heya dudes (and dudettes)

I'm swaping my wiring from my F150 to my superduty. i had only one battery before, now i have two in the rig. I heard there were different kinds of isolators. i don't know if i have "the good kind". how can i tell? is there a special way i need to wire up my camper battery to my truck since i have two batteries? help!

Thanks!!

Guy

 

What you want is a relay system that only allows battery voltage to be connected to the trailer when your engine is running - this is done with a relay that has a wire to the ignition so that the relay only connects the battery in the truck to the trailer charge circuit when the key in your truck is on.

I had diagrams of this on here before - but it was one of the "LOST IMAGES" that Adrian is still trying to sort out....


The way it is wired is with a standard foglight relay tied to the ignition run position. When the engine is running - the contacts connect the trailer batteries to the battery and alternator in your truck when you have the trailer connected.

F-150 and F-100 trucks don't have any provision for that, they are not designed to pull anything that heavy even though they can with a weight distribution hitch

-The reason for the relay is so that your trailer cannot drain the battery in your truck when they are both just sitting.....

You can be in a situation where it is desirable for your truck to recharge the trailer batteies - but what you DON'T WANT is for your trailer to run down the truck battery(s) so that you have no way to get out of wherever you are..... (COMPRENDE?)

It's a safety system that ensures you can get home.

A 20 amp Robert Bosch relay works fine - same as used for lights. Be sure to put a 20 amp fuse in line with it so the relay never fries. Better yet use a 20amp self-resetter breaker.

If you need more info on this surf the sticky topic at the top of the forum, and if all else fails talk to me directly.


I KEPT F-14's and E-2C HAWKEYES in the skies for 20 years for the US NAVY!



US NAVY TECH, and PROUD OF IT!!!

 

The SD should already be wired for towing. What year is is?

 

it is an '03. it is wired for trailer, both regular 4-prong and 7-prong for elecgtric brakes. should i tap into that system somehow?maybe make an extension for my camper-to-truck plug (they are up at the front of the bed usually. i don't know if i can reach that far. Im gonna look....)

nope. my camper is only 2' long, barely enough to get straight down at the floor of the front of the bed. i looked at the connector in back, the wires are not nearly as heavy as the one i put in my F150 (i heard those 12v supply wires should be big to transfer the alternator current, especially that far). guess i could trace them down and just bring a bigger one back... ?

 

OK. I was confused about what you were wiring up. And, I'm still confused about what you're wiring up? Is it the Lance Squire? If so, and if it's like mine and has the short cord, you can do one of these.

http://www.etrailer.com/pc-VWH5W~V30133.htm

I have this setup for my camper and it charges the battery fine. It doesn't charge it super fast, but it seems to do a good enough job. I have the plug in the bed wall just behind where the fuel filler tube would be on the other side. The 12v wire should be 10 gauge, it's fused and on a relay.

 

(I desperately need to do something about all the diagrams I used to have posted in this forum...)

Look here...

As you look at a seven way connector - on the CURB SIDE (USA standard) the top outer pin is twelve volt battery charging power.

On the DRIVER side, the bottom outer pin is ground.

Now; that twelve volt charge line should only be putting out twelve volts when your key switch is in the "RUN" position (with me so far?)..

Test for it with a meter when the key is off, and the key is on (with or without the engine running).

KEY OFF should be zero.
KEY ON should be 12V.

If you don't get voltage exactly like that, look in your manual to see if there is a fuse for that. It could be blown...

*Either way - avoid hacking into wires on the stock installed system. It can become a real expensive nightmare mighty fast.

 

Greywolf is 100% right!, use the set up he describes...........You NEVER have a hook up that allows the camper to draw off the truck batt. I use the same set up with my Lance, and augment the camper batt. with a gen. while camping.