Battery Charging Question

[atamians]

I apologize if this has been answered, I searched but the keywords come up with many many responses as you can imagine.

I have a friend with a new Travel Trailer. He asked me to today if his house battery is charged when connected to the 7 pin connector on his truck. My first response was no, it was only charged by the converter when plugged in but then I thought I would ask. I'm actually not sure.

Are travel trailers commonly set up so the truck can charge the house battery through the 7 pin connector?

Thank you,

Chris

[RickO]

I'm not a TT expert but I'm pretty sure the answer is no.

Rick

[lanerd]

The 7 pin connector has one pin dedicated to 12vdc. If the tow vehicle's battery is connected to the dedicated pin and the trailer end of that connector/pin is connected to the trailer's battery....then yes, the tow vehicle's alternator would charge the trailer's battery. My TT was set up this way and I would keep the TT's battery charged with my truck while traveling.

Ron

[TeJay]

Very simple to check. When in doubt connect the TV and the TT. Check the voltage at the TT battery. It's going to be something around 12 volts. Then start the TV and again check the charging voltage at the TT battery. If it's at or around 13.4 volts then yes your TV is charging the TT battery. If not then perhaps the fuse or relay activating the TV charging circuit is missing or burned out.

Our F-150, 2012 came from the factory with the relay and fuse for the charging circuit in a plastic bag in the glove box.

TeJay

[atamians]

Thanks all, he called from his storage lot. His house battery had gone dead ( I suspect he left something on) He has a power jack and I'm thinking no jack handle. Anyway he hooked up the truck and still nothing.

Interestingly enough it is a 2011 Ford F150.

I will pass this on to him and suggest he join this forum. Thanks for the quick responses.

Chris

[TonyDi]

He must not have it wired for charging. It is not difficult and can save a lot of hassles.

[J Birder]

There is a line in the 7 pin connector that is intended for charging the trailer's battery. New trucks often do not have anything connected to that line. Generally, all that is required is inserting the appropriate fuse in the truck's fuse panel.

Joel

[marcham]

The 2011 and up f150 have a relay in the glove compartment