The battery cells used in a power tool battery are what can make or break it, and with many of them being manufactured by a small number of companies it can be an easy way to compare and contrast different batteries. So with that in mind let’s open up a new Milwaukee battery and have a look at what’s inside.
This is the battery I will be opening up. A 4Ah M18 Red Lithium battery, purchased on the 12/01/2022. I have popped the date in as the cells used by Milwaukee may change over time.
Here we have the battery with the lid off and the main circuit board of the battery exposed. This is the brains of the battery and is the one area, apart from the cells themselves, where the tool manufacturer can make a difference to the quality of their battery.
You can see all of the different nickel strips going off to each pair of cells, this will be so the battery can be load balanced. Essentially this is just making sure that each cell is at the same voltage which will increase the performance and life of the pack.
Now I have got the pack out of its casing but it is not going to be easy to spot the type of battery used. As you can see the cells themselves are fully covered, which is not common with other batteries I have looked at.
This is a good thing for the health of the pack as it will add a little extra protection to the cells when the pack is dropped and knocked around. It doesn’t help me though when trying to find out what cells are inside!
But what do we have here? I can just make out a little bit of the text on the wrapper of one of the cells and it is exactly what I need.
This confirms that the battery is a Samsung 20R cell. This makes a lot of sense as these are very high-quality batteries and the 20R is a 2Ah cell. So because the pack is set up in a 2 in parallel 5 in series configuration the capacity of each cell is doubled, making up the 4Ah battery.
What Cells Are in a Milwaukee Battery
So in this 4Ah battery, Milwaukee is using Samsung 20R cells. If we look at the DeWalt battery I opened earlier we can see that in that 5Ah battery DeWalt is using the Samsung 25R cells, so very similar but with a slightly larger capacity which is why one battery is 4Ah and the other 5Ah.
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