Milwaukee Responds to the new Dewalt Flexvolt battery system

In recent years the power tool industry has been progressing at an insanely fast pace and manufacturers are trying their hardest to maintain a lead by one-upping each other. For example when it comes to cordless power tool 18V batteries, it wasn’t that long ago that a 3.0 ah battery was considered large capacity, then soon after 4.0 batteries were announced, then 5.0 ah and finally when 6.0 ah batteries were arriving, Milwaukee one-upped the competition by leap frogging past 7 and 8 amp hour batteries with their own Milwaukee M18 High Demand 9.0 amp hour 18V battery. Unlike previous high capacity 18V battery designs where manufacturers would use 10 cells in parallel, Milwaukee’s latest M18 9ah High Demand battery uses 15 battery cells in parallel to produce 9 amp hours of capacity and runtime. Note: Amp Hours are a measurement of capacity and runtime, not a measurement of power output.

Then recently Dewalt offered a new Flexvolt battery that can be used on their 20V Max Dewalt power tools with 20V being a fancy way of saying 18V, and their new Flexvolt batteries also run 15 cells in parallel to increase battery capacity, just like the new Milwaukee M18 High Demand 9.0 batteries. These new Dewalt Flexvolt batteries come in two varieties, one in a 20V 6ah model and a 9ah amp model. Of course they also have a trick up their sleeves as these batteries are Dual Voltage batteries as they can power current Dewalt 20V cordless power tools along with new Flexvolt 60V making this a dual voltage battery. When the battery is installed in a Dewalt 20V cordless tool, it automatically switches into parallel battery cell mode to produce 20V (really 18V power) at either 6ah or 9ah depending on the battery capacity, and automatically switches to series battery cell mode when plugged into a Dewalt Flexvolt 60V cordless tool at either 2ah or 3ah depending on battery capacity. These new Dewalt Flexvolt batteries can also power 120V Dewalt Flexvolt power tools such as their two 120V 12″ miter saws with the use of Two Flexvolt batteries (60V X 2 = 120V).

One of the main benefits of 60V and 120V cordless power tools is that the additional voltage generally means a more powerful power tool and naturally should be more powerful than lower voltage tools such as 18V or in Dewalt’s case 20V max. Many of Dewalt’s latest 60V and 120V cordless power tools are claiming to offer increased power and performance compared to 18v models and that’s where Milwaukee comes in where they respond to the new Dewalt Flexvolt battery platform with their latest ad/campain shown below. Their campain is called “VOLTAGE …is only part of the story”. To check out the full campain in detail, check out the Milwaukee webpage here.

Milwaukee high demand vs Dewalt Flexvolt

In the Milwaukee “VOLTAGE …is only part of the story” ad, Milwaukee challenges the new Dewalt Flexvolt with a side by side comparison between the new Dewalt Flexvolt battery compared to Milwaukee’s own High Demand 9.0 ah battery. In my opinion, Milwaukee did a good job on the surface to compare the two battery systems but a deeper look reveals bias on the part of Milwaukee to the advantage in Milwaukee’s direction. The biggest problem I see is that the comparison is not apples to apples and I’ll tell you why. While their comparison making the Dewalt Flexvolt battery shown appear to be inferior when it comes to their points such as less work per charge – are true, they are comparing the M18 High Demand battery to the smaller capacity Dewalt Flexvolt battery that uses fifteen 2.0 ah battery cells and is rated at 6.0ah at 20V. In essence their comparing a battery that stores 15 x 3.0ah cells (Milwaukee M18 High Demand 9.0) vs 15 x 2.0ah cells (Dewalt), and of course the Dewalt battery shown would have less runtime. That’s like comparing two cars with all things being equal, and saying that the car with the larger gas tank will yield more miles per tank.

I feel a fair comparison would have been the Milwaukee M18 High Demand 9ah VS the Dewalt Flexvolt similar capacity battery that’s also rated at 9ah at 20V (18V). In that comparison the numbers would be more on equal ground as the Dewalt Flexvolt 9ah battery at 20V also has the same count of battery cells at 15 total with each cell with a rated capacity of 3.0 ah. I am unsure of the total Wh (watt hour) rating for the new Dewalt Flexvolt battery with 9ah at 20V, but I would assume it’s somewhere very close to the Milwaukee M18 High Demand 9.0 ah rating of 162 Wh.

Some claims are true such as the points said about the Dewalt Flexvolt platform has a smaller system. Completely true facts at the moment as the Dewalt Flexvolt 60V and 120V cordless power tool line have barely been announced and the new lines are just getting out the door with a small handful of cordless tools to choose from. The fact is that all new cordless power tool lines start out small and new cordless tools are added making the system larger over time. What Milwaukee didn’t list on the comparison was that the Dewalt Flexvolt batteries are backwards compatible with Dewalt 20V tools adding to the availability of cordless power tools to the Flexvolt battery.

Another point where it’s said that the Dewalt 20V power tools with 60V Flexvolt packs do not offer 60V performance is also true as the Dewalt Flexvolt batteries will pump out 20V when inserted into 20V max power tools. This statement is also true but Dewalt never claimed that their Flexvolt batteries will provide 60V power to existing 20V tools, they simply provide 20V power when connected to Dewalt 20V power tools and provide 60V Max power when connected to Dewalt Flexvolt 60V Max power tools.

The bottom point was the claim that 20V packs do not work with 60V tools. Again, here is another fact as the Regular Dewalt 20V Max batteries that are not Flexvolt batteries, will not work with Flexvolt 60V tools. This could add to user confusion and also adds incompatibility when users have many regular 20V Max batteries and start adding Dewalt Flexvolt 60V and 120V power tools. They would need to purchase additional Dewalt Flexvolt batteries that are compatible with the new Flexvolt power tools.

