I went to start the '93 Breakaway recently and starter batteries could not turn the engine. Knowing the house batteries were up I then used the red panel switch to augment the starter batteries. That didn't help, and indeed seemed to make things worse. So I started the Kwyatt generator, letting it run for awhile in the hopes that it would charge the starter batts but it only charges the house batteries. I have shore power available but that doesn't seem to charge the starter batteries either. After charging the starter batts directly, when I now try to start the engine with the genset running it kicks the genset out. This all sounds like a relay problem somewhere but I don't really know how to diagnose it.

Any comments would be appreciated.

Check the condition of the start battery's first. Go get a Schumacher BT175 for cheap and load test each battery with them disconnected from each other.
Just because you charged them doesn't make them
good.
You are probably getting a huge voltage drop that is shutting down the gen set fuel solenoid.

I'd suspect the starter motor (shorted or frozen); the symptoms suggest a very large current draw when the starter is engaged. What does the dash voltmeter show when you try to start?

If the dash voltmeter drops dramatically that would indicate starter issues. If it doesn't drop very much, I'd suspect the chassis grounds and the battery terminals, and would clean them (Bad connections can also cause the starter to try to draw excess current).

Can you hear the starter solenoid closing?

Why the generator stalls is a mystery, unless its starter is connected to the engine battery, or as you mentioned, the emergency start relay is defective (shorted or frozen closed), which would parallel the battery banks and cause the current draw across all the batteries.

To diagnose that, attach a voltmeter to the house batteries and put the charger on the engine battery. If the voltmeter increases on the house batteries, it's a clue the relay is stuck.

Disconnect the house batteries, charge the engine battery, then try to start; if it cranks, SHUT DOWN IMMEDIATELY - alternators don't do well without a load. That would indicate a bad isolator.

Good luck!

Thanks Gentlemen,

Voltage meter takes a dive when key is turned to start the engine. We'll have the starter off today so we can get a replacement. This one lasted 18 years and 54,000 miles. Probably time. I'll let you know the final outcome.

Lou

I replaced the starter on mine last October, but I had over 245,000 miles on it. If you charge the batteries and it does then turn over, it is probably not the starter even if there is a huge drop on the meter.

Even on a full charge, my battery indicator will drop to less than 11 volt when cranking.

Battery connection should be checked first as any corrosion on the terminals would cause a much bigger voltage drop and slower or no cranking.

All Barths are different for sure but on mine, the chassis batteries are indeed charged by the gen set when running. Yes I have completely changed the electrical system but before I did, both chassis and coach batteries would charge off the gen set. Chassis batteries directly off the gen set and the coach batteries off the 120VAC system thru the charger. I never had isolators on my coach.

Thanks, Ed. I haven't removed the starter yet, and will do some more chasing based on your comments and those of the other folks before I do.

Nice to hear from you. By now you've been around the Country another 14 times, I'm guessing!

Lou

Oh, Lordy....They say that confession is good for the soul.

I pride myself in being sure the battery connections are good at all times, especially prior to heading out for parts unknown. So I see Ed's note above and think "Well, OK, I'll go check them again." I take off the 1st 3 connections on the Chassis (starting system) side, and the 4th comes off the terminal as if it was spring loaded. So much for the casual check.

Now I'll be charging both batteries over the next 24 hours and then will see what we've got. But I have to say, I've got that nagging feeling that there is still something else wrong, in which case I'll go up a few more posts and simply take them one at a time.

Lou

As mentioned, a bad connection can cause the symptoms - with the intervention of Okkam's Razor, you may have solved the issue.

Which offers that the principle can be interpreted as stating among competing hypotheses, the one with the fewest assumptions should be selected. Not necessarily a guarantee, but a great place to start.

Thanks, R.

Distilled to the wrench-jockey's point-of-view, check first the easiest things rather than the most likely.

The loose battery terminal apparently was not the only problem. In checking the system further, I found a blown 30-amp fuse under the dashboard (in a 2-part rubber container). I have no idea what the fuse was protecting. Replaced it.

I ran the genset for about 20 minutes. Now both sets of batteries are up. House batteries do not go above 12.21v; starter (chassis)batteries are 12.71 and seem to be going higher so I turned the genset off. Without shore power and with no genset running, I have no interior lighting and probably a lot else that I didn't get to check. Test panel above the door is completely dead, and shows no status for things like tank levels or anything else on the panel. Seems like I should have interior lights running off the house batteries, no?

More checking tomorrow when we get the starter off and can check it independently.

Lou

It's easy to inadvertently turn the house 12VDC master switch off. If it's "on", that relay could be bad.