Starting Engine


Senior Member
Having a senior moment right now so be patient, please. Do I have to unhook the shore power line if I want to just start the engne and run it for a bit? I think I use to put the shore power liine back in traveling mode when I would run the engine. I always unhook the battery when I am connected to shore power. I always like to do a start up about once a month to just to keep engine parts lubed, etc. I think I can do it without disconnecting but must make sure I don't have batteries on dual.
Just thought of another question. The power converter, how do ya know if it is going bad or is starting to go bad? Any checks I can do to check this? :dead: ;)
Re: Starting Engine

Archer, I start up Nellie bell at least once a week and i don't disconnect anything. I have a coach battery and chassis battery and stay hooked up to shore power of course Nellie Belle is a 1978 model. As to checking out the convertor they ususally just crap out.


Senior Member
Re: Starting Engine

well, a converter takes 120v AC and produces 12v DC. This 12v is used to 1) recharge the batteries and 2) power the 12v circuits in the RV. So if the batteries are disconnected and the 12v stuff is not working right, then the converter may be bad or on its way out. If the batteries are connected and won't stay charged, the converter may be bad or on its way out. Of course, the batteries may also be bad or on their way out. About the only check you can make is put a voltmeter across the batteries and ensure an appropriate charging voltage, and across the main 12v supply (at the breaker panel). To test the batteries, you can use a load meter (NOT a voltmeter) and/or a hygrometer (to test the liquid in each cell).


Senior Member
Re: Starting Engine

There is no reason what so ever to disconnect the shore power just to start the chassis engine. While the chassis can and will supply power to the 12V side of the RV, it won't harm anything in the short term if you still have the converter in operation. I have done that many times.

On starting the engine, I talked with the Ford Chassis Hot Line folks back when we bought our motorhome about this very practice. They say that if you are going to start the engine, you should do so every seven to ten days, but that it is very bad to do this unless you plan to actually drive the RV for at least 20 miles. They advised that the hardest thing that is done to a motorhome engine is the "dry start." Ford defines that as a start where the oil has all had time to drain back to the sump and none is still on the surfaces. They say that with most oils that is two weeks. It was their advice to not start the engine at all, when the motorhome is parked for long term. They advise that if it is to exceed one month, a fuel stabilizer should be used and the battery should be connected to a float charger. We have now been fulltime in ours for nearly seven years and we have followed that advice. We usually sit in one spot for an average of three months at a time and have stayed as long as five months. I normally start the engine and warm it up as a test just a few days before we are to travel, and let it sit the rest of the time. It has worked very well for us.

Don't forget that the genset is a different issue. It should be run for at least 1 hour each month with 1/2 of that time at 1/2 to full load.
Re: Starting Engine

It depends on your converter. The new ones are protected by large built in diodes that prevent damage but the older ones(mid 90s) don't always have that protection. Worst case senerio is that you burn out your converter. The worst of the converter burnout problems was with Todd Industries Power Source converters. I think All PD9100 and newer are protected and so are the 6300Q models and newer. The Pre Q models would burn out the ballast resisters.