It’s an age-old question: “Do I buy a 12 volt rechargeable battery-powered tool, or do I step up and buy an 18V (or bigger) one?

That’s a great question and one we’ve asked ourselves.

There are lots or pros and cons. Each will have an effect upon the tools you select. But there are also some definite surprises!

(Image/Wayne Scraba)

Generally speaking, 18V and larger tool batteries will deliver more power than 12V batteries, but a key to performance is actually the amp-hour rating of the specific batteries.

The capacity of an electric tool battery is measured in amp-hours (Ah).

Obviously, this refers to how many amps the battery can deliver in an hour. Using a Milwaukee M12 Redlithium battery as the example, it has a capacity of 2.0 amp-hours. If you multiply the amp-hour rating by the voltage, you arrive at the “power” capability. This is the amount of energy consumed by the device and it can give an answer as to the amount of work a battery can provide on a single charge.

That’s not the end of it though.

Milwaukee Tool offers an extended capacity M12 Redlithium battery. It has double the amp-hour rating of the base battery (above), and they have recently released an M12 Redlithium High Output battery. It will offer a full 5.0 Ah capacity.

In contrast, a standard 18V M18 Redlithium battery from Milwaukee also provides 2.0 amp-hours of capacity, but keep in mind to arrive at the power capability, you’d multiply the Ah by 18 (in comparison to 12). As a result, it still offers more ultimate power than a standard 12V battery, but not as much as a 4.0 Ah 12V Redlithium power tool.

Fair enough. But typically, the higher the power, the heavier and larger the tool. There are some exceptions though: I have a several air powered impact wrenches in both 3/8 and 1/2 inch size.

I’m certainly not going to replace them with battery powered tools. But for quick little jobs, it’s really difficult to beat something like Milwaukee’s M12 Fuel 1/4 inch impact driver—I just have to remember to keep the batteries charged! It’s a brushless tool and it’s positively tiny in terms of size. It measures about five inches long, eight inches tall, and weighs just under two points. It has a maximum torque figure of 1,300 inch-pounds.

Compare the M12 tool to the new upcoming M18 Fuel option. It’s about 5.5 inches long, about 7.5 inches tall, and weighs about 2.25 pounds. The maximum torque figure here is 2,000 inch-pounds. Keep in mind 12V batteries tend to be a bit lighter than their 18V counterparts, but in general bigger in capacity doesn’t always equate to bigger in size.

When it comes to cost, at the time of this article, a 1/2 inch M12 Fuel brushless driver drill (part number MWT-3403-20) has a price of $139. Meanwhile, a similar M18 Compact 1/2 inch driver drill (part number MWT-2606-20) actually comes in less costly at $119.

That’s not really a trend, but it’s always a good idea to be careful when it comes to price comparisons.

What you should do though, is to try to stick with one brand.

That will likely make it easier to interchange batteries. Now this doesn’t always mean you can swap batteries from tool-to-tool, but some companies (again, using Milwaukee as the example) offer chargers that can charge both 12 and 18 volt batteries, which can really de-clutter your workspace.

In the end, it’s a matter of personal choice. You have to decide what you want the tool to do.

Generally speaking, the higher output (battery) tools will be a bit bulkier and perhaps a wee bit heavier with the battery installed. In most cases, the higher output batteries provide a bit longer run time. Cost difference between the respective tools can prove negligible. For a closer look, check out photos:

As noted above, I have a good cross section of air tools in my collection and I really don’t have a big need for something like a 1/2 inch or even a 3/8 inch drive battery-powered impact. But these compact M12 Fuel tools from Milwaukee Tool are really handy for tight quarters and light duty jobs. (Image/Wayne Scraba)
In hand, this M12 Fuel 1/4 inch impact driver takes up little or no space, particularly when fitted with a small 2.0 amp battery. (Image/Wayne Scraba)
As you’d expect, different size batteries provide different levels of power. You can see the difference here between a 2.0 amp and 4.0 amp Milwaukee tool battery pack. The article offers some insight into battery sizing and ultimate power levels. (Image//Wayne Scraba)
Even more powerful is this X6 M12 Redlithium battery. It delivers up to three times more run-time, 20 percent more power, and twice as many recharges than a standard lithium-ion battery. You can find them under part number MWT-48-11-2460. (Image/Summit Racing)
As pointed out in the article, there are a number of cases where a higher power tool such as this M18 Fuel brushless impact is almost as compact as the lower power M12 option. This M18 Fuel impact from Milwaukee Tool (MWT-2857-20) features a wrench torque output of 2,000 inch-pounds. That’s a bunch. (Image/Summit Racing)
That same tool is also available in a complete kit (part number MWT-2853-22). The kit includes the impact driver, a battery charger, a pair of 18 volt 5.0 amp extended capacity batteries, and a carrying case. (Image/Summit Racing)
If you need big grunt for your 18V Milwaukee rechargeable tool, these high output XC8.0 Redlithium batteries (part number MWT-48-11-1880) provide 50 percent more power and run 50 percent cooler when compared to a standard M18 Redlithium XC battery pack. Where this big eight amp power really shines is when the temperature drops. (Image/Summit Racing)
Of course, battery powered impact tools aren’t the only ones you can get. Case-in-point is this diminutive M12 Fuel cordless drill I regularly use for close work. While it doesn’t pack the punch of some larger examples, it’s definitely handy. (Image/Wayne Scraba)
Speaking of handy, on my wish list is this 3/8 inch drive, right angle cordless M12 Fuel drill/driver from Milwaukee Tool (part number MWT-2415-20). It’s compact and light plus it accepts the same battery packs as my other M12 Fuel tools. (Image/Summit Racing)

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Author: Wayne Scraba

Wayne Scraba is a diehard car guy and regular contributor to OnAllCylinders. He’s owned his own speed shop, built race cars, street rods, and custom motorcycles, and restored muscle cars. He’s authored five how-to books and written over 4,500 tech articles that have appeared in sixty different high performance automotive, motorcycle and aviation magazines worldwide.