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What is Milwaukee M18 FORGE and Why Should You Care ?

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Milwaukee Tool recently showed off their new M18 FORGE battery technology, and it’s going to be a game-changer.

We had been expecting to see new Milwaukee M18 batteries with Li-ion pouch cells. And, that’s exactly what we have, with this new XC 6Ah battery. But, that’s not what Forge is about – Milwaukee Forge is bigger than that.

In Milwaukee’s words, REDLITHIUM FORGE increases the capabilities of the M18 and MX FUEL systems, providing the most power, the fastest charging, and the longest life without sacrificing compatibility.

Milwaukee’s M18 Forge XC 6Ah Battery

Milwaukee M18 Forge XC 6Ah Battery

Milwaukee’s first M18 RedLithium Forge battery will be an XC 6Ah battery, featuring upgrades all-around.

To start off, the Forge XC 6Ah has upgraded plastic construction that is resistant to common oils, greases, and solvents.

The built-in charge level fuel gauge is all-new, not only for improved durability but easier visibility in sunlight.

The M18 Forge battery also has a new ingress coating that provides increased protection against the weather and jobsite conditions. Weep holes at the bottom give water a place to drain out of.

A similar ingress coating has been applied to the also-new MX Fuel Forge battery packs.

Milwaukee M18 Forge XC 6Ah Battery Pouch Cell Parts Breakdown

The XC 6Ah battery will feature pouch-style Li-ion battery cells.

You will not see this emphasized – or even mentioned in most product or sales pages – because Forge will encompass multiple battery technologies.

An upcoming Forge 12Ah battery pack, which was only touched upon, will feature tabless cylindrical cells – similar to the ones used in Milwaukee’s next-generation MX Fuel batteries.

Why this is a Major Turning Point

In the past 15 years or so, there have been just two major generational upgrades with respect to cordless power tool batteries.

First, brands shifted over from NiCad and NiMH to Lithium-ion. Improvements followed, such as in charge capacity and tolerance to cold temperatures.

For several years, tool brands introduced higher capacity batteries until a practical limit was reached with 18V 5Ah batteries. Some brands do offer 6Ah batteries built with the same technologies, but with diminished benefits.

In 2015, Milwaukee announced a new M18 High Demand battery with 50% higher cell count. Until then, most cordless power tools had 5 or 10 Li-ion cells. With the M18 HD 9Ah battery, Milwaukee went to 15 cells.

In 2018, Milwaukee launched their High Output line of batteries.

Milwaukee’s M18 High Output batteries were built using larger Li-ion cells that delivered more power and higher charge capacities. This led to a new generation of higher powered tools that users could operate for longer.

While the M18 HD batteries bumped things up a step, the HO batteries took things to new levels.

FORGE is going to do that again.

What happened every time Milwaukee introduced new battery technologies? New and higher powered and more demanding cordless power tools followed. You can be sure the same will be true here.

Other cordless power tool makers have also introduced new battery technologies, and I’m sure they’re not done yet. Competition is sure to drive innovation across the industry.

What does Milwaukee M18 Forge Mean for You?

Milwaukee M18 Forge 6Ah Battery Claims

With this new Forge XC 6Ah battery, you get:

  • High Output 12Ah Power in a Smaller Size
  • 15 minute charge to 80% with the new SuperCharger
  • Longest life compared to earlier battery technologies
Milwaukee M18 Forge 6Ah Battery Power Output and Smaller Size vs 12Ah

The new XC 6Ah battery – with its pouch-cell Li-ion battery technology – is 30% smaller and 40% lighter than the High Output HD 12Ah battery.

With High Output 12Ah-equivalent power delivery, this means that you can use the new M18 Forge XC 6Ah battery in more demanding tools with less arm fatigue – and without worrying about a potential drop in performance or the tool bogging down.

Milwaukee M18 Forge 6Ah Battery Charge Time Comparison Charts

With new dual-port SuperCharger the Forge 6Ah battery can recharge to 80% in just 15 minutes (when charged at room temperature), and 100% in 25 minutes.

Milwaukee M18 Forge 6Ah Battery Longer Life Claim

Milwaukee says that the new Forge 6Ah battery delivers “the longest life of any battery on the M18 system” while maintaining full system compatibility.

How Forge Compares

Milwaukee M18 Battery Power Tiers RedLithium High Output Forge

Milwaukee’s M18 batteries all fit into one of three categories – RedLithium, RedLithium High Output, and RedLithium Forge.

As mentioned, the Forge family batteries will deliver the most power, fastest charging, and longest life.

Milwaukee M18 Li-ion Battery Power Scale

Milwaukee is also describing their batteries according to a new Power Scale:

  • PWR 1
  • PWR 2 (XC 5Ah)
  • PWR 3 (XC 6Ah)
  • PWR 4 (HD 12Ah, Forge XC 6Ah)

Power 1 likely includes compact batteries, like the CP 2.0 battery. Power 2 includes the XC 5Ah, and from what has said in the past, the compact HO batteries, such as the CP 3Ah and 4Ah batteries. Power 3 includes the HO XC batteries, such as 6Ah and 8Ah, and the now-discontinued HD 9Ah battery. Power 4 includes the HD HO 12Ah battery and the new Forge XC 6Ah.

This seems like a simplified way to categorize all of Milwaukee’s M18 batteries. I wonder if a similar system will be used to categorize their tools as well, so that users can always know which tools and ideally paired with different batteries.

It’s worth reminding readers that all Milwaukee M18 batteries fit all M18 cordless power tools.

I have used lower power and capacity batteries on heavier duty tools, and they’ll work for many tasks, but differences will become apparent during demanding tasks. Similarly, the highest capacity battery – the HO 12Ah – is not an ideal fit for more compact tools, with respect to size, weight, and balance.

That’s one of the reasons the new Forge XC 6Ah battery is so exciting – it delivers 12Ah power, but in a smaller and lighter package. It won’t match the runtime of the 12Ah battery, of course, but there are a lot of times when size and weight are higher priorities.

And with the new faster charging speed, you can back to work rather speedily.


This is not first time that we have seen improvements in power deliver and features without an increase in charge capacity. Similar happened when compact High Output 3Ah and 4Ah batteries matched the power delivery and charge capacities of older 3Ah and 4Ah batteries.

We’ve only touched the surface here. I made it a point to learn as much as I could about the the Forge tech. While this post focuses on the M18 battery advancements, Forge tech will be coming to the MX Fuel line as well.

Let me know if you have any questions, and I will try my best to answer them.