Nuts & Volts - January 2005

Near Space

pins are closed to the leaf contacts (in my charger, this is on the left side of the leaves). Now, solder the leaves together (the leaves appear to be made of brass). After the solder cools, remove the heatsink clamp. The leaves will remain in contact if the soldered connection is good.

The next step is to connect wires and connectors to the charger that can interface with the modified cell phone battery. Cut two lengths of wire (red and black) about 8” long. For my charger, I used #22 AWG stranded wire. We can get by with thinner gauge wire on the charger unit than on the battery because the charger recharges the battery at a low current, whereas the battery may be discharged at a high current.

Crimp and/or solder the same type of connectors used in the battery mod to one end of both wires. Now strip about 1/4” of insulation from the other ends of each wire and tin them.

Slide a short length of heat shrink tubing over the wires and push them away from the bare ends of the wires and close to the crimped connectors on the other end (you want to keep the heat shrink away from where you will be soldering). Thoroughly tin the battery charging pins.

If the front of the charger is pointed at you (the front of the charger has the two LED indicators), then the right charging pin is negative and the left charging pin is positive. You can verify this by looking at the charging circuit’s PCB silk screening.

Pass the two #22 AWG gauge wires through the two charging pin holes in the pocket of the charger case. Be sure to pass the black wire through the right hole and the red wire through the left hole. Press one of the tinned ends of wire into contact with a tinned charging pin and heat both of them with a well-tinned soldering iron. Hold the wire in place until