc.

I saw several batteries that wouldn't charge ...so..

They weren't mine so I had no problem hooking them up and "testing"

Just getting any use out of the old batteries seemed like a victory.

Thank Rixter.

This helps me understand a lot more about Li Ion batteries and how they accept a charge. I've heard that it's not good to charge a Li Ion battery to 100% and that good quality chargers don't allow a 100% charge.

I've used a 12V battery charger, set on 2 AMPS to jolt NiCads and NiMh batteries that wouldn't charge. That worked for me. I've never tried Lithiums, but I don't see why it wouldn't work.

See Rixter's post too. Good answer.

I wouldn't advise trying that with lithium batteries....they are very sensitive to overheating....

The first thing you do is measure the voltage of each cell. If one is very low it may be the fault.
Next find out if all the cells get charged in series or individually.
Then you get a $3.00 USB charger on alligator clips and charge one cell at a time. The lights on the charger will tell you when the cell is charged. It will take a while but all the previous replies are drivel.

Hi Colin,

Thanks for the tip. I believe the cells are charged in series. If one of the cells has a lower voltage, does that necessarily mean that the cell is bad?

Here's another bit of information. The last time I used the tool was two years ago. It's been in my garage and the temp varies from the low 40's in the winter to 95 in the summer. My gut feeling is that the batteries discharged from sitting too long and the charger won't charge it unless I jump start the battery.

Prior to me posting here, I did consider taking the battery apart and testing each cell. I could figure out the voltage by dividing 20V (total voltage of the battery without a load) by the number of cells. Then doing exactly what you recommend. Charging each cell individually and testing to make sure it holds a charge. If one cell is bad, I can replace it - I think I'll be able to find the cell.

I'll keep you guys posted on how it works out.

Thanks

Here's something along the lines I have been advocating:

https://hackaday.com/2010/01/12/makita-battery-pack-repair/

I have a car jump start/charging unit - one of those roller types. I don't think my charger will put out more than 14V or so. The Milwaukee battery is an 18V unit. I don't know if 14V will be enough to "jump start" the battery, so the charger will turn on.

One thing cool about the Milwaukee battery is that it can be taken apart - there are "security" screws that hold it together. I haven't tried to take it apart yet and I think my best bet is to try to jump start it with a charged 18V Li Ion battery.

I'll let you guys know how it works out.

Thanks

https://enerdrive.com.au/2017/11/29/can-charge-lithium-battery-lead-acid-charger/

I have what we term a heart starter which we use for dead Nicads, NiMh batteries but I have yet to try it on Lithium batteries. In a case I have a 50V power supply which charges 160,000 MFd electrolytic capacitor through a controlled charging circuit.

When the light goes on the capacitor is charged and then it is ready to be applied to the offending "sick" battery connected to a volt meter. The capacitor discharges through the low resistance of the battery producing many amperes of current.

After the pulse, if any residual voltage appears on the meter then the battery will accept a charge otherwise it is round two or more until it has a charge or it just isn't going to hold a charge. This is wonderful for blowing dendrites out of NiCad batteries and jolting NiMh batteries as well. Have done this with loads of batteries from emergency lights where the constant trickle charge does not do the batteries any good.

I used to mess a lot with (sealed) NiCds. If I measured the cell voltage and it was exactly zero, it had a whisker grown across.

I charged up a big electrolytic capacitor and shorted it across the dead cell. Many times it would burn out the short and the battery could then be charged normally.

Hi Guys,

I also found this conversion tool. I can convert my V18 tool to use the newer M18 battery. I'm not sure I want to do this yet - I'd like to see if I can get my V18 batteries to accept a charge. Why? I have one V18 tool with two batteries and a charger. I have a half dozen or so M18 tools, each with a battery, but only two chargers. If I'm working on a project that is battery intensive, I want the most chargers I can, so I have more fresh batteries. Yes, I've actually run out of power on some of my jobs, so the more fresh batteries, the better.

https://www.ebay.com/itm/Adapter-Converter-for-Milwaukee-m18-18V-Li-ion-Battery-to-milwaukee-V18-Battery/283668330042?hash=item420bf3363a:g:bRoAAOSwHfxdxQrm

I must be qualified to reply, as I have so much experience in wrecking lithium cells by treating them like NiCads! They are very fussy and delicate little flowers.

There are several different chemistry types of lithium cells, and some are more explosive than others, but all can be killed by overcharging and all can be killed by being allowed to go too flat. For this reason, they all should - and most do - have built-in control circuits which stop external discharge when the voltage drops too low, stop charging when the voltage gets too high, and limit current in and out.

Some battery packs just monitor and control each cell individually, while others - just a few - go to the expense of a cell balancing circuit, which bypasses cells which are already fully charged and allows charging to continue in cells which have not reached cutoff voltage (usually 4.2V).

Once the voltage of a cell has dropped below the low cutoff threshold (maybe 2.7v), charging also is limited by many of these protective circuits, but a trickle charge is still allowed. That means an apparently dead battery, left hooked up to a charger, may revive and accept a normal charging rate after a few hours.

Hooking each cell in turn up to a 4.1V 1A supply and trying to charge it that way is probably the safest way to get it working again (if it is salvageable), without going on to wreck or possibly detonate it by overcharging. It's tedious, but there you go. If you go the USB charger route, then you MUST monitor the voltage and disconnect before it reaches 4.3V, or you will kill it. Trying to revive it by charging the whole string, with 18V or whatever, will almost certainly end up overcharging some cells and thus wrecking the whole thing - unless it is fitted with a balancing protection circuit, which I rather doubt.

