Cutting the cord is easy. Choosing a cordless battery platform, however can be much more difficult. From 12-volt to 18-volt and prosumer to professional, here's a handy guide for selecting the battery platform that's right for you.
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Let's start by narrowing down the battery voltage categories. We will ignore the 14.4V, 24V and 36V battery platforms. The 14.4V is on the way out, as there's not much need for an in-between size with current 12V being so powerful. The 24V and 36V batteries only power professional grade tools with limited opportunities to expand beyond those tools.
That leaves us with 12V and 18V battery platforms which are the most popular and widely available cordless tools. Don't be scared off by 18V and 19.2V tools as being less powerful than the 20V tools. 20V is a marketing term, as the manufacturers who use it are listing the maximum voltage (with no load) instead of the nominal voltage of 18V. This DeWalt 20V MAX is a good example -- note the asterisk and read the fine print.
We can limit the battery selection even further by removing nickel-cadmium (NiCd), nickel-metal hydride (NiMH) batteries from the list and focus on lithium-ion (Li-ion). Unless you are looking for something cheap, lithium-ion batteries make the most sense as they are lighter and offer more runtime. Nickel battery powered tools are becoming more scarce, and the last thing you want to do when investing in a cordless tool platform is limit your options.
Choose Voltage Based On Your Job
Pro users make a living with their tools and can't afford to have them break on the job, which is why they pay a premium for better tool construction and battery technology.
Everyone else is a DIYer, whether your skill is zero or very advanced. A 12V tool will fit the needs of most handy types who can install a screen door or put up hooks in the garage. 12 volts won't drive many deck screws but they are small and lightweight enough for most users to handle. 12V batteries have the most expandable options, as they can be used in vacuums, lights, radios and heated gear, as well as drills, circular saws and impact drivers.
Weekend warriors who plan on building sheds or cutting sheets of plywood, though, will need to step up to 18V power. If it's just a few weekends per year, you can save money by going corded for bigger jobs. No need to spend the money on an 18V tool that sits on the charger most of the time. If you can handle the heft and the cost, 18V tools give you the most flexibility as they can handle all of the smaller jobs with ease but can also be used to power recip saws, hammer drills and grinders.
Stick To One Manufacturer And Battery Type
Invest in a tool platform that you can afford to expand on. Don't blow everything on one tool that is so expensive you have to switch manufacturers to round out your tool collection. Cordless power tool batteries are not cross compatible among manufacturers. If you go Craftsman then you are stuck with them unless you start over with another company.
If you've already got a cadre of NiCd tools, it makes the most sense to stick with that manufacturer if their chargers are backwards compatible and can charge both NiCd and lithium-ion. Bosch has taken battery technology a step further with their wireless charging systems, while remaining backward compatible with their current lithium-ion lineup.
Premium tool companies sell their tools sans battery so you can just expand on the tools without paying for expensive batteries each time.
The highest rated tools aren't always the best fit. Go to a hardware store and get your hands on as many power tools as you can. Twist them with your wrist, squeeze the grip and handle it as you would if you were using it. Take note of the tools balance, weight (with a battery in it), trigger pull and other features such as belt clips, LED placement and battery style (flat bottom so the tool stands upright or cartridge style that requires the tool lay on its side).
Comfort trumps almost everything. If a tool is awkward to use, then it will sit.