[Brian]

Mine has two screws on the front face and a clasp in the rear. The cover has a handle on it and slides forward to remove. I’ve replaced my battery several times and even jumped the generator off a car once. It is independent of the house and chassis batteries and is sort of a weak link in what is otherwise a well engineered coach. Marathon put a solar charger on the roof that is supposed to keep it happy but it does not seem to do much. I have subsequently added a trickle charger that is powered off one of the convenience outlets in the neighboring bay. Hope some of this helps.

[Peter]

Have you checked to make sure your generator battery is a group 24? The gen battery is charged by the engine driven alternator, have you checked that? Also your solar panel.

I’ve never heard of anyone having a gen battery problem to have to replace every couple years, mine is 4 years old and I will replace next year just because.

Our buses are a couple years apart but it should be the same.

Later

bv

[Kevin]

Is the XLII different than an 02 H? Mine is charged only via the solar charger, no charge from house.

[Dick]

I don’t know driver. I think it’s build year difference.

Later

bv

[Archived]

If the solar charger provides ample charging current that is a good idea, but what do owners do if they store their coach inside? I would be surprised if Marathon did not enable charging from the generator alternator.

If solar panels are the only way of charging the battery a project owners might consider is to bring a 12V line from the house DC system, run it through an isolator and connect to the generator battery. That way as long as the house has current the generator battery is being charged, and if dry camping with a low start voltage the isolator will keep the generator battery from having its voltage sucked down by the house batteries.

[Andy]

Sure it gets charged while the gen is running.

[Archived]

And that is fine, except if it hasn’t been run in a long time because it is in storage nothing has been maintaining the battery and the owner has to Mickey Mouse some kind of charger when there is charging current available a few feet away.

[Steve]

Guys,

I could be wrong but I just had some work done on my Geny Battery by Marathon and I am pretty sure in my case my geny battery is charged charged from the following places: Geny itself (while running), 190amp house Alternator and solar.

I have an isolator that protects the geny battery from discharging as the house depleats. My issue was that the battery was located too far from the geny and there wasn’t enough AMPS to get it started so it was relocated to the Geny Bay.

[Dick]

Your set up is what I would expect. I would suggest you see if the connection to the house DC system is at one of the DC bus bars because if it is you have another source, and that is the inverters when the coach is in storage. I doubt if it comes from the alternator directly, but that is definitely one of the devices that charges it.

[Andy]

Jon wrote: “owners might consider is to bring a 12V line from the house DC system, run it through an isolator and connect to the generator battery.”

Jon, please explain what a battery isolator is, what it does, and how it works. Or point us to the answer. Thanks!

[Per]

A battery isolator is a one way valve(diode) for electricity. It lets electicity go TO(charge) the genny battery, not away(discharge). Here’s what mine looks like.

http://texasindustrialelectric.com/pdf/31322.pdf

[Archived]

Dick, you likely have one to protect your generator start battery from a discharge due to depleted house batteries. Mine was located in the electrical bay, toward the left rear.

Typically all sets of coach batteries should have some form of isolation protection from all other sets of batteries. If the sets can be merged it should only be when charging or by manual intervention.