How to Fix a Milwaukee Battery

You can do a few things to fix a Milwaukee battery.

First, check whether the outlet has power, the charger is working, the terminals are clean, and you’re charging it correctly. You should see a red light while it charges and a green light when fully charged. If it fails to charge properly, Milwaukee recommends completely unplugging and disconnecting the charger and waiting 10 seconds before re-plugging it.

If the battery appears dead, I’ve also described a ‘jump start’ method you can try below.

A Milwaukee Battery

milwaukee m18 red lithuim battery
Video | KonaBlueSVT

A Milwaukee battery is typically a lithium-ion battery.

A lithium-ion battery gives greater power than a traditional non-lithium-ion battery and has a longer lifetime. They come in different capacities and are ideal for cordless tools.

Charging a Milwaukee Battery

Are you charging your Milwaukee battery properly?

First, ensure you’re charging it correctly because if it’s not done properly, the battery might be okay, and you won’t need to fix it.

Here are a few things to ensure:

An indicator light should appear on the charger when plugging in a Milwaukee battery. Usually, it’s a solid or flashing red light while charging and a solid green light when charged. You might need to press the two red buttons on the battery’s sides while sliding it along the charger. When pressed, you should hear an audible click.

a Milwaukee battery’s buttons
Video | KonaBlueSVT

Also, check the connection between the battery and the charger’s terminals. The battery must be placed properly on the charger, and it should be secure.

Battery Symptoms and Causes


You may need to fix a Milwaukee battery if you notice one or more of the following symptoms:

  • The battery doesn’t appear to charge at all.
  • The battery doesn’t charge properly:
    • The battery shows a red (or flashing) light while charging.
    • The battery shows a green light but doesn’t charge.
    • The battery takes longer than normal to charge.
    • The battery fails to hold a charge for a long.
    • The battery charges only for a short while and then stops.


A failing battery has several possible causes.

The most common causes are related to age, damaged cells, overheating, and a memory effect. If the battery itself is fine, the problem might be with the battery charger.

I will cover these in detail later. But identifying the problem is always the first step before solving it. Once you are sure the problem is with the battery, proceed to fix it.

Fixing a Milwaukee Battery

You can only fix a Milwaukee battery if it’s not damaged or expired and need replacing.

Fix a Milwaukee battery by doing these checks.

Symptom 1: Battery not Charging

If the battery doesn’t appear to charge, check the charger and whether the power outlet is working.

The battery can only charge if it receives power. It might be that the battery is fine, but it’s not getting any power.

You can plug another device into the outlet to see if it works. If you suspect the outlet is not working, try another outlet. If the battery charges, continue charging it and fix the other non-working outlet. The problem might be a loose connection, burnt fuse, tripped breaker, etc.

If the outlet is working, check the charger. Do you notice any damage? Does it only work if you move the wire? In either case, you probably need to buy a new charger.

Symptom 2: Battery Doesn’t Charge Properly

Several symptoms can show if the battery doesn’t charge as expected.

The battery might show a red (or flashing) light while charging, a green light that doesn’t charge, takes longer than normal to charge, fails to hold a charge for long, or charges only for a short while and then stops.

Here’s what you can do:

If you have another Milwaukee battery, try charging that from the same outlet using the same charger. If the second battery charges properly, the first battery is faulty, damaged, or expired.

If the second battery doesn’t charge properly, and you get the same indicator lights, the problem is most likely with the charger.

There might also be a coincidence that you have two faulty or dead batteries, but if you’re sure the second one is fine, then suspect the charger.

Symptom 3: Connections Need Cleaning

The charger will not be able to charge properly if too much dirt accumulates on the battery’s terminals.

You can only ensure a good connection if the terminals are clean. Use a Q-tip and rubbing alcohol to clean them.

Testing the Battery

You can do a few more things to check the battery if you find it difficult to charge.

If you see the red and green lights flashing on the charger, unplug it and wait ten seconds before re-plugging it.

If the lights still flash, Milwaukee recommends unplugging the charger again and completely disconnecting it from the power source. The lights might flash for a few seconds before the charger powers off.

Wait for 10 seconds before reinserting the battery and plugging in the charger.

If the red light comes on and stays solid, you’ll know that the battery is charging.

Working with a Dead Battery

If you have what appears to be a dead battery, all hope is not lost.

There’s one more thing you can try if you have another working battery. It might just help to revive the first one. In this method, we will ‘jump start’ the first battery, like you would with a dead car battery.

First, check the voltage of the healthy battery. If it’s around 20 volts, as shown, it’s fine.

Now place the two batteries next to each other and connect the like terminals using a couple of wires. So, connect the two positive terminals with one wire and the negative ones with the other.

You must do this right.

Hold the two wires in place for about 15 minutes. This should be enough to revive the problem battery.

Now disconnect the wires and try charging the problem battery on the charger again. If you get a solid red light this time, the battery has revived, and this method succeeded.


New/Good Milwaukee Battery.

Video References

Doctor Lefthandthread


Silver Cymbal

How helpful was this article?

Were Sorry This Was Not Helpful!

Let us improve this post!

Please Tell Us How We Can Improve This Article.

About Alex Robertson

c3c9d43f1f0d14c4b73cb686f2c81c4e?s=90&d=mm&r=gCertifications: B.M.E.
Education: University Of Denver - Mechanical Engineering
Lives In: Denver Colorado

Hi, I’m Alex! I’m a co-founder, content strategist, and writer and a close friend of our co-owner, Sam Orlovsky. I received my Bachelor of Mechanical Engineering (B.M.E.) degree from Denver, where we studied together. My passion for technical and creative writing has led me to help Sam with this project.

| Reach Me