Milwaukee first announced their new M18 High Demand 9.0Ah battery pack last year, and although it has been delayed, it is nearly ready to launch.
The new Milwaukee M18 HD battery pack is designed to power their heaviest duty cordless power tools, such as the new M18 Fuel 10″ sliding miter saw.
Just a few weeks ago, Dewalt announced their new FlexVolt technology, which includes a novel battery pack design, a range of 60V Max power tools, and 120V Max dual-battery power tools that can also be powered via an AC adapter. Dewalt FlexVolt battery packs are backwards-compatible with the brand’s 20V Max power tools and chargers.
Read more about Dewalt FlexVolt here, or check out these recent stories:
- Dewalt FlexVolt Introduction
- Dewalt FlexVolt Q&A (More Details)
- Hands-on with the New Dewalt FlexVolt Cordless Saws
- Dewalt FlexVolt Brushless Circular Saw First Look
- Dewalt FlexVolt Saw Intro Videos
The two heavy hitting brands are taking very different approaches to work towards the same goal – a cordless jobsite.
Which is better? This is a question a lot of pro tool users are asking right now, and I’ll tackle the question as best I can. But first, let’s work through a bit of background info so we’re all on the same page.
Battery Pack Basics
Today’s Li-ion battery packs are typically built using similar individual cells.
In a typical 18V or 20V Max battery pack, you have 2 rows of 5 cells, for 10 total. Each cell delivers 3.6V of power, which when multiplied by 5 equals 18V of nominal voltage. The 2 rows of cells are connected in parallel, to increase the charge capacity of a high capacity (Dewalt) or XC (Milwaukee) battery pack.
Compact battery packs have only a single row of 5 battery cells.
A typical high capacity battery pack can be described in terms of how many cells are in series, and how many sets of cells are in parallel.
A typical compact battery pack can be descried as having a 5S1P configuration (or simply 5S), and a typical high capacity or XC pack can be described as having a 5S2P configuration. 5×2 = 10 total cells.
Dewalt’s FlexVolt battery packs natively operate in 20V Max mode. Instead of 1 row of 5 cells as in compact battery packs, or 2 rows of 5 cells as in high capacity packs, FlexVolt battery packs have 3 rows of cells.
In this mode, the FlexVolt battery pack can be described as having a 5S3P configuration.
But there’s something special about Dewalt FlexVolt battery packs. When paired with certain tools, the internal contacts between battery cells are reconfigured, connected all of them in series.
4V Max (3.6V) x 15 = 60V Max (54V nominal).
Dewalt will be launching the FlexVolt product family with a 6.0Ah battery pack (20V Max mode). In 60V Max mode, it will have 2.0Ah capacity. In 120V Max mode, which requires 2 FlexVolt batteries, the capacity will also be 2.0Ah.
But Dewalt is also launching higher capacity battery packs in a few months, with 9.0Ah capacity in 20V Max mode, and 3.0Ah capacity in 60V Max mode.
The FlexVolt 9.0Ah battery pack will be slightly larger, because it will consist of slightly larger and more capable battery cells.
Milwaukee M18 High Demand
Milwaukee’s M18 9.0Ah High Demand battery pack can be described as a 5S3P battery pack.
With a third row of cells connected in parallel, a High Demand pack can deliver more power than an XC battery pack, and it should also run a little cooler.
Milwaukee on the Defense and Offense
Milwaukee took a defensive and offensive stance the day Dewalt announced their new FlexVolt battery pack and cordless power tools.
They peppered their social media accounts with talk of their M18 High Demand battery pack, and also launched a new webpage that compared the two technologies, of course in their favor.
I have noticed Milwaukee making some fresh efforts to get the word out about their M18 High Demand technology.
In a comparison, this is what they say about their High Demand battery:
- 15 cell power output
- Up to 50% more work per charge
- All M18 batteries work with all M18 tools
And this is what Milwaukee says about Dewalt’s FlexVolt tech:
- 15 cell power output
- Con: less work per charge
- Con: smaller system
- Con: 20V tools with 60V pack do not deliver 60V performance
- Con: 20V packs do not work with 60V tools
They use + and -, and I take the “minus” to mean “con.”
Let’s look at those cons. Less work per charge? True, if you consider the FlexVolt 6Ah pack and not the 9Ah pack that is coming soon.
