As you might know, the difference between Dewalt 20V Max and 18V is essentially marketing in nature, rather than relating to electrical power. There is no functional difference between 20V Max and 18V!
18V is the nominal voltage for 5x 3.6V Li-ion batteries connected in series. 20V Max takes into account 5x 4.0V, which is the average maximum voltage at full charge with no load applied.
In other words, if you have a Dewalt 20V Max 5Ah battery from the USA and a Dewalt 18V XR 5Ah battery from Europe, they are – for all intents and purposes – the same exact battery but with different labels.
Cover the labels, and you shouldn’t be able to tell the batteries apart.
If there’s no difference where did “20V Max” come from, and why?
More than 11.5 years ago, back in June 2011, Dewalt announced their then-new 20V Max cordless power tool system.
At the time, Dewalt said there were still 63 million 18V stem-style batteries still in the field, and that they would continue to support the 18V platform for a long time. (10 years later, in September 2021, Dewalt finally discontinued their 18V cordless power tool system.)
Dewalt marketing representatives emphasized that, in order to avoid confusing customers and tool users, “20V Max” would create distinction between their 18V primarily NiCad-based cordless power tool system, and the modern line centered on the new slide-style battery
“20V Max” comes from the maximum off-the-charger voltage, with 18V being the battery packs’ nominal voltage.
One year earlier, in June 2010, Dewalt launched their 12V Max cordless power tool system. Dewalt was not the first brand to use such nomenclature.
Bosch switched over from 10.8V to 12V Max starting in mid-2008, with their second generation PS20 cordless Pocket Driver.
From a Bosch July 2008 press release:
The new [12V Max] terminology, which replaces 10.8V, is meant to reduce confusion in the marketplace by clearly identifying tools that are rated at maximum voltage (i.e. 12V) rather than nominal voltage (i.e. 10.8V) by using the “Max” designator.
Makita launched their first 12V Max cordless power tools in late 2010, converting over from 10.8V as Bosch had done.
From Makita’s November 2010 press release:
The change to “12V max” is consistent with lithium-ion battery voltage ratings that have been adopted in the marketplace since Makita first launched 10.8V Lithium-Ion products in 2008.
Here’s a summary in chronological order
2006 May: Bosch announced 10.8V PS20 Pocket Driver
2007 October: Milwaukee announced a “12-Volt Sub-Compact driver” (2401-22)
2008 July: Bosch switches to 12V Max terminology
2008 July: Makita announces first 10.8V tools
2008 October: Milwaukee announced M12 Hackzall (2420-22)
2010 June: Dewalt announces 12V Max cordless power tool system
2010 November: Makita switches to 12V Max terminology
2011 June: Dewalt announces 20V Max cordless power tool system
With 12V Max already adopted in the USA by Bosch, Makita, and Dewalt, the plan for Dewalt to go with 20V Max for their new 18V-class Li-ion cordless system made perfect sense.
However, “20V Max” was only in use in North America. In Europe and elsewhere, the new cordless lineup was given “18V XR” branding.
I should add that Dewalt eventually brought the XR – extreme runtime – branding to the USA to describe their premium 20V Max brushless cordless power tools and higher capacity batteries.
The popular opinion is that “20V Max” sounds better than 18V, where consumers might perceive 20V Max as delivering higher voltage or more power than 18V. It is also widely believed that “Max” branding is not widely used outside of North America due to other regions’ advertising and consumer protection regulations.
In recent years, some brands have eliminated the “Max” part of their cordless system branding. For instance, Bosch has renamed their compact cordless power tools as simply “12V” in Europe. Bosch still uses 12V Max in the USA.
Whether Dewalt “20V Max” was created for market distinction, user perception, or other reasons, it was in line with emerging standards.
Today, there are 12V Max, 20V Max, 24V Max, 40V Max, 60V Max, 80V Max, 120V Max, and other such cordless power tool systems.
18V still remains popular, although mainly with legacy systems. New cordless systems tend to be given “Max” voltage branding.
For example, Makita uses 18V to describe their core cordless system, and went with 40V Max to describe their new XGT cordless system.
Some brands, such as Dewalt, tend to be explicit and clear, requiring nominal voltage disclosures in all marketing materials. Others, such as Harbor Freight’s Hercules and Bauer brands, simply describe their cordless systems as 12V or 20V.
Most users should be accustomed to this by now.
I have found there to be far less confusion between 12V Max and 10.8V, or 20V Max and 18V than in earlier years.
However, occasional comments and questions, such as a recent reader statement that said “US batteries give you 2 more volts” make it clear that there is still some confusion or misunderstanding.
I have posted about Dewalt 20V Max vs. 18V twice before:
This seems like one of those questions that needs to be revisited every couple of years.