Power Supply Charger Fix - joshuarothfuss/projects GitHub Wiki

I have a lot of Lithium Polymer batteries that have been used for remote control cars, airplanes, scooters, and other random projects along the way. To support this I have 3 100w chargers. During operation 1 failed.

Tools/Skills Used

• Basic Hand tools
• Soldering Iron
• Fine Tip Wire Snips
• Mouser Electronics
• Soldering
• Electrical Analysis

Troubleshooting

The charger could turn on, but as soon as you started a charging session it would lose power and restart. I took it apart to see what was going on. After observing 3 power cycles, I found an IC that smoked when attempting to charge. I googled the number on the IC and found out that it was actually a MOSFET. It was rated for 8amps at 5MHz.

Repairing

I removed the IC will the Wire Snips and soldered on a new MOSFET. Due to my use case for this charger specifically, I used a MOSFET rated for 50amps. The maximum switching rate for the MOSFET I used was significantly slower.

Results

In the end the charger worked. Technically there is probably a performance prediction, in every application thus far it hasn't been noticeable.