Smaller system? True. But I’m sure more tools are coming.
As I’ll discuss more in a bit, while the FlexVolt system might be smaller, I think it will potentially benefit more users than Milwaukee’s M18 High Demand battery pack will.
20V tools with 60V packs do not deliver 60V performance? So what? You still get greater runtime. And when Dewalt’s 9Ah pack comes out, it might be superior to Milwaukee’s 9Ah pack, based in battery cell power potential.
That 20V Max packs don’t work with 60V Max tools is indeed a major downside to the FlexVolt platform.
But, Milwaukee’s M12 and M18 tools and batteries are not compatible, only sharing a couple of multi-voltage chargers between both product families. At least Dewalt’s FlexVolt batteries are one-way cross-compatible with 20V Max tools and chargers.
As you can tell, I’m not a fan of Milwaukee’s comparison – it seems unfair, at best.
Milwaukee: Voltage is only PART of the story…
This is Milwaukee’s motto when comparing their High Demand tech to Dewalt’s Flexvolt tech. And they’re right. They’re worried that professional tool users will focus on the numbers, that they will believe 60V Max is superior to M18, without truly understanding the differences.
Milwaukee’s comparison is of course carefully crafted to convinced you of their superiority.
Milwaukee compares their High Demand battery pack to the 6.0Ah Dewalt FlexVolt battery pack, completely ignoring – or hiding – the fact that Dewalt has a 9.0Ah pack in the works.
Milwaukee also describes their High Demand pack as THE WORLD’S FIRST & ONLY 18V HIGH DEMAND™ 9.0 BATTERY, but it’s NOT!
Neither brands’ 9.0Ah battery packs are out yet, and at this point it’s anyone’s game. I believe both have Fall 2016 ETAs. It’s quite possible that Dewalt will beat Milwaukee to market.
Milwaukee emphasizes that their pack is built using 3.0Ah cells, and Dewalt’s with 2.0Ah cells, but they don’t tell you that the 2.0Ah cells are on-paper better than their 3.0Ah cells.
But talk to them about battery pack technology, and they’ll tell you that the battery cells are only part of the picture, and that pack design, including how thermal energy is dissipated, can make a huge difference. They are absolutely right about this too.
I have not yet seen a Dewalt rebuttal, but I anticipate that we’ll see some fierce competition between the two brands in coming months.
Dewalt FlexVolt Advantages
First, higher voltage power tools are slightly more efficient. When you have fixed power capacity (voltage x current), a higher voltage and lower current motor will be a little more efficient than a lower voltage and higher current one.
With higher current comes greater energy losses, due to internal resistance and heat. Heat is a battery cell’s biggest enemy, which is why power tool brands go to great lengths to design packs that run as cool as possible.
Dewalt’s selection of 2.0Ah cells for their FlexVolt battery pack was deliberate. And the reason for this decision also explains the selection of larger 3.0Ah cells for their slightly physically larger higher performance FlexVolt battery pack that will shortly follow.
Going from 2.0Ah to 3.0Ah, in regard to the battery cell size most brands use in their 18V-class battery packs, results in a significant and disproportionate decrease in performance potential. The best 3.0Ah cells that I have seen cannot perform comparable to the best 2.0Ah or 2.5Ah cells than brands have put to use in recent years.
Because Dewalt selected high performing 2.0Ah cells, and larger 3.0Ah cells, they can squeeze a lot of current out of their FlexVolt battery packs.
So in 60V Max mode, you have high voltage and also reasonably high current delivery potential.
I thought I had a solid understanding of the Dewalt FlexVolt battery and the new cordless power tools, but they were kind enough to answer a few questions for me over the phone.
One of the more illuminating parts of the phone call was our discussion of the power ceiling of FlexVolt tools, and it was considerably higher than I had anticipated.
Quite frankly put, Dewalt FlexVolt tools and batteries perform at a level that surpasses what 18V-class tools are capable of.
An 18V-class tool can deliver less than a theoretical 1000 watts of power. So that would be around 56A for an 18V battery pack. That’s probably not sustainable, 1000W was more thrown out there as a theoretical ceiling.
But with FlexVolt, some of the higher performing tools are designed to deliver up to around 1700 watts of power.
