What is causing my solenoid to burn out?

[ss55]

Low battery? At room temperature 12.2 volts is only about 50 percent charged. When voltage is way too low to start an engine you can hear the starter solenoid click or chirp as it cycles open and closed because voltage is too low to hold the solenoid closed.

 

[MARK ROBKE]

Weak batteries, bad cables,(or not heavy enough cables), poor connections. Especially weak batteries. Mark.