A FWIW Story - Had a friend who had trouble getting his Monaco Dynasty to start after it was warm. He would just crank up the genset and put a charger on it with the "Boost" giving him enough amps to overcome the bad whatever. I knew it was a bad starter since the windings were breaking down due to heat. I picked him up a rebuilt starter while we were camping in Vegas, and when I moved over to Pahrump we changed it out. Took us a couple of hours, and now he starts every time. All the above are great things to check, but starters do go out, as was the case this time as well.
FWIW #2 - I go up to our unit (when it's not in Cummins shop) and run the genset for an hour or so to charge up the batteries and cycle the A/C's, heating system, basically to run some of the coach a while and to keep the batteries up. Yesterday I learned that if the genset is running and charging the batteries, the solar panel controller stops the panel from charging as well, and the light goes out. I never noticed that before, and it does not do it when hooked to shore power. Then I noticed that the center battery switch was on, that one ties the banks together, which may have had a bearing on the Solar panel controller. I checked the fuses to make sure that I had not blown them, because I was warned not to run the engine with that switch in the on position, I would blow that heavy duty fuse. I did not turn that switch on, and specifically told Cummins to leave it alone, and in the off position. I am going to remove the knob so some dummy like me does not turn it on by accident, and keep it handy in the compartment if I need to use it, but so it does not get moved by accident. I don't have my owners manual on the PC so I cannot read that section of it to understand what and how that switch should be used.
Monty & Janet - 2007 Alpine APEX 40 MDTS
S/N - 75715 - Retired - Master Certified RV Tech