Chassis battery going dead while generator on

If these are wet cell batteries, have you checked the water levels? The first thing you need to check is the battery charger output at the battery charger with the batteries full of water. Then the output at the batteries. Then do the same with the engine running and charging from the alternator. Then come back here with the results and go from there. Not enough info yet to help you troubleshoot. Chuck

You need to start but checking the batteries and their status. IF they are good, and I doubt it if you have not had them on trickle charge, I would get new start batteries. Then you can go to the alternator and see what it is putting out at the contacts and then at the Isolator if you have one. Then you can check each battery. Also put on the generator and test each battery section too. You need to figure out what is going on and then you can find a remedy.

Check your mirror heat switch.

Lot of coaches do not charge the chassis battery just the house batteries. Mine came with an echo charger but it went out so I installed a Magnum combiner works great but lot of guys install this system at half the price.
http://www.lslproducts.net/ALS_Overview_Page.html
JR

Only the engine ALTERNATOR charges BOTH batts (or whatever your setup is 2 6v in series, or a combination of batts to get 12V one for the chassis, the other for the "house") you don't specify if the generator has its own alternator, or if the output (120VAC)of the gen is going to the 120VAC-to-12vDC pannel AND THEN to the batt. the sulfur smell probably WAS a bad regulator that overcharged the batts for a while, now the regulator destroyed itself leaving an open connection, thus ONLY draining the batts.
sure test is that when engine running disconnect +side only (very careful not to touch anything grounded with the wrench used to loosen the battery conector) only briefly each batt
A. IF the engine dies when disconnecting the chassis batt, ALT is toast.
B. if lights in the "house" dimms when coach batts are disconected, and bright again when connected... your ALT is OK (and battery isolator also).
C. when engine off generator on, try same test as B.

or beeing OVERCHARGED by only beeing plugged in, probably ended up drying the electrolite (evaporated by always beeing warm, or electrolized due to a "between plates" short).

also your battery isolator probably is shorted, because chassis batt should NOT drain using normal "house" power, also I've seen stuck boost solenoids!!!! (the ones that join both batts banks).

hope this help

Thanks all. I think the smell is from the house batteries (which were new) so I am worried that it somehow overcharged those. I think I am going to have to have all of the batteries looked at. I can't remember if my chassis ones are new or not, (but I am thinking not very old). (my mind on the other hand. LOL).

Not all coaches are set up for the generator to charge the chassis battery. On the ones that do, a bad voltage regulator could cause it to drain the battery rather than charge it. If it isn't set up to charge the chassis battery, you should be able to last more than a couple days. The battery might be toast.

Where is the sulfur smell coming from? The chassis battery or the house batteries?

check your chassis batteries...along with alternator from engine charging them..those batteries might be past toast and not able to take a charge.