Bottom Line

In my experience more voltage does mean more power as I have seen this in the many cordless power tools I have tested and reviewed. This is the general rule of thumb although there are variables as the strongest performing power tools in a lower voltage can be more powerful than the lowest performing power tool in a higher voltage. For example, this applies to pro level 12V tools that outperform budget DIY level 18V power tools BUT when it comes to pro level lower voltage tools compared to higher voltage pro level tools the difference is noticeable with more power on the higher voltage tools.

But then again Milwaukee is doing some amazing things that users would not have expected from 18V power tools such as the introduction of the M18 Fuel grinder with performance similar to corded models, and recently they announced an 18V SDS Max rotary hammer that takes advantage of the new M18 9.0ah high demand battery. Then this year at the Milwaukee 2016 new product symposium event where they showcase their latest tools, they announced new 18V outdoor power equipment with performance similar to higher voltage tools. For example, their M18 Fuel brushless string trimmer shown at the event uses dual line 0.80″ or larger 0.95″ line with a 14-16″ cutting swath (note: keep in mind that the string trimmer stats may change with the final production model). With those kinds of stats, it puts it right there with the best of 56V & 58V outdoor power tools. So Milwaukee has something up their sleeve that’s taking advantage of their new M18 9.0ah High Demand batteries while giving what seems to be performance only seen on higher voltage platforms. Never would we have guessed they’d pull any of this off on 18V power tools. Even their recently announced M18 Fuel 10″ miter saw confirms this as most 18V miter saws are using 7-1/4″ blades with the largest blade of the 18V bunch using an 8-1/2″ blade.

While Milwaukee’s latest 18V power tools that have been announced are doing wonderful things with 18V, my past experience with 18V VS higher voltage platforms is that I can usually expect more power out of a higher voltage. For example while both the Milwaukee M18 Fuel 7-1/4″ and Makita LXT X2 7-1/4″ circular saws are both top of their class for cordless power saws, I could easily feel more power on the Makita X2 because simply put it’s running on a higher voltage at 36V vs the 18V on the Milwaukee (check out the comparison here).

Milwaukee says that their M18 9.0ah High Demand battery will provide up to 2x the performance when used on their M18 power tools, I would assume nearly twice the amount of runtime with the possibility of a slight bump in power tool performance, but on the other hand I expect more power from a 60V power tool such as the new Dewalt Flexvolt 60V Max power tools because if they don’t, something is wrong in the picture. Dewalt seems to be taking full advantage of the 60V system with a large capacity 6″ angle grinder and reciprocating saw that claim power similar to high powered corded models along with tools usually only found on corded such as a new 60V table saw and massive 120V 12″ miter saws.

I do like where Dewalt is taking their approach where we have two new cordless platforms (60V & 120V) and use a battery that is compatible with both along with existing Dewalt 20V cordless power tools. This provides an easy upgrade path to current Dewalt 20V users wanting more power than can be experienced on 20V/18V tools and want the additional performance and runtime of higher voltage cordless power tools. But this does come at a slight price as users would have to purchase new Flexvolt batteries to take advantage of the new higher voltage power tools coming from Dewalt.

Personally I like Dewalt’s direction and would think it’d be a great idea if Milwaukee followed suit but Milwaukee’s approach is also very well executed with taking full advantage of their new M18 9.0ah High Demand batteries on cordless 18V power tools such as the M18 Fuel SDS Max rotary hammer, M18 Fuel 10″ miter saw, and new M18 Fuel outdoor power equipment. But hopefully Milwaukee also follows the example set by Makita and Dewalt by creating some seriously powerful cordless power tools using 2 batteries to double voltage such as Makita’s X2 cordless power tools and Dewalt’s Flexvolt 120V miter saw.

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8 Comments on "Milwaukee Responds to the new Dewalt Flexvolt battery system"

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In case you haven’t noticed Milwaukee gives their marketing department a lot of latitude.

Tom panousis
Dewalt’s flexVolt is a completely new battery platform wich happens to be backwards compatible. That said, I think that putting a large battery like that on a 20 volt max tool is kind of defeating the purpose. People don’t want to have to work with such a heavy load all day. As a new platform though, I think it shines, they got one up on Milwaukee. Milwaukee need not worry though, their answer is right in front of their eyes, I am surprised no one in the Milwaukee camp has seen this. All Milwaukee has to do is revamp their… Read more »
Benuel K King

Great job to however did the story,

I am power tool manager in a local hardware store, and see the fine print stuff when it comes to the warranty and so on, Dewalt we get a lot better service, and also a smaller percent of the tools come back under warranty…. And also comparing the price the Dewalt 2 pk. Flexvolt retails for the same price as 1 9amp. Milwaukee battery.


We have heard that not all flex volt batteries will work in older 20v tools I like the idea of the power cord adaptor for the mitre saw but that battery is so big and heavy I think I’ll sit back and wait a year to see how it plays out the Milwaukee has a lot of neat features that Dewalt didn’t take up on Milwaukee’s chop saw is all new Dewalt s is a corded conversion like I said way and see


It’s all about the voltage, as you increase the voltage you will increase the torque, that’s why the Dewalt Flexvolt slider saw is every bit a good as the corded version. As voltage increases current decreases for the same amount of power. Dewalt has this contest beat hands down.


It is not all about the voltage. The power that an electric motor can generate is calculated by the Voltage times the Current. (And to a lesser extent, times the efficiency of the motor and electronics.)
To some extent, you can add more voltage to an existing motor system, and get more power, though things will wear quicker. And of course, if you give it too much voltage, the magic smoke can escape and you have a dead tool.