I can answer these questions from a different angle with the little knowledge I have on researching cutting edge Lithium ion (or other element) batteries.

The more power that is stored in a small space requires that the components become thinner/lighter. so for example a separator that is used to separate the positive side of a battery from the negative side becomes thinner and thinner (it also needs to be porous)

as a battery is charged/discharged, certain physical changes can happen inside a lithium battery, one such change is the formation of dendrites which can and do perforate the separator. once this happens the cell is shorted out. by "jump starting" a battery forces lots of energy to melt these dendrites and can be a recipe for disaster depending on the size and location of the dendrite.

as far as flammability goes, remember, lots of power in a small package which demands fast discharge ("C" rating) to power these high torque motors. so the way the energy is stored has an effect as to the way it is released. For a visual, watch the way black powder burns in atmospheric conditions. it burns faster when the particles are smaller, and then compare to smokeless powder.. much more energy packed into less volume. So lots of energy can be released when shorted out very quickly, and to add to that, the electrolyte is a flammable liquid. But I must say, lots of work has been done on using less or non-flammable electrolyte. Lowering the flammability of the electrolyte produces a much safer battery, but still lots of energy is released upon a short which can runaway due to heat (such as melting away the intact separator).

and to address the 3rd remark stating that the fire department stood and watched, well this is because lithium reacts very violently with water and spraying any type of hydro-based product can intensify the fire.

I would just buy new batteries.. or if you have access to an ultrasonic welder, and are handy, you can replace the batteries internally and rebuild the pack.

I haven't had time to "jump start" my battery packs yet.

After reading some of the posts - Thank you to those who helped - I'm going to do this with a nice pile of sand on a tarp, just in case the battery pack catches fire.

Another observation: My battery pack has those tamper resistant screws holding the pack together. I have a bit for the screw head, so I'm thinking it may be a good idea to take the cells out and check them one by one.

Lastly, I did try to run them on the charger again. After about an hour, I pulled the pack off and put it on the tool. I only get a slight movement in the motor - won't even turn 1/16 of a turn. Just tries to move and stops. After a few tries, the battery is too low to even make the motor move a little.

Haven't had time to unbend a couple of paper clips?

Wow! You are busy.

I'm concerned about the pack blowing up or catching on fire. So I put it on my list of experiments and it gets a back seat to important things.

What I wound up doing is I used my corded demolition tool Milwaukee Demolition Tool

I had to drill holes in the concrete slab. I have the V18 powered Hammer Drill, which is an awesome tool, but with two dead batteries, it's of no use and the battery packs are very expensive - obsolete. So, I used my demolition tool and bought an SDS concrete drill bit. Worked beautifully! I drilled about 20 holes total.

Why was I drilling holes in my slab? I replaced the floor in my kitchen (took the laminate out and put in porcelain tile). The threshold had to be attached to the slab, so I drilled holes, then pounded a wood dowel in. Then I nailed the threshold to the dowel. I also repaired a section of my laminate flooring in the hall next to the bathroom. The bathroom had a leak and water got under the laminate and it wound up chipping/cupping. So I pulled the old flooring and installed something that's close. The transition needed a threshold looking piece, so I did the same as in the kitchen.

It came out looking really good. And it's in nice and tight. Tenantproof!!!

I have dismantled and tested some hundreds of lithium ion cells. Obviously I have found some to be dead and tried to "jump start'' 'em using other charged but less potent cells in order to limit current and voltage.

I managed to start charging on most dead cells but afterwards I realized the battery rating did not worth the effort. For any of the '"revived" cells.

It's a good activity to experiment with. Not good if you want to get a useful battery;

Nikolay, thanks for the info. I had a feeling the battery pack wouldn't be of much use after the "jump start". I think I'm going to give it a try, with the expectation that I'm going to have to put new cells in the battery pack.

Well, it is now March.... and you have not followed up with results. I certainly hope you are ok, and did not have a thermal runaway event.

Though silly on a practical matter, but very interesting on the curiosity aspect of "will this work", you have to take some things for granted:

Milwaukee, Dewalt, Makita, and others on most current lines of cordless tools; electronically key the batteries and charger to one-another.

Li-Ion come in many flavors, unlike the fairly singular characteristics of Ni-Cad. The chargers often are monitoring charging and temperature of the cells, and if you used a tool down to the auto-shutdown ( Li-Ion do not recharge correctly when you pass a threshold of discharge ), and the batteries then dropped severely in temperature, you could have surpassed the drop-dead discharge level, where the Charger will flag the battery..... such that it will refuse to charge in any charger. If you rewire and eliminate the protections in your chargers and batteries.... be sure to have a separate, steel structure just for battery charging.

All these safeties that we all pay for to be built-in, the rest of us suffer paying for, just to keep you alive!

So the sand pit is a start, but a blast shield might also be advisable.

Setting the humor aside... if your experiment works, you now have a non-regulated charging circuit..... and a much higher likelihood of overheating and setting up a neat-o fire! As long as the fire is not in your house or garage. not much problem.

If I am way off on the science of this topic, blame it on AvE. I gleaned almost half of what I think I know on his videos.

I hope you are still with us, to reply!

I finished my project and I haven't needed the tool, so it's sitting in the garage. Unfortunately, other projects have come up that are more important, but it's on my list of things to do.

I'll keep you guys posted.