Batteries offer portable power. Dozens of things in everyone's home run on batteries. Some household batteries are use-and-toss while others use a recharger to replenish their stored electricity. They include household battery rechargers (AA, AAA, C, D batteries) as well as all the new shop tools (drills, saws, vacuums, etc.) that run on special rechargeable batteries. Let's visit the Fix-It Club to find out how to keep all those batteries charging.
How Does It Work?
Household battery chargers include a transformer and a circuit board--not much to work on unless you're an electrical technician.
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Many cordless appliances are powered by a rechargeable nickel-cadmium (nicad) battery or battery pack consisting of as many as 20 cells. Each cell provides direct current at about 1.2 volts. Batter packs slip directly into the appliance or tool or have snap-on terminals. Some battery packs have built-in batteries that cannot be removed; they must be charged in the unit.
What Can Go Wrong?
Lots of things can happen to rechargeable batteries, none of them unsolvable. Rechargeable batteries lose their power. Electrical contacts may not be making full contact. The charger may be defective. Batteries wear out or become defective.
Fix-It Tip
How long will rechargeable batteries last? As many as 1,000 recharges. To get the most from rechargeable batteries, read and follow the instructions that come with the recharger unit.
How Can I Identify the Problem?
If a cordless device (with built-in rechargeable battery) doesn't work, lacks power, or does not run long enough, make sure power is on at the outlet and that the outlet is not wired into a wall switch that has been turned off. Also check the electrical cord and replace it if it is defective. Test the recharger unit (see below) and replace as necessary.
If a cordless device or rechargeable batteries run for shorter and shorter periods between rechargings, the nicad batteries are probably worn out. Inspect them for damage or leaks and replace as needed. Test the recharger unit (see below) and replace if not working.
If there is no leakage visible, test the battery pack and replace if necessary.
Fix-It Tip
Batteries, too, have Senior Moments as they begin to lose energy, and memory becomes a problem. Read instructions that come with the recharger and batteries. Many nicad batteries require a full discharge before a recharge. Otherwise, the battery gets a smaller recharge each time until it cannot retain a charge. Fortunately, battery discharge units are relatively inexpensive. Camera stores have them for video camera batteries. Electronic stores offer them for other rechargeable batteries.
What Parts, Materials, and Tools Do I Need?
There really aren't any replacement parts available for battery rechargers--except the rechargeable batteries themselves. You can open up the rechargers and check for obvious damage, such as a disconnected electrical cord , and clean internal contacts, but that's about all. Here are the tools you'll need:
- Screwdrivers
- Small file
- Electrical contact cleaner
- Multimeter
Restore full electrical contact:
- Unplug the recharger from the electrical receptacle.
- Use a small file, emery paper, or electrical contact cleaner to clean the contacts between the power handle and the charger.
- Move the power unit in and out of the charger several times to be sure it makes full contact.
Test a DC output charger:
- Set a multimeter to the 25 DCV (direct current volts) scale.
- Plug in the recharger to the electrical receptacle (outlet).
- Touch the two multimeter probes to the appropriate charger contacts (+ and -). If the meter reads zero volts, reverse the probes.
- The DCV output should be at or slightly above the charger's rated output. That is, a 9VDC charger should give a reading of about 10VDC.
Test an AC output charger:
- Set a multimeter to the 25 ACV scale.
- Touch the two multimeter probes to the two charger contacts. If there is no reading, the transformer is faulty. Check an electrical supplier for a transformer of the same rating and size.
Test a battery pack:
- Completely charge the battery pack.
- Set a multimeter on the DCV scale larger than the battery pack's rated output.
- Touch the red multimeter probe to the pack's + terminal and the black probe to the - terminal.
- Replace the battery pack if the reading is more than 1 volt below the rated output (8VDC for a 9VDC pack).
Fix-It Tip
Need to get rid of some old rechargeable batteries? Call your local solid waste management service for specifics because some locations don't allow rechargeable batteries to be included with household trash. The store from which you purchase the replacement batteries may know about local regulations.