Tracking down parasitic draw on an F-350

[CyrusL]

Hi everybody. I'm writing this up as I had a heck of a time finding my issue and I wanted to help out the next person in case they have the same thing.

We have a Fleetwood Jamoboree on a Ford F-350 chassis. We were having an issue with parasitic draw on the main battery. It would take just a few days for it to become completely drawn down. Of course, I have the house battery so I could just jump myself, but that was still a pretty big issue.

In my troubleshooting, I did the trick where I put a multimeter on the battery and pulled the fuses one by one, but none of them brought the draw down (which was super-confusing). I eventually brought the rig to the Ford dealership and they tracked it down to the propane cut off switch.

There's a propane sensor in the rig. If it senses propane, then there's a leak and it sounds the alarm and sends a signal to the propane cutoff switch go stop the flow of propane. However, if the battery dies then the system wouldn't work. So, they are built so that propane only flows if there's power. The amount of power they draw is supposed to be minimal.

Somehow, the cutoff switch failed and started drawing a ton of power. I suspect it was supposed to be drawing it from the house battery instead of the engine battery.

I have since found out that these units were notorious for failing and that current safety laws don't require them. We brought our RV to our friendly local RV mechanic and had them remove it. Problem solved.

Like I said, I'm just posting this so that if someone else is searching the internet they might find their problem. I did a hundred searches and wasn't able to find much useful.

Good luck!
Cyrus

[electrowood]

I have a 1994 Fleetwood. The propane/ CO alarm you speak of has it's power source from the aux (coach) battery and not the main (chassis). I made a schematic of the Battery Control Center to see how it functions in the two circuits. I can tell you that my BCC power is fed from both the aux and the main batteries (with blocking diodes). If you leave the unit without turning off the switch that disconnects the aux battery when the unit is not connected to shore power or generator, after a couple of weeks both aux and main batteries will dicharge. I know, I tried it. I personally like the the propane shutoff solenoid. The alarm device has a 5 year life expectancy. I have replaced mine.

Good luck, Ken

[mlo166]

As a former propane dealer, it is very important that all safety systems work as designed on your rv. Disconnecting something to save something elsewhere is foolish. The manufacturer probably had a rv unit in its past that had a propane problem which required the design with the propane sensor. Now, if you disconnect the sensor, you can expect the same problem later. Most of the RV's that came in for inspection were leaking propane in the low pressure line connectors, especially on the long unsupported tubes that fatigued after years of vibrations creating a slight split in the exposed threads of the Brass end couplers. Although not a fire hazard as much as it does make a nauseating smell over time! Thus, the purpose of the sensor if there is even a slightly detectable leak! And oh if the battery dies the system doesn't work? Yeah, the propane switch doesn't work either so that the fuel supply is off anyway!