Camper Wiring question

I just found a set schematics for my F150 that show all the Trailer Tow Circuits to help me rewire a damaged 7 blade socket. and find the associated fuses. Even in a F350 or E350 with the diesel engine, the charge line is really not to CHARGE the batteries, it is to maintain the batteries for loss associated with towing.

At least in my case the 40amp fuse does not go to a relay for charge only. It supplies power for the turn signal functions as well. The charge relay is for a max of I believe 30 amps, enough for maintenance but not for charging.

I have seen and read about running a completely separate circuit with a truck to trailer connection that will carry more power and requires a larger alternator for full charge capabilities.

I don't think that a standard 7 blade socket/plug combination will carry 40 amps.

stufarmer wrote:

theoldwizard1 wrote:
I assume you have a deep discharge "house battery". Be aware, you will NEVER be able to but a "full" charge on the house batteries no matter how far you drive a day. Running your refrigerator while driving will just make matters worse.

If you plan on boondocking a lot, and are planning on using the vehicle charging system to recharge your house battery, get a DC-DC battery charger.

I didn't know that. Our new Camper ( Lance 1172) will have a Solar Panel, will that keep the batteries up ?

My solar panel does just that: keeps both my 100AH batteries charged and that's with the DC compressor fridge running. Driving the truck never charged up the camper batteries.

If you use 2 ga wire, 150 a fuses at both ends, and a 150a continuous duty solenoid (and if you alternator puts out 14+v), the camper batteries will get fully charged.
My way fully charges 4 12v 140AH batteries (depending on how long the engine runs) Also runs my compressor refrigerator just fine.

GCasta wrote:
This is a good link to explain the relay and use
http://www.rattlebars.com/mtz/basicrelay.html
You either use the 1/4" spade connector with 8GA (yellow) crimp or you can get a female plug with wires and connect with butt connectors

Thank You !!

theoldwizard1 wrote:
I assume you have a deep discharge "house battery". Be aware, you will NEVER be able to but a "full" charge on the house batteries no matter how far you drive a day. Running your refrigerator while driving will just make matters worse.

If you plan on boondocking a lot, and are planning on using the vehicle charging system to recharge your house battery, get a DC-DC battery charger.

I didn't know that. Our new Camper ( Lance 1172) will have a Solar Panel, will that keep the batteries up ?

enblethen wrote:
Don't confuse a relay with a circuit breaker. There should be a 40 amp circuit breaker installed near the connection point in your truck. They have 1/4 inch(roughly) stud to connect the wire to the stud using ring terminals.
Fords have a built in relay for power the camper.

Sweet !!
I didn't know that.

This is a good link to explain the relay and use
http://www.rattlebars.com/mtz/basicrelay.html
You either use the 1/4" spade connector with 8GA (yellow) crimp or you can get a female plug with wires and connect with butt connectors

Don't confuse a relay with a circuit breaker. There should be a 40 amp circuit breaker installed near the connection point in your truck. They have 1/4 inch(roughly) stud to connect the wire to the stud using ring terminals.
Fords have a built in relay for power the camper.

theoldwizard1 wrote:


If you plan on boondocking a lot, and are planning on using the vehicle charging system to recharge your house battery, get a DC-DC battery charger.

Interesting. Can you elaborate more on DC to DC charger? Brand, attachment etc?

I assume you have a deep discharge "house battery". Be aware, you will NEVER be able to but a "full" charge on the house batteries no matter how far you drive a day. Running your refrigerator while driving will just make matters worse.

If you plan on boondocking a lot, and are planning on using the vehicle charging system to recharge your house battery, get a DC-DC battery charger.