Milwaukee M18 chargers light up in a few different ways based on what’s happening. The most usual patterns are solid red and green, that symbolize ongoing and full charging respectively.
Before you continue reading this article, you can first watch the short video I made about this topic. It discusses the two types of blinking red light on Milwaukee M18 battery charger.
First is the fast blinking red light which means the hot cold delay is triggered. To solve this issue, just wait for the battery temperature to return back to normal then try to charge it again.
Then, there’s the slow blinking red light which means battery charging is pending. There is nothing you should do on this case but just wait for the other battery on the Milwaukee M18 battery charger to become fully charged.
One of the rarer patterns though, is a blinking red light. Does your Milwaukee M18 battery charger only show you that blinking red light when you’re trying to use it? Here’s why:
Read: Milwaukee Charger Making Hissing Noise: Why and Where Does It Come From
Milwaukee M18 Battery Charger Blinking Red Only – Explained
There’s some confusion about this specific pattern on the Milwaukee M18. The main reason why that confusion is there, is because there are actually two different ways the light can blink red.
Most patterns on a Milwaukee M18 charger are distinct and easy to tell apart. These ones are so confusing because they’re nearly identical to one another. But, they’re also important.
I’ll talk about each of them differently so you don’t have a problem understanding either one. I’ll start with…
Milwaukee M18 Charger Blinking Red Rapidly
Out of the two blinking red lights, the more common one is the rapid blinking. In this case, the light switches between red and no color super fast, with no pause.
Whenever you see a fast blinking red light on the Milwaukee M18 charger, that means the battery is overheating or too cold. The pattern is warning you about unsafe temperatures.
The charger has a little sticker on it that explains this, which you can see up there. But, if you didn’t read the manual or currently don’t have it on you, it’s easy to misunderstand.
Let me make it clear that you should NEVER try to charge your battery when this pattern shows up. It’s very dangerous for the battery, and can be a safety concern for the user themselves.
Regardless of the temperature of the battery, your job is to bring it back to room temperature. Luckily, that’s easy to do! All users need to do is to leave the battery in a safe environment.
Put it in a room free of heat or cold exposure for a few hours, and it’ll be safe to use again! Once the temperature is back to normal, it won’t trigger the rapidly blinking red light anymore either.
Milwaukee M18 Charger Blinking Red Slowly
A slowly blinking red light on the Milwaukee M18 charger is much rarer than the rapid one. That’s because this light only triggers when you have two batteries on the charger.
When you put two batteries on these chargers, they’ll only be able to charge one of them at a time. The latest connected battery will have to wait its turn before getting charged.
Related: Common Milwaukee M18 Battery Charger Problems
So, one of the batteries will have a light that shows solid red, indicating normal charging. Meanwhile, the battery that isn’t being charged currently will flash red slowly.
Putting it simply, it just means that your battery’s charging is pending. It’s waiting for its turn to charge while the other battery reaches 100% power first.
Related: Common Milwaukee M18 Battery Problems
There aren’t any problems going on, and you don’t have to worry about anything. After the current charging battery is at full power, it’ll switch to a solid green color.
When that happens, the slowly blinking red light will disappear. It’ll be replaced by a solid red light instead, which I told you earlier means charging is going normally!
In fact, here’s a picture of the red light on my Milwaukee M18 charger currently as it powers one of my batteries.
So, simply leave the charger if it blinks red slowly as it’s a normal charging light that goes away once your battery reaches its turn for charging.
