Last spring I made a posting at Jumpstarting Motorhome when Chassis and Coach Batteries are dead
with this topic.
Here, I just to sum up with a few updates on my original posting. I can't post to a topic that is over 133 days old (seems like a dumb policy to me, but...), so here is a new posting with the updates.
1. I had mentioned that the chassis batteries went dead after 5 weeks and they subsequently died after 3 weeks of storage. Both times, I went for service right afterward at the RV dealer and the second time, there was also an engine code that they picked up because I told them that the Check Engine light was on for an extended period after I did start it. They sent me to Freightliner, who determined that one of my batteries was dead. They replaced it under warranty and I bought a matching battery for C$161. I was impressed with that low price, since it was a Group 31 Alliance battery and Alliance is the distributor of Daimler Freightliner parts.
It appears likely that the chassis battery froze while the RV was in storage for the (last) winter, waiting for me to take delivery from the dealer.
2. I have spent some time trying to figure out a better jumpstart procedure for the situation I described in the OP. Here is what I now would suggest if one has this problem:
If you only have access to the front of the RV with the vehicle that has the jump battery, you want to jumpstart the generator at the front. Getting access to the battery terminals on the generator is very tricky – slide out the generator and crawl under, if you are thin. Instead, note that the generator battery cable comes inside to the electrical bay at the front driver's side. That bay has 3 heavy cables and one is connected the house battery fuse panel. That is the one that comes from to the generator, and you can jump to the terminals of the high-amperage fuse in that line. . Finding a ground is a bit tricky, because the panel is lined with non-conductive material. You need to connect to the frame. If the dead house batteries are dragging your jump battery down too much, turn off the big switch in the house battery bay until you get the generator going.
If you have access to the rear of the RV, then you can go into the house battery bay. If you need to disconnect the house batteries while you boost the generator, switch off the big switch in the bay and connect your jumper cable to the side of the switch that doesn't come from the batteries. That side goes to the generator. Fortunately, there are lots of grounds in the house battery bay.
3. I continued to be concerned about the batteries going down this winter while I store it away from shore power. It gets really cold in Calgary, so I don't want the batteries to freeze again.
My initial plan was to visit the RV every month or two during the winter and start the generator to recharge the house batteries, until the charger said it was on float charge. That would also give me AC from the generator, so I bought a 25 amp smart charger to plug into the AC plug in the electrical bay, which I would use to charge the chassis batteries.
But, a month ago, I was able to get a good deal on a couple of 100watt flexible mono crystalline solar panels (Go Power). They are lightweight. So, they are now sitting in the RV front window, which faces SW. I connected the power output from the PWM charger that came with them to the power point on my dash. The power points are connected to the chassis batteries, but they only work when the big switch in the chassis battery bay is on. I'm confident, and will check, that the panels will deliver enough charge to keep the chassis batteries up even with the extra drain from leaving that switch on. I also bought a Xantrex battery maintainer that senses when one set of batteries is being charged and drains off current to charge the other set. I set it up so that the house batteries pick up a charge from the chassis batteries (which are being solar charged). I will have to check to make sure that I get enough going to the house batteries to keep them up. Note that Xantrex assumes that you will charge the chassis batteries from the house batteries, but I'm doing it the other way, so I had to be careful not to follow their connection setup.