Emergency Start Switch

[KatanaPilot]

The description of the MBS chassis based Isata 3 indicates presence of an emergency start circuit. Questions have been asked previously on the Solera/Forester/MBS forums about availability of such a circuit for those RV's and the answer seems to be "Mercedes doesn't allow it". So now I'm confused. If such a circuit is allowed, is there any possibility of getting a wiring diagram with component part numbers so we can install something similar in our RV's? I plan to store our RV at storage facilities across the country on occasion and the ability to "jump start" from the deep cycle coach batteries (by push button, not cables) would be a huge plus for me.

Thanks in advance.

[AquaMan]

The problem exist that if your chassis battery is dead, there's a chance that your coach battery(s) may be as well. That aside, all that would be involved would be a switch, a relay, cables running from coach to chassis, and an isolator.

[bclemens]

There was some confusion because the Mercedes-Benz owners manual said not to tie into the chassis electrical. On further review with Germany that was more for the retail consumer, not factory up fitters. They may be doing the start switch there now...I can only confirm that Dynamax is.

[KatanaPilot]

Originally Posted by bclemens

There was some confusion because the Mercedes-Benz owners manual said not to tie into the chassis electrical. On further review with Germany that was more for the retail consumer, not factory up fitters. They may be doing the start switch there now...I can only confirm that Dynamax is.

That's good to know. Is there any possibility of a wiring schematic showing how Dynamax installs this circuitry? It would help assure that I do it the same way the professionals do.

[KatanaPilot]

Originally Posted by AquaMan

The problem exist that if your chassis battery is dead, there's a chance that your coach battery(s) may be as well. That aside, all that would be involved would be a switch, a relay, cables running from coach to chassis, and an isolator.

I plan to solar charge my deep cycle batteries, plus I can easily isolate them from the coach. I also know I can disconnect the chassis battery in the cab under the dashboard, but I'm just trying to add some fault tolerance to leaving the coach unpowered for an extended period.

I know it's not a difficult install, but don't want to risk running afoul of the MB warranty service folks.

[bubbles]

Originally Posted by AquaMan

The problem exist that if your chassis battery is dead, there's a chance that your coach battery(s) may be as well. That aside, all that would be involved would be a switch, a relay, cables running from coach to chassis, and an isolator.

The switch is a momentary and just the positive battery cable need be routed to relay (contactor) as all batteries use chassis as ground return. Batteries are isolated otherwise and don't see an issue with "if one is dead so is the other".

[KatanaPilot]

After further research and a little digging, it turns out the capability for an emergency start switch is already in place on the MBS FR motorhomes. I will post my findings and pictures of my install on the MBS sub-forum once I complete it.