[Richard]

I’ll cut to the chase scene.

Don’t keep them merged. Install some sort of device already mentioned to trickle charge the start batteries. By merging them, you run the risk of killing all the batteries in the coach if you lose pedestal power and you are not around the coach for a day or two. Second, if you have deep cycle batteries for the house and regular cranking batteries for the engine, the engine batteries are being cycled as deep discharge when you have them merged. They are not designed for that.

Plus if merged, then you use the alternator to charge the house batteries. Yeah, I know ALL class A’s advertise that as a feature, but it’s not a great idea. It is a good way to fry the alternator if the house batteries are pretty low when you start your drive.

Stop cranking your engine and letting it idle. Does more harm than good, Diesel engine will never get hot enough to boil off the moisture while idling. If you want to put it on the road for 30 miles, that’s a great idea, but not sitting and idling. When you idle a diesel, the engine never gets hot enough for complete combustion. Two things happen, the first is that carbon builds up in the cylinders and around the injector tip. The second is the unturned diesel washes down the engine oil coating on the cylinder walls thereby increasing engine wear. So the impact of extended idling is moisture in the oil, moisture in the exhaust system, diesel in the oil, and increased cylinder wear. I am not sayin that idling a diesel destroys it, but I am saying it doesn’t have the beneficial effect that you might think. Getting it out and driving it is a much better approach. That stirs all the fluids, lubricates all the seals, and gets the tires hot which helps them resist UV.