MAX, PowerStack, PowerPack, FLEXVOLT: Which DeWalt battery is right for you? DeWalt currently offers three PowerStack (PS) batteries: the 1.7 Amp hour, 3.5 Ah, and 5 Ah. In this article, we’ll compare them to the MAX, PowerPack, and FLEXVOLT batteries.
The main selling point of PowerStack batteries is DeWalt’s claim that they deliver 50% more power, provide 50% more work per charge, and offer more recharges than 20V MAX equivalents.
Runtime
In our video review, the 5 Ah PS and 5 Ah MAX had the same runtime on a shop vac. However, after running two more vac tests we found the 5 Ah MAX ran 2-4 minutes longer. So, I’d bet on the MAX battery keeping the lights on longer.
50% More Power
DeWalt says both the 3.5 Ah and 5 Ah PowerStack batteries deliver 50% more power than a 5 Ah MAX battery.
As I understand it, compared to MAX batteries, PowerStacks lose less energy as heat, allowing more energy to be used for work.
In our testing (see video below), the 3.5 Ah and 5 Ah PowerStacks ran faster than the 5 Ah MAX. It’s a clear difference you can feel. But, the 3.5 did not run cooler.
50% more work per charge
In our video review, we saw the 5 Ah PS cut 78 feet of 2x lumber compared to the 5 Ah MAX’s 56 feet. That’s not quite the ‘50% more work per charge’ claimed in DeWalt’s original marketing, but it’s still impressive. The 5 Ah PS also ran much cooler.
The 3.5 Ah PS cut 45 feet of 2x lumber, compared to the 5 Ah MAX’s 53 feet. So, the 3.5 performed about 80% of the MAX’s work.
Longer Lifespan
DeWalt originally marketed the PS as having twice the lifespan of the MAX. They’ve adjusted that on their site to ‘longer lifespan,’ which could mean a couple of different things.
It could mean that, for example, if a 5 Ah MAX drops to 80% of its original charge capacity after 300 recharges—which is roughly my experience—then a 5 Ah PS should retain about 80% at 600 recharges.
Or maybe they mean that if the MAX recharges until it drops to, say, 60% of its original capacity before it won’t recharge anymore, the PS batteries recharge down to 30%.
All I know for sure is that full charge bars in year one don’t deliver the same runtime as full bars in year three. I also know heat is the enemy of runtime and probably reduces rechargeable lifespan.
The 1.7
The 1.7 Ah PowerStack was the first PS model released, and we saw many reviews showing it outperforming DeWalt’s massive 15 Ah FlexVolt battery in screw-drilling tests. In our testing, however, while the 1.7 Ah was impressive, it ran slower than the 9 Ah FlexVolt.
The 1.7 Ah PS also ran hotter than any battery we’ve tested so far. If running cool is a key factor in DeWalt’s claim that PowerStack batteries last longer than MAX batteries, this isn’t a good sign for the 1.7 Ah.
FYI: The 6 and 15 Ah Flexvolt batteries use 18650 cells, whereas the 9 and 12 Ah Flexvolts run 21700 cells. However, it’s not all about the cells. For example, DeWalt’s 4 Ah compact battery uses 21700 cells but runs slower than the 5 Ah MAX, which uses 18650 cells.
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3.5 Ah PowerStack
5 Ah PowerStack
5 Ah MAX
Bottom Line
For small 20V tools like wrenches, I think the 1.7 Ah PowerStack is a good fit. For more power and work capacity the 5 Ah PS seems like the best bet if you can find them on sale and don’t mind the larger footprint.
With the 3.5 Ah, I ask myself: if it and the 5 Ah MAX were the same price, would I trade 15% more work capacity for more power in a smaller package, given the 3.5 does not run cooler than the MAX? Maybe, if they cost the same.
Let us know your thoughts in the comments and check out this review to see these bad boys in action. See ya!
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