If your tool battery contains nickel cells, it's moderately easy to repair.
Craftsman and Diehard portable tool batteries are the two main names distributed by Sears. Newer portable tool batteries often contain lithium ion cells instead of nickel-based cells; while this type of cell produces more power and weighs less than nickel cells, it's not recommended for service or repairs done on a do-it-yourself basis. Lithium cells are volatile and must be charged in a certain way; every portable tool battery pack has power surge stabilizers fitted to ensure correct charging. However, you still find many nickel-based Sears portable tool batteries around, so if you have one and it's not operating correctly, try repairing it yourself. Does this Spark an idea?
Instructions
1. Put your Sears portable tool battery on charge. Remove it from the charger once it's fully charged. Leave the battery for 12 hours or more. This allows bad cells in the battery to discharge so you can find out which cells you need to replace to repair the battery.
2. Remove the Sears portable tool battery cover. There are six or eight Phillips screws holding the cover in place, so use a Phillips screwdriver to remove them and then lift off the cover from the main battery compartment. You can now get to the cells to test the voltage of each cell.
3. Use a multimeter and set it to measure volts. Place the metal tips on the ends of the two wires from the meter onto a battery cell. The metal tip on the end of the red wire touches the positive cell terminal and the metal tip on the end of the black wire touches the negative cell terminal. The raised round knob on top of the cell is positive and the flat plate on the base of the cell is negative.
4. Read the voltmeter. A good battery cell measures 1.2 volts. If the reading is below 1.1 volts, consider the cell bad and replace it. Put a mark on the cell using a pen so you can identify it. Test each cell, systematically marking bad cells.
5. Remove bad cells from the Sears portable battery pack. If the cells are clipped in place, simply pry each cell out using a screwdriver. If they're wired in place using metal tabs, you need to use a soldering iron.
6. Heat the soldering iron, then place the tip on the cell's metal tab. Remove the soldering iron immediately after the solder melts and quickly lift the wired metal tab off the cell using a pair of long-nosed pliers. Repeat the process to remove all the bad cells. Turn off the soldering iron.
7. Purchase as many new cells as necessary from an electrical or hobby store. They are inexpensive and widely available. Take a bad cell to the store so you get an exact replacement.
8. Put the replacement cells into the battery compartment. Push them into place using your fingers so they connect on the terminals, if the cells clip in place. If the cells are wired then heat a soldering iron.
9. Put a cell into position and place the metal tab onto the terminal. Place the end of the soldering iron onto the metal tab and then introduce a small amount of solder. Let it melt then remove the soldering iron and allow the connection to cool. Repeat the process on each cell terminal. Turn off the soldering iron.
10. Replace the tool battery cover on the battery compartment. Fix it in place using the Phillips screws and a screwdriver.
11. Charge your battery for half an hour. This equalizes the charge in the Sears portable tool battery pack. Use your repaired battery pack as usual.
Tags: soldering iron, portable tool, tool battery, battery pack, each cell, portable tool battery