What precisely does "will not function" mean?
13.1 volts DC indicates you are plugged into shore power.
Per Lippert's specs the SlimRack system should function down to 10.5 volts DC:
• Power and wiring MUST be such that there is not less than 10.5 running volts supplied at the motor leads under maximum load.
The reason why starting the generator will "fix the glitch" when shore power is connected, which is the only way you can get 13.1 volts DC, is because the momentary loss of 120 volt AC power causes your converter to reset itself into high charge mode.
You can fake the converter into high charge mode for a short while by locating its circuit breaker inside and turning the breaker off for several seconds and back on.
We run our SlimRack slide on 13 volts from shore power without problems. Our large slide takes no more than 30 seconds to extend or retract. The two smaller slides take between 20 and 30 seconds.
2020 Georgetown GT5 34H5