Lightweight and powerful, lithium-ion (Li-ion) batteries have found their way into a vast array of everyday consumer products, ranging from cell phones to laptop computers. It should then come as no surprise that many of the biggest brands in power tools—Milwaukee, Makita, DeWalt and Ryobi—are increasingly incorporating the technology into their cordless drills, circular saws and reciprocating saws. Tools powered with Li-ion batteries offer several benefits. For starters, the batteries have a higher energy density than other battery types. That means tool manufacturers can either pack more power into the same size package or pack the same power into a smaller package. End result: An 18-volt Li-ion battery weighs roughly the same as a 12-volt nickel-cadmium (NiCd) battery. In addition, Li-ion batteries perform more work per charge with no power fade, have more charges per cycle, last two to four times longer than NiCd batteries and have longer charge retentions during periods of non-use, explains Steve Hicks, Ryobi DC product manager. The Power Struggle The biggest tool isn’t always the best. Before buying the one with the highest voltage, it’s best to determine how the tool will be used and how often. For instance, a heavy-duty 36-volt circular saw makes sense when cutting 2x6 framing members. But if jobs are smaller or infrequent, a lower-voltage, lighter-weight tool offers easier handling. Higher voltages also mean longer run times. So if a tool sees repetitive use for extended periods, such as nail guns used by roofers, a higher-voltage battery can eliminate the need for keeping replacement batteries ready. Jesus Gonzalez of Chicago-based JMD Home Services just bought a 24-volt screw gun. “The power lasts longer,” Gonzalez says. “It’s the same weight as our 18-volt gun, but we don’t have to recharge this one all the time.” Power fade, a tool’s diminishing performance as the battery loses its charge, is not an issue with Li-ion technology. But because tools using Li-ion batteries maintain a consistent power level, overuse of the batteries can result. Over-discharged Li-ion batteries lose their ability to recharge. To prevent this problem and extend battery life, manufacturers suggest more frequent charges. What’s New To date, manufacturers have either used the advantages of Li-ion energy density to create products with improved run times and ergonomics (typified by the 18-and 24-volt models produced by Makita, Ridgid and Milwaukee) or to replicate the performance of corded tools as demonstrated by DeWalt’s 36-volt platform, which uses innovative nanoscale battery technology developed by the Massachusetts Institute of Technology. According to DeWalt, the new technology uses non-combustible active materials and offers improved performance with a fivefold gain in power and up to 10 times longer run life than previous Li-ion batteries. The manufacturer says the batteries are safer and will cost less, too. What’s Next Harnessing this new development, DeWalt has introduced 18-and 28-volt models, both featuring nanoscale technology. The 18-volt tools include “an innovative charger capable of charging [DeWalt’s] 7.2-to 18-volt nickel-cadmium, nickel-metal-hydride and lithium-ion batteries,” says Christine Potter, DeWalt group product manager. Ryobi also has new products on the market. (See New Products, page 35.) “All are designed to optimize the lighter weight of the lithium-ion battery and provide improved handling,” says Ryobi’s Hicks. “The circular saw, for instance, repositions the battery from its traditional location at the end of the handle to the tool’s side, making it more compact and balanced.” While Li-ion power tools offer improved run times (30 percent higher) and ease-of-use, they come with a 40 percent or higher price tag over similarly rated traditional cordless tools. Consequently, users will have to determine if the productivity gains from fewer recharges and greater battery life outweigh the premium price. Battery Storage Lithium-ion (Li-ion) batteries and their chargers make recharging fast and easy. Here are a few tips for storing your Li-ion batteries properly: 1 Remove batteries from charger after they are fully charged. 2 Store the batteries in a cool, dry place away from direct sunlight, moisture and excess heat or cold. 3 For prolonged storage, keep the battery at a 40 percent charge level. Recycling Rechargeables Nickel-cadmium (NiCd) batteries contain the heavy metal cadmium, a known carcinogen. Small sealed lead (Pb) batteries contain harmful lead. Federal law requires NiCd and Pb batteries to be managed as Universal Waste and recycled. So when replacing your NiCd battery-powered tools with Li-ion upgrades, always dispose of the batteries and battery packs at sanctioned recycling sites or at the store where the tool was purchased. When their life-cycle ends, dispose of Li-ion batteries the same way. For more information and to find a recycling center near you, visit www.call2recycle.org or call (877)¬2RECYCLE. Omar Gonzalez, with JMD Home Services in Chicago, appreciates the power consistency of Li-ion powered tools. Lighter-weight tools make a difference for Chicago remodeler David Gonzalez when the job requires stamina.