Battery Disconnect

scatter · 07-08-2007, 09:05 AM

I need to pull the starter and do some other electrical stuff and want
to disconnect the batteries to keep the sparks from flying. Two
questions.

1) Does anyone know of an easy way to disconnect the batteries on the
6.0 setup? Dropping both of those batteries and pulling off the cables
is a real hassle and there must be an easier way.

If not, I might cut the main cable coming out of the batteries and install a
shutoff switch on the frame rail.

2) Any ideas on the amps pulled when starting so I get a big enough
switch?

Appreciate any ideas on this.

Scatter

Ford_6L_E350 · 07-08-2007, 11:35 AM

The batteries are grounded to the frame just above the remote start post; right behind the batteries. Remove and isolate that ground and you are good to go. The isolater should keep the camper batteries out of the picture, but you may want to disconnect it also.

Starting the diesel takes several hundred amps, but not for very long. Check into racing requirements for an external battery shutoff switch. Probably Summit Racing carries them.

Mike

scatter · 07-08-2007, 03:36 PM

Thanks for the reply Mike. Your info and thinking are right on with my thots. I have tried removing the grounding strap, but there is still power to the rig. I hadn't thot about the isolater, will check it. Maybe the ground is feeding back through my winch? I guess I need to crawl under there again and follow some wires. Dropping the batteries and disconnecting the cable is just too tough to do. There must be a better (faster) way.
Again, thanks for the input.

**BroncoHauler** · 07-08-2007, 04:03 PM

If you decide on installing a master battery disconnect switch (maybe not a bad option for SMB to offer), here's a good source. I've bought a few things from them, and they provided great customer service.

http://www.rallylights.com/hella/switches_kill.asp

Herb

**BroncoHauler** · 07-08-2007, 05:20 PM

BTW, at least on the F series, I believe there are separate grounds to the frame and to the body.

Posting your question on TheDieselStop.com might get additional insights. There are a number of Ford factory experts, and a number of Ford dealership diesel technicians, who are regular contributors to that site. Discussions are primarily centered around the F series, but you never know. Now that I think of it however, with all the additional electrical work that SMB puts into their conversions, they may not be able to help all that much...

Herb

Ford_6L_E350 · 07-09-2007, 08:49 AM

Quote:

I have tried removing the grounding strap, but there is still power to the rig.

Pat,

My factory electrical manual shows the battery ground only goes to the frame, right behind the batteries.

When you say you still have power, is that to the camper or to the van? The house batteries are still active, but the isolator should keep them out of the van circuit. In our van, the isolator will switch the house batteies to the van circuit when the solar charges them above 13.6V, so it is probably best to disconnect the isolator also.

Mike

scatter · 07-25-2007, 02:52 PM

Well, for those of you that are following this thread, I finally got around to doing this work. I disconnected the negative side of the battery from the ground to the frame. Still had power. Disconnected the coach battery, still had power. Covered the solar panels, still had power. Finally got mad and cut the negative winch power cable and bingo, no power. I had called Warn and was told by their tech department that there was no connection between their negative cable and the frame of the winch.
After all the above, I called Warn again and the guy said, "well, there is a little power flowing thru there, but not much". I guess "not much" depends on whose wrench is across the terminals. When you short something, "not much power" will keep flowing until a fuse blows or something burns out or melts through. Arrggg - why not just a straight answer.
Anyway, I couldn't find a disconnect switch in time for a trip, so I swedged on a couple of terminal ends on the cut winch negative cable and bolted 'em together. Now I have two bolts to remove, instead of one, when I need to cut all power to the rig. Thanks for the input guys!
Life moves on....

Jeffrey · 07-25-2007, 04:10 PM

Amazing. How did you even think that the winch was involved?

scatter · 07-25-2007, 07:20 PM

Well, I wired the winch directly to the battery so it was the first thing I thot of. That's why I called Warn in the first place hoping that it was isolated and I wouldn't have to disconnect it. I was pretty happy with the advice I got, but as I said, it was wrong.
But, all's well now.

bluedog225 · 07-20-2009, 08:30 AM

I'd like to install a master disconnect. Wouldn't it be better placed right to the battery and on the positive terminal cable? (1995 v8 gas).

Why try to cut off the negative? Seems like you could always be the ground while you were working and get zapped.

I'm still leaning about the 12v system.

Thanks

Tom