Cordless Tool Realities

Five new benefits delivered by today’s best technology

Article and photos by Steve Maxwell

A handful of performance benefits have advanced the world of cordless tools, but the fact that most tool users don’t know it yet could be a good thing for you. Even though today’s best models don’t look much different, they deliver significant competitive advantages over the average. This translates into more work done each day for those smart enough to jump on this fast train early. If you build for money, this means greater profits as you compete against builders who are slower and more poorly equipped. If you build for yourself, it means you get more done after dinner and on weekends. The best way to understand the benefits is to experience them for yourself. When you finally do, here’s what you’ll discover.


Benefit #1: Fewer Trips to the Charger

Leading-edge battery run time has lengthened to the point where it’s downright surprising. You can drive deck screws all morning long with a high-capacity battery and never walk to the charger until break. Something called amp-hours measures how much energy a battery pack holds, and you need to understand how this works and what to look for.

Today’s smallest capacity 18-volt batteries, for instance, are typically rated at 1.5 or 2.0 amp-hours. Top of the line batteries used to max out at 3.0 amp-hour, but 4.0 amp-hour batteries are becoming mainstream now. Manufacturers don’t always announce amp-hour ratings boldly on product packaging, so prepare yourself to look closely and ask questions before you buy. Dollar-for-dollar you’ll get more work out of a high capacity battery over it’s working life than you will with two lower capacity ones.

The move to lithium-ion battery chemistry began the advance that’s put more energy into smaller and lighter packs, but run time has been further enhanced by smart charging technology and more efficient energy conversion within tools, too.

The ability to deliver longer tool run times usually means more powerful tools. The reason has to do with tool voltage under load versus nameplate voltage. If you ever have a chance to put a voltmeter onto the terminals of, say, an 18-volt battery, don’t be surprised if it reads more than 20 volts. That’s normal because most stated voltage numbers are measured under some arbitrary load. In practice, however, battery voltage varies quite a bit. In my field measurements of battery voltage under load I’ve found that a fully-charged, 18-volt nicad battery in good condition can register as low as 15.5 volts during heavy use. Lithium-ion 18-volt batteries, by contrast, hold up much better when the going gets tough, managing to put out 17 or 18 volts.

As a tool user you’ll experience higher voltage as higher power, and quite a marked difference it is, too. In practice the ability for a battery to deliver longer working life usually comes hand-in-hand with the ability to maintain a higher voltage under load and for longer periods of time.


Benefit #2: Longer Lasting Motors

Brushless motor technology is beginning to show up in high-end cordless tools and it’s a good thing because it simplifies design so much and boosts working life. Brushless design eliminates the collection of springs and rubbing mechanical parts found inside most cordless tool motors on the market right now, replacing them with electronic, non-contact, non-moving equivalents. With no internal brushes involved, brushless motors gain in two ways. First, they convert more electrical energy into movement. There are no brush sparks and no rubbing, both of which waste power.

Milwaukee was the first mainstream tool company to bring brushless motors to cordless tools, and their system adjusts itself internally to deliver magnetic fields that change depending on the speed and load of the tool. It’s sort of like variable spark timing in a gas engine. The result is noticeably more work delivered from a given battery pack.

At least as important is the fact that brushless motors last longer than brushed equivalents because there’s no internal brush wear. In tests, I’ve seen brushless drills bore almost half a million 1-inch holes in construction lumber, while the same quality of brushed drill managed less than 90 per cent of that before wearing out.


Benefit #3: Powerful Pouch-Sized Tools

Manufacturers first brought lithium-ion batteries to cordless tools in 2005, and they were quick to use the new technology to transform large, previously-corded tools into equally-large cordless counterparts. Trouble is, tool users weren’t interested in spending the extra money just to get rid of a cord. There needed to be a more compelling advantage. This is exactly where tool users themselves became the driving force towards smaller, lighter weight cordless models.

We’ve come to expect that battery voltage is a good yardstick for tool power because that’s been the case ever since cordless tools first came out in the early 1980s. But the fact is, today’s best 18-volt drill is much more powerful than 18-volt models of the past, and significantly more powerful than average models today. This effect is especially noticeable with the brand new 12-volt brushless tools.

If you’re been building for more than 20 years, you’ll remember 12-volt tools as just another short-lived stepping stone as manufacturers played one-upsmanship with each other, raising the ante from 7.2 to 9.6 to 12, 14.4, 18 volts and beyond. So if 12-volt tools weren’t anything special a few years after they came out in 1992, why would anyone want them now? That’s because not all 12-volt tools are created equal. Far from it.

When you couple a 12-volt lithium-ion battery with a high-end brushless motor you cross a threshold of performance that’s significant. Milwaukee is the only company that offer this combination right now, and their M12 FUEL drill and impact driver are small enough to fit into your tool pouch yet powerful enough to drive most sizes of deck screws. This is especially handy when you’re climbing around on a roof frame putting up trusses or working on a ladder. Sub-compact, brushless 12-volt tools like these are so small that you’ll even have room in your pouch for a spare battery.


Benefit #4: Longer-Lived Batteries

Short working life and expensive battery replacement costs are the biggest complaints most users have against cordless tools, and these complaints are completely legitimate based on past performance. For too many years some batteries have lost the ability to hold a charge sooner than they should have. And if that wasn’t bad enough, it’s not unusual to have to pay more for a pair of replacement batteries than the price of a new drill with charger and two new batteries.

The service life of today’s best new batteries is longer than ever and manufacturers are willing to put their warranties where their advertising claims are. For instance, Ridgid offers a lifetime warranty on batteries for registered tool owners. You’ll never need to buy a replacement battery again. Milwaukee extends two and three year battery coverage for professional users and Ryobi gives three years of protection. Why have things improved? There are technical reasons.

All else being equal, lithium-ion batteries are tougher than traditional nickel cadmium equivalents, especially under Canadian conditions. Charging and discharging nicad batteries when they’re cold, for instance, greatly shortens life, while performance of the best li-ion batteries is almost unaffected by temperature. I’ve pulled them out of the freezer and run tests to prove it. Another reason top batteries last longer these days is because the electronics that charge and discharge them are much smarter.


Benefit #5: Smart Electrics

Grabbing a tool and heading off to work, then finding that the battery’s almost dead is a pain. Burning out a cordless drill because you’ve worked it too hard is stupid and wasteful. Ruining a battery because you keep it on the charger all the time between uses is infuriating because it shouldn’t happen. Eliminating all these problems is what smart cordless tool electrics do.

Need to know the state of charge of a battery before you climb all the way up that ladder? Just push a button on the battery and check the ‘gas gauge’. Is your over-enthusiasm for work making your drill heat up too much? Smart cordless circuitry shuts the tool down before you burn out windings and battery cells. Got a jobsite with multiple workers using cordless? Keep everyone powered up with a multi-station charger. The best can hold six batteries at once.

If you build and renovate you probably already own cordless tools. Who doesn’t? What’s not so obvious is how upgrading to a leading-edge systems offers advantages that go beyond the money you’ll save nursing your old cordless along. Figure out how much it really costs you to run back and forth to the charger every 15 minutes and you might just find that your old cordless is actually pretty expensive to keep.