Hello everyone, I just changed the three motor starting batteries for the Cummins. Much to my surprise after the coach sat for 2 weeks, I went out and tried to start and barely cranked over, I hit the boost and she started. Once I let it run for 10 minutes or so , I tried to restart without the boost , and it started fine, is there any type of charging in the coach that Foretravel would have installed for the motor batteries when plugged in. Even if I leave the boost switch on the motor batteries are not charging. My mechanic seems to think I may have a relay stuck or a light left on in a belly bay or something like that, any help would be appreciated!! Thanks Bob in Ct
No, from the factory, NO means of charging chassis batteries.
If leaving the boost switch on does not charge them, then indeed you have a bad boost solenoid.
Two weeks is about right. Parasitic draws are discharging the battery.
Unless you disconnect the batteries at the negative terminal to eliminate the parasitics, your solution is to add a trickle charger, battery tender, or battery minder. The boost switch should also work, but is a last resort. All these solutions require the house batteries getting charged somehow.
If boost switch was bad then it should not have started after he activated it....... would have made no difference.
He stated that he hit the boost and it started, I'm a bit confused as to how it could help start without allowing them to charge also.
Two weeks discharged can damage the engine start batteries permanently. Don't ask me how I know that
Install a Trik-L-Start so that when you have power your start batteries stay charged up.
Good catch. That REALLY doesn't explain symptoms.
You are right-- how would boost allow starting but not allow charging?
Verify which circuits are on the engine battery with a test light on the fuse boxes. Then use one of the plug in volt meters as you remove active fuses. The culprit circuit will show a lower volt reading until it is removed .
Ice, can't help without know year & model of your coach.
Did the OP mention what brand of batteries he had and how old they are? I'm as confused as the rest. The dual charge system we have ALWAYS keeps the start batteries up to snuff, as well as the house when we're plugged-in at the pier. I have NEVER had to use the boost switch or the block heater, even at 20 degrees when dry camping.
Mike, your coach being a 93 is all mechanical I think, so you probably don't have the parasitic drain that the electronic controlled units have.
Wish mine was totally mechanical.
Ah ha! Thanks for the heads-up. I've never heard the term 'parasitic drain', but I've dealt with some customers that had it! ^.^d
We also installed a Trik-L-Start (on bulkhead under bed) and that took care of the problem.