I am not kidding. 1700 watts of power. And in case you think I heard wrong over the phone, look up the product specs for the upcoming FlexVolt grinder, model DCG414. It’s rated at 13A and is said to deliver 1700 unit watts out of power.
Okay, so let’s say it hits a power spike of 1700 watts. If you consider 60V Max, that’s 28.3A current draw, and 31.5A current draw if you consider 54V nominal.
28.3A is within the realm of what’s possible with 2.0Ah Li-ion cells, maybe slightly higher. 31.5A is a bit higher than the on-paper ratings I’ve seen for high performing cells, but good battery pack cooling can help make it realistic.
Milwaukee is NOT going to be able crank out that level of power from an M18 High Demand battery pack. If they used the same 2.0Ah cells, instead of the lower performing but higher capacity cells their High Demand packs are built with, they could match or exceed the same power draw.
But… at 1/3 the voltage you would then have 3x the current coursing through the battery pack, and through the tool. This would create some very difficult engineering considerations. Higher current draw would require thicker wires and heavier duty components.
The Dewalt engineer I spoke through wasn’t talking about Milwaukee specifically, but they said that if you tried to design 18V-class tools that compared with FlexVolt tools, the current and operating temperatures would be so high that contacts and connections might start melting.
That seems like it could be an exaggeration, but I do believe that you can squeeze more power out of a FlexVolt battery pack than an M18 High Demand battery pack. This would also be true with Dewalt’s upcoming 9.0Ah pack.
Milwaukee M18 High Demand Advantages
I also spoke with Milwaukee product managers and engineers to better understand the capabilities and potential limitations of their new 9.0Ah battery pack.
I mentioned my hesitation about High Demand battery pack performance, stemming from the on-paper specs I’ve seen for the best 18650-sized 3.0Ah Li-ion battery packs, and they convinced me otherwise. They made it clear that there High Demand battery packs can indeed deliver the performance needed to drive the next-generation of heavy duty cordless power tools.
On paper, a 5S2P battery built with 2.0Ah cells (or even 2.5Ah cells in certain conditions) should perform comparable with a 5S3P battery built with 3.0Ah cells. So what’s the point of a 9.0Ah battery pack that’s larger and pricier? Right?
But no, on paper specs are thrown out the window in the context of a battery pack. Okay, maybe they’re not thrown out the window, but there’s much more to a battery pack design than on-paper current specs.
I recall a demo I observed at the Milwaukee 2015 media event. There were 2 M18 Super Hawg drills connected to test equipment. One was being powered by a 5.0Ah battery pack, and the other by a 9.0ah High Demand battery pack.
The power draw of the Super Hawg was so high that it eventually triggered the over-current protection on the drill powered by the XC battery, while the HD battery-powered tool kept going.
So, clearly, there’s something to Milwaukee’s M18 HD battery packs.
Imagine what they could have done if they moved to a larger form factor battery pack, similar to what several other brands have done or are doing soon. But, let’s not forget that the HD battery pack is already a larger form factor, it’s a 5S3P pack, when all other brands – excluding Dewalt – only have 5S2P packs.
Milwaukee seems to have designed their 9.0Ah High Demand battery pack without knowing about Dewalt’s FlexVolt plans, and based on my discussion with a Dewalt Product Manager about how long it took to develop the FlexVolt battery pack and tools, it seems that Dewalt started work on their battery platform before Milwaukee’s HD plans were publicly known.
Milwaukee’s M18 High Demand battery pack, and their new tools designed to take advantage of it, there is one clear advantage – complete (or near complete) backwards compatibility.
Except where there might be a physical limitation, Milwaukee’s M18 HD 9.0Ah battery pack should fit any M18 cordless power tool, charger, or accessory. That’s a big deal. Who looks forward to working with and maintaining tools and batteries from 2 or more cordless power tool lineups?
Dewalt’s FlexVolt battery packs are compatible with their 20V Max tool, chargers, and accessories, but the reverse is not true. You cannot use 20V Max batteries in FlexVolt tools or accessories.
Meanwhile, any M18 battery should fit any M18 tool.
Some of Milwaukee’s M18 tools might experience an “HD effect,” similar to their “XC effect,” where certain tools benefit from being powered with an XC battery pack instead of a compact battery pack. Users might also see a difference when running heavy duty tools in high demand applications.
So Which is Better, Dewalt FlexVolt or Milwaukee M18 High Demand?
From an objective standpoint, weighing everything together, I would say that Dewalt FlexVolt is superior to Milwaukee M18 High Demand.
But, that’s in terms of potential. I believe that Dewalt has the potential to push FlexVolt batteries to greater limits, and that it’s a more future-proof technology.
From what I’ve seen, Milwaukee’s M18 High Demand tech is most advantageous when it comes with heavy duty tools, such as Super Hawgs, large rotary hammers, and tools like that.
Dewalt’s FlexVolt tools seem to be more designed to give you cordless power tools with corded-like performance, features, and capacity.
It can be argued that many of Milwaukee’s M18 Fuel brushless cordless power tools were designed to do the same, and they have certainly made good on that promise.
Milwaukee’s M18 High Demand battery pack might be more appealing for certain users, such as those who have heavy duty needs and who don’t want to mess around with multiple tool platforms.
You’re not going to want to pair certain Dewalt 20V Max tools with a FlexVolt battery pack, such as when a compact pack would work just fine. An impact driver with a FlexVolt battery pack? No, I’d rather than an impact with a compact pack, or maybe a high capacity pack at the most.
Milwaukee has a greater selection of M18 brushless tools. Dewalt’s FlexVolt launch includes a brushless circular saw and a brushless reciprocating saw, but if you want to use 20V Max tools, you’re most likely going to have to work with the 2 separate voltages. You could have one set of chargers, but for the best user experience, you’re going to want separate 20V Max and FlexVolt tools and batteries.
I think that Milwaukee’s M18 High Demand technology is highly appealing, and there are definitely some benefits for users. But those benefits target certain users with heavy demands.
Dewalt’s FlexVolt tech offers corded-like performance and features, and potentially benefits many more users. Yes, the new battery and tools seem to be designed in part as solutions for those with heavy duty tool needs. But you get more than that.
When trying to decide whether either of the FlexVolt or M18 High Demand technologies were better than the other, it came down to one question: which holds more potential for me? And the answer to that is Dewalt FlexVolt.
If I want more runtime, I can buy more batteries. I have yet to across an application where I used a Milwaukee M18 tool and overtaxed its battery pack. But I have come across applications where there’s no M18 tool for the job.
With FlexVolt, Dewalt is introducing a cordless table saw, 12″ miter saws, some heavy duty brushless saws, and some other heavy duty tools. What’s next, a 10-inch miter saw? 10-inch cordless table saw?
If you take 10 pro tool users – contractors, electricians, plumbers, remodelers, enthusiasts, and advanced DIYers, how many would potentially benefit from Dewalt’s new FlexVolt tools and batteries? How many would benefit from Milwaukee’s M18 High Demand tools and batteries? Exactly. I think you’ll see more people interested in Dewalt FlexVolt than Milwaukee M18 High Demand.
Milwaukee is coming out with new tools, such as their 10-inch sliding miter saw, and already has a very impressive stable of M18 Fuel brushless power tools.
The new M18 sliding miter saw – does it require an HD battery? No, it can be powered by an M18 XC battery just the same, except perhaps in very heavy duty applications.
If You’ve Made it This Far
Hopefully you understand the Dewalt FlexVolt and Milwaukee M18 High Demand systems as well as I believe I do.
The question of whether one is better than the other is difficult to answer, and it gets even messier if you think about Dewalt vs. Milwaukee in a broader sense.
In terms of Dewalt vs. Milwaukee cordless lines, both brands have distinct advantages. Dewalt has been introducing more trade-specific tools, and with FlexVolt I believe they’re taking the upper hand in regard to core tools. Milwaukee has a stronger range of trade-specific tools, and will soon turn their attention to remodeling tools.
Dewalt 20V Max plus FlexVolt, vs. Milwaukee M18? We’ll get back to that another time.
But if we’re just talking about FlexVolt vs. M18 High Demand, I’d say that Dewalt holds the advantage. Do you agree? Disagree?
The next question to ask is about how Dewalt FlexVolt tools compare to Milwaukee M18 Fuel brushless tools, at least where comparisons are possible. Power? Runtime? The FlexVolt vs. M18 High Demand debate isn’t over – it’s just begun.