How to Repair an Auto Battery Charger

Undertake simple battery charger repairs: check the wiring and fuses.

Auto or car battery chargers use 120 volt mains electricity which is converted to 12 volts to produce a constant flow of electrons to your battery. Battery chargers rarely go wrong, but if they do it's usually a fuse or the plug wiring: you can easily repair both. If you find your battery charger isn't charging your car's battery, check the wiring and replace the fuses before getting it checked out by an electrician.

Things You'll Need

• Screwdriver
• Replacement fuses

Instructions

Battery Charger Plug Fuse

1. Remove the plug on the end of the cable from the battery charger if is plugged in before attempting to repair your battery charger.

2. Unscrew the cover from the plug using a suitably-sized screwdriver. Remove the cover.

3. Check that the three wires inside the plug are securely connected to the three terminals. If any are loose, it can explain why your charger isn't working.

4. Unscrew the terminal the loose wire connects to and insert the wire into the terminal hole, to reconnect the loose wire. Tighten the screw so it holds the wire in place. One terminal on the plug is labeled "Gnd" or "T" for ground and the green striped wire connects to this terminal. Another is labeled "Pos" or "Hot" and the wire colored black, red or orange connects to it. The last terminal is labeled "Neg" or "Neu" and the wire colored gray or white connects to it.

5. Pry out the fuse from the fuse holder in the plug using a small flat-head screwdriver to remove it. Replace the fuse using the same type of fuse. The ampere rating is on the old fuse, so use one that has the same ampere rating. Simply push the fuse into place using your fingers.

6. Replace the cover onto the plug. Replace the screw and tighten using a screwdriver. Plug in your charger to check if it is repaired. You can tell if it's producing a charge by looking at the display on the front of the charger. If not, remove the plug from the socket then complete the steps in the next section.

Battery Charger Fuse

1. Locate the fuse on the battery charger. It's usually in the fuse holder on the front of the charger.

2. Remove the fuse cover. Often it has a clear flap which you pry open using your fingers or a flat-head screwdriver.

3. Remove the fuse from the fuse holder. Check the ampere rating.

4. Replace the fuse using one that has the same ampere rating. Many battery chargers have replacement fuses next to the fuse holder.

5. Plug in your battery charger. Turn on the charger to check it's repaired. You can tell if it's producing a charge by looking at the display on the front of the charger.

Tips & Warnings

• If the battery charger doesn't work after completing the steps in these two sections, you need to get it checked out by an electrician.

• Do not tamper with the internal workings of a battery charger unless you are a qualified electrician.

References

• Battery Chargers.com: Battery Charger Instructions
• All About Circuits: Wiring Color Codes