Helping your batteries live a long and productive life.
About half the price of a cordless drill, recip saw, or circ saw is spent on batteries. Since replacing these batteries when they fizzle is expensive, many tool users often just get a new tool. New batteries for mobile phones and laptop computers are expensive, so extending their lives will pay off, too. Here are a few simple tricks to maximize battery life and run time.
Heat. Heat is a big battery killer. A battery heats up as you use the tool; that's normal. But it overheats, however, as you overuse the tool. You should back off a bit and your batteries -- along with the rest of the tool -- will last longer. That doesn't mean babysit your tools, it just means don't drill a 1-inch hole in 6-by with your 12-volt drill.
Another heat source comes from storage, especially for users in hot climates. Leaving your cordless tools and batteries baking in your truck box, on the deck, or on a roof all day will shorten the battery's over all useful life and diminish its ability to take a full charge. This is especially true for high-drain tools like recip saws or rotary hammers. Park in the shade if possible and take tools out of direct sunlight when possible.
Cold. The other end of the spectrum is freezing temperatures. NiMH's chemical reactions stop working at 14 degrees F; Nicad gums up at minus 22 degrees F. While cold won't damage your battery like a heat wave, keeping the cells temperate will help you work better. It takes a battery an hour to assume the ambient temperature of its environment, so store your batteries inside when you can. If it's just as cold inside, Panasonic says leaving NiMH batteries in the charger warms them up in a few minutes and you're good to go. For a sluggish Nicad tool, warm the batteries inside or in your truck. Putting the tool in there too, will also loosen up the frozen grease in the gear housings.
ReCharge. Who wouldn't love a totally cordless world? As batteries and tool engineering improve, so do the chargers that gas up the battery cells. Makita and Panasonic chargers are especially advanced. They have a light signaling everything: battery too hot, charging complete, trickle charging, even a dead battery light. Both companies offer the following tips for optimizing the charge and caring for your charger:
- Charge the battery at between 50 and 104 degrees F, when possible.
- Charge the battery before completely discharged. A complete run down can cause cell polarity reversal, which kills your batteries completely.
- Never charge a fully charged battery.
- Never charge from a generator.
- Charging a battery where it's cool decreases charge time. If a charger location is too hot, the charger senses a hot battery and limits or cuts off current.
The charger itself requires little care. Blow out the port where the battery stem fits with compressed air. But trying to clear dust "out" of the charger vents will only blow it into the charger -- so don't try that. Another key point to remember is to keep your chargers dry.
Extended Charge. If you go a while without using some of your cordless tools, you've probably returned to the shop to find batteries sitting in chargers. If you go a week or two, Bosch says that's no big deal. Chargers sense a full charge and will shut off. If you leave them charging for a month, that's a different story.
Consumer Electronics
Mobile Phone/PDA. Batteries in portable devices like mobile phones and personal digital assistants (PDA's) benefit from running off a full charge. While they're designed to charge within several hours, you'll get more life out of them in the long run if you put them on the charger overnight (8-12 hours.) That also means you'll have a battery that's full of gas in the morning. Don't store either device on the charger for periods longer than that.
Laptop Computers. If you're like me, your laptop spends as much time on your desk as it does on the road. For office work, manufacturers recommend removing the battery and storing it in a cool, dry place. Charge it before going mobile. If you use your laptop on site or traveling, try to rely only intermittently on your batteries. Periodic use and partial discharges are best for longer life, especially for Lithium Ion cells. If you run your laptop remotely all the time causing deep battery drains, you won't get as much life out of your batteries.
Eventually, batteries will run down. The best way to dispose of them, according to manufacturers, is to recycle them. For more information about recycling, call the Rechargeable Battery Recycling Corporation, 877-723-1297; www.rbrc.org.
And finally, if cordless tool manufacturers suggest keeping your $200 cordless tool charger off a generator, you know where not to plug in your laptop.
