My Milwaukee M18 battery gave up on me recently and wasn’t charging no matter what I tried. I kept tinkering with it instead of tossing it aside and buying a new one, though.
That ended up being a pretty good decision too, because I was able to reset my Milwaukee M18 battery and get it back to power up even without the charger. Let me share how below!
But before you continue reading this article, you can first watch the short video I made which shows how you can reset a Milwaukee M18 Battery without a charger.
You can do this in three ways: first by using another Milwaukee battery, second by using a battery from a different brand but with similar specs, or lastly by using a DC power supply.
3 Ways To Reset A Milwaukee M18 Battery Without A Charger
Method 1: Use Another Milwaukee Battery
I tend to buy packs of batteries instead of buying singular ones. That way, I get to keep a few spares around in case I run out of charging or something. Those spares are pretty helpful for this situation!
Anyone that has an identical spare Milwaukee battery will find it really easy to reset a problematic one. That’s because you can use the spare to reset the faulty battery by jumpstarting it.
Since both batteries are identical and have the same specifications, they also have the same requirements. So, if you have a spare, start by charging it to 100% of its power.
Put the problematic battery next to the working battery once it finishes charging, and connect them using cables. Here’s a picture of both my Milwaukee batteries from when I did the same thing.
You’ll need two wires like I’m using. One wire will connect the positive terminals of both batteries together. The other wire will do the same thing but for the negative terminals instead.
Don’t connect opposite terminals together unless you plan on frying your batteries. Another thing that’ll fry the batteries is if you keep them connected together for too long.
I think 15 seconds should be more than enough to reset your faulty Milwaukee M18 battery. Disconnect the cables from the terminals after that much time passes.
This whole process should’ve kicked up the voltage in its cells and revived it. Now when you try charging it and using it on your tools, it should work just fine.
Related: Reasons Why Your Milwaukee M18 Battery Charger Blinking Red Only
Method 2: Use A Different Brand’s Battery
Even if you don’t have a spare Milwaukee battery, it might not be a problem as long as you have other batteries.
Even a different brand’s battery will do the job and help reset your Milwaukee M18 battery. The only thing you need to watch out for is the voltage.
I don’t recommend just using any other battery to reset yours. If you’re trying out a different brand, it’s best to use a battery that matches the voltage of your Milwaukee M18.
Since the Milwaukee M18 is an 18v battery, it would be best to use an 18v battery. But, you could use a 20v one and still be on the safe side as slightly higher voltage is still acceptable.
When I tried this method out, I used an 18v Bosch battery along with my Milwaukee M18. You can see both of them connected in the photo above.
The only real difference between this method and the first one is the brand of your functional battery. Other than that, it’s pretty much the same!
All you need to do is use two connector cables to attach both batteries’ positive and negative terminals together. One cable on each positive terminal and one on each negative.
Hold this connection together for just around 15 seconds, and your Milwaukee M18 battery will have reset. After that, you can take the cables out and put it on charge.
Method 3: Use A DC Power Supply
If you have no other batteries, or none that match your Milwaukee M18’s voltage, then the only remaining option is to use a DC power supply. These are great for resetting problematic batteries.
A DC power supply can adjust to and provide the exact voltage your battery needs to jumpstart. If you own multiple batteries, it’s a great thing to keep around because of how useful it is.
I got one for myself because of that and it’s helped me reset my batteries a bunch of times, including the Milwaukee M18! Start by putting a wire in each of the battery’s terminals.
Connect the positive port wire on the power supply to the wire on your battery’s positive terminal. Do the same thing for the negative wires too, like I’ve done below.
With the connection taken care of, you can turn the power supply on. Set the voltage on the power supply to 18v after turning it on, since that’s the voltage of the M18.
Now increase the amp to 1. Do this slowly instead of suddenly ramping it up to 1 in one go. Guide it to the 1.0 amp point little by little, until it finally reaches that stage.
After it’s at 1.0 amp, let the wires stay connected for 15 seconds before turning the DC power supply off. Your battery should’ve reset and will now work!
