Home Care

The pros and cons of duct cleaning; what DIYers need to know about the electrical code.

Cordless power used to be easy to figure out—

voltage was everything. But with lithium-ion (Li-ion) technology, most full-size tools use an 18-volt battery, usually comprising five individual cells of 3.6 volts (5 x 3.6 = 18). This five-cell stack has become the sweet spot for power, run-time and battery weight/size. Improvements in the tools, such as the addition of brushless motors, also help batteries run longer. More important than voltage is the battery’s amp-hour (Ah) rating, which tells you how long the battery will work effectively. For a battery rated at 2.0 Ah, you can draw 2 amps for 1 hour or 1 amp for 2 hours. Theoretically, anyway. The actual run-time also depends on the task, the battery’s charge level and the temperature. Most single-stack 18-volt batteries offer 1.5 to 3.0 Ah. Highperformance batteries, stuffed with more and/or highercapacity cells, can reach 5.0 to 9.0 Ah. These are typically for powering chain saws, compound miter saws and reciprocating saws. Some high-demand tools use two 18-volt batteries to boost the power to 36 volts.