What's the Difference: Cordless batteries
If money isn't a factor for you, the choice between Ni-MH cells and Ni-Cd batteries is an easy one
Two kinds of batteries are used in cordless tools: nickel-metal hydride (Ni-MH) cells, available on Panasonic and Makita tools, and nickel-cadmium (Ni-Cd) batteries, used by everyone else.
Both types of battery packs are made from stacks of 1.2v cells that add up to the total voltage. One significant difference is the maximum amp-hour ratings for each type, which help to determine how long the battery will power a tool before it needs to be recharged. For a relative estimate of performance, multiply the voltage of the tool times the amp-hours (amp/hr) of the battery to get watt-hours (watt/hr). The higher the number, the longer the run time.
Ni-Cd batteries
(photo left, above)
- Produce a maximum of 2.4 amp/hr of current.
- Slightly less expensive to make and replace.
- Operate at lower temperatures than Ni-MH batteries.
- Made with cadmium, a toxic metal; batteries should be recycled.
Ni-MH batteries
(photo right, above)
- Maximum amp-hour rating of 3.5, 45% more than the best Ni-Cd batteries.
- Replacement batteries cost more: 18v, 3.5-amp/hr Panasonic battery at Amazon.com is $110, vs. $77 for an 18v, 2.4-amp/hr DeWalt replacement.
- No hazardous materials in cells, so batteries can be thrown away with household refuse.
