I am in the process of building a cabin in Hawai'i with my partner Marina.
We have a work camp with a deep cycle battery and a an array of solar panels strung up in some trees.
The panels charge the battery through an mppt, but today we noticed that the battery wasn't getting charged and the system was only generating 0.1 amps despite good panel voltage and ample sunlight. At first I suspected a fuse so I opened up the mppt to discover a bit of corrosion on the upper left side of the board. This made sense because we've had a lot of rain the past few days and the mppt wasn't very well protected from the weather.
Poking around with the multi-meter, a via in the corroded area that was supposed to bridge a trace from one side of the board to the other wasn't electrically connected anymore. I used some alligator clips to manually bypass this area and hooked up the solar panel and battery connectors. With the temporary bypass in place, the mppt charged the battery normally.
To make the bypass more permanent, I cut a notch in the side of the circuit board with a hacksaw for a jumper wire to rest.
Next I started up the camp stove to make some coffee and to heat up the soldering iron. I first heard of this trick of soldering with a propane stove from my friend Dominic who lives on a sailboat in New Zealand.
Then it was time to make some coffee.
I put everything back in the case and the mppt worked properly again, pulling down 5.9 amps from the panels.