I was looking at battery power tools and their different battery voltages. Some of the voltages are listed twice, with and without "max". An example for mowers is "40-volt" and "40-volt max". What's the difference between the voltages with "max" and without "max"?

battery voltages

  • What brands are you looking at it may have something to do with the style of the battery contacts , I have a 6 ah battery that the contacts look the same as the 2 ah batteries the difference is each cell is larger.
    – Ed Beal
    Jul 29, 2020 at 17:22
  • What website is this? Most likely those categories are just echoing the text in the advertising blurbs for the products found. It's possible, tho' a bit unlikely that, e.g., a "40 V max" tool would function with a 24-V battery, but my guess is just poor English. Jul 29, 2020 at 17:45
  • @CarlWitthoft Lowes.
    – Ghostship
    Jul 29, 2020 at 18:04
  • This isn't a question about batteries. This is a question about a website's search engine. There are a variety of reasons to allow ranges in search filters. Jul 29, 2020 at 18:42
  • @Harper-ReinstateMonica not sure I agree with you. I pulled up the Lowes site and "20 volt max" yields a set of 7 brands, while the "20 volt" yields a different set of 7 brands. "Max" is all about marketing 'cause "Max" sounds... maxier...
    – FreeMan
    Jul 29, 2020 at 19:26

1 Answer 1


There is one brand of "20-volt Max" tools that reasonably clearly state on their packaging something to the effect of:

Battery provides 20 volt maximum starting power. Provides 18-volts in use.

As a matter of fact, they'll sell you a simple physical adapter (and some wiring between the contacts) that will allow you to use the "20-volt max" batteries on their older 18-volt line of tools.


"Max" is 98.475% marketing because "Max" sounds, well, like more than "not-max". (And 99.238% of all statistics on the internet are made up on the spot.)

  • Presumably that "20 V starting" is the rating of their battery, not the tool's draw. Jul 29, 2020 at 17:46
  • 1
    Yes it is, @CarlWitthoft. I don't remember the exact wording at the moment and can't be bothered to go look at the DeWa... (oops) site right now to get it. :)
    – FreeMan
    Jul 29, 2020 at 17:47
  • Edited to make it more explicit
    – FreeMan
    Jul 29, 2020 at 17:47
  • 1
    Most assuredly, @GeorgeAnderson
    – FreeMan
    Jul 29, 2020 at 19:12
  • 3
    The "20V" claim is entirely bogus. Li-Ion batteries have a cell voltage of 3.6V nominal which divides evenly into 18V (i.e. 5) but not into 20. So there is no way to get 20V out of a 5S battery pack which these "Max" cells are. It's marketing hype!
    – jwh20
    Jul 29, 2020 at 19:30

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.