20V Max or 18V battery, which one is more powerful?
"When I switch from an 18V system to a 20V system there is a huge difference in power." Ah, if only I had a quarter every time I heard that…
No matter how many times I step into someone's conversation and explain it to them, the 18V vs. 20V Max debate will continue. Now let me take the talk out of the drama: they're the same. We assure you.
I'd like to stop there, but people will insist that a 20V Max system is more powerful than an 18V because 20 is bigger than 18. *sigh*
Internal 18V and 20V
Seriously though, I love talking about this stuff, so let's get started. In the US, manufacturers such as Bosch, Milwaukee, Ridgid, Ryobi, and Makita all operate on 18V battery platforms. DeWalt and Porter-Cable run on their 20V Max systems. All it takes is a voltmeter to provide some quantifiable data, and a look inside the battery will tell why.
20V Max has same battery as 18V battery
Inside the battery pack are individual battery cells. In 18V/20V Max systems, they are always set in series of 5. Then connect each group of 5 in parallel to increase the amp-hours and overall battery capacity (measured in watt-hours). For more information, check out our feature on Voltage vs. Amp Hours.
Each of these batteries has two voltage ratings – a nominal voltage and a maximum voltage. When a battery is fully charged, it produces a higher voltage than when it starts to discharge, even slightly higher. It's actually a chemical property of the lithium-ion system. Each cell has a nominal voltage of 3.6 volts and a maximum voltage of just over 4 volts.
- 3.6 volts (nominal) x 5 cells = 18 volts
- 4 volts (maximum) x 5 batteries = 20 volts
That's it. That's all the difference between 18V and 20V Max batteries. It's just a matter of whether the company uses the nominal voltage or the maximum voltage as the rating.
20V vs. 18V is really about marketing
This raises several interesting topics. First, many European countries are stricter about how companies advertise. You'll find that in most areas, tools are sold at their nominal voltage. That means 18V high power tools and 10.8 volt tools. From a marketing standpoint, being able to put higher numbers on a tool will make it seem more powerful. Applying a nominal voltage across it indicates where the battery will operate most of the time.
For some reason, the 20V Max vs. 18V debate seems to be just one of those 5 battery pack platforms. Everyone is advertising their 12V series (3 cells), not their 10.8V series. Jumping to OPE (Outdoor Power Equipment), we get 40V systems (10 cells) that are replacing the 36V platforms of a few years ago. So before you develop a bad taste in DeWalt or Craftsman power tools, know that everyone does it somewhere.
20V MAX is the same as 18V nominal – Proven by DeWalt
The crux of the whole debate may just be to go to the DeWalt 20V MAX* website and look for the asterisk. On the DeWalt 20V Max page, you'll see an asterisk next to each 20V MAX* instance, and near the bottom the following:
On DeWalt and Craftsman tools, you'll notice 20V MAX* on their packaging. The asterisk and the word "MAX" point to a document that clearly states that the voltage rating is the maximum value. Is this a marketing ploy? Yes. Is it misleading? Unless you don't seek explanations when you see something marked with an asterisk.
- Barry Bonds, single-season home run king* – known to have used performance-enhancing drugs
- Double Chocolate Fudge Brownies, bake 25 minutes* – 18 minutes at high altitude
- 20V MAX* – 20V initial maximum measured at no load, 18V nominal
in conclusion
So yes, 18V and 20V MAX systems run on the same voltage. Let me say it again: an 18V battery and a 20V MAX battery produce the exact same voltage.
Still, the internals of each cell do vary from brand to brand — even within the same brand. Technology and chemistry are constantly advancing. So are the DeWalt 20V MAX cords more powerful than their original 18V cords? Yes. Absolutely. Because the electronics, motors and batteries are better. However, they still provide the exact same voltage as 18V tools.
If you don't take our word for it, take DeWalt's word for it!