richard5933

A little more information: 1. The 24v coach system is totally separate and not what we're talking about here. There are no connections between the coach 24v system and the house 12v system. The generator has its own 12-volt 8D starting battery. 2. All the batteries under discussion are flooded cell. 3. The setup as I got it was what was done in the original conversion in 1974 by Custom Coach. They used the 8D as both the generator start battery AND the house battery. Not a great setup since the battery is not a deep cycle and of only limited usefulness when not running the generator. This is why I'm installing a new house battery bank made of four Trojan 6-volt L16 batteries. They will be set up to run as a 12v house battery bank by being connected series/parallel. 4. The new 120v charger is being connected to the house bank to provide charge whenever we're on shore power or generator. It puts out 70 amps. This is the level of charge recommended by Trojan (approx 10% of battery bank capacity). 5. The generator is a 70s-era Kohler 12.5kw powered by a Perkins diesel. Generator model is 12.5RCOP67. Only 900 hours on the generator, and other than a few minor oil leaks which I'm fixing it runs ok. There is a battery charging circuit in the Kohler, but according to the manual it is an on/off system and will keep charging even when the battery doesn't need a charge. Sounds like a setup to boil a battery, and I won't be using this. Hence the need to come up with some way to charge the generator start battery. There are two options I see as most viable. The first is to install a solenoid to bridge the 8D generator start battery to the house bank whenever the generator is running. This would charge the 8D along with the house batteries from the 120v charger. My concern here is that the house batteries are deep cycle and the 8D is not, and also that the house batteries and the 8D have different capacities. I didn't know if I'd end up with a situation where one set would be overcharged and one would be undercharged. Or, if this would create a situation in which my house batteries did not ever fully charge. The second option is to use something like the Xantrex Echo Charger. It would siphon up to 15 amps off the house batteries whenever they are being charged and send it to the generator start battery. My concern here is if 15 amps would be enough to keep the need of the generator for 12v while running and still be able to top off the battery. The generator needs a few amps to run it's electric fuel pump and a few to keep the fuel solenoid open. This is probably my preferred option. Thanks again for any advice on making this decision.

I have been using one of these for the tires on our coach: PORTER-CABLE CMB15 150 PSI 1.5 Gallon Oil-Free Fully Shrouded Compressor With the higher 150 psi cut off it seems to have no problem adding a few pounds of air to top off the tires. I don't think it would be much good to fill a tire if it was 'really low', but then again if one of my tires is 'really low' I'm going to have the spare put on before going anywhere anyhow. Got it on Amazon for around $100. I also have an outlet on the on-board air system I could have used, but I found it much easier to maneuver an extension cord than an air hose. It was really getting to be a PITA to drag out 50 feet of air hose and try and maneuver it to all four corners. This compressor is light enough that I can easily move it about, and the extension cord is something that we use often so it's always at hand. Of course, this method requires that the coach is either on generator or plugged into shore power.

I've got a 12v house battery bank made of four Trojan L16 batteries. They are being charged by a Progressive Dynamics 9270 charger which puts out 70 amps. The generator has its own start battery, which is currently an 12-volt 8D Deka start battery. (I know, it's overkill for the generator, but it came with and is nearly new). The question is this... The charging circuit in the generator is very old-school and will probably boil the battery if used for too long. There is no alternator on the gennie, and no place to easily install one. Would it be acceptable as an alternative to use an automatic solenoid to bridge the 8D starting battery to the house battery bank? The thought is that whenever the generator is running it will be connected parallel to the house battery bank and receive a charge from the Progressive Dynamics 9270. After the generator was shut down, the solenoid would disconnect the starting battery from the battery bank, and there would be no chance of waking up in the morning with a generator start battery too weak to restart the generator. My only real concern is adding a battery of a different type and size to the house battery bank while charging. I didn't want to create a situation where either the house or start batteries would over/under charge. My gut feeling tells me that this is just going to end up being similar to bridging house and chassis batteries together for the purpose of charging off the engine alternator while driving. Interested in seeing other's thoughts on this. Thanks for your help.

Trying to get our 1974 GMC Coach up and running. Got the LP system tested for leaks and safety issues, then tried to fire up our Suburban furnace. Things overall went okay, but it seems like the motor/blower is in need of help. The blower starts really slow, squeaks a bit, then eventually starts to blow air. On 120v it's okay once it gets going, but on 12v has trouble getting up to speed. Anyone have experience either rehabbing the motor or replacing them? I assume that I'll have to pull the furnace to get to the blower & motor, but first I want to know if it's worth trying. Thanks.

There's a Motor Home Hall of Fame? Is that the same as the museum in Elkhart of something else?

This is actually our second coach. We had a 1964 GM 4106 until recently. It was converted in 1990 (we think) by Custom Coach. This new coach is a 1974 GM 4108a, and it was converted in 1974 by Custom Coach. With only 40k miles, the whole thing is like a time capsule. Condition is great, but since the conversion was done 43 years ago we'll end up replacing most of the electric/electronic components to bring it up to modern standards. I'll post a few interior photos soon.

Our previous coach, a GM 4106 averaged about 7 mpg. Mostly kept to 62 mph. That coach had Detroit Diesel 8V71 with Allison 730 automatic. Our current coach, a 1974 GMC 4108a averages about 8.5. Same speed, but the 8V71 on this one is mated to a 4-speed manual transmission.

He she is! Drove it home to Wisconsin from NJ this past week. Only 40K original miles. Interior is like 1974 all over.

Long time reader - first time posting... We just brought home our 'new' 1974 GMC 4108a conversion, and when going through the drawers we found something interesting enough that I thought it worth posting here. A little piece of FMCA history. Hope it brings back good memories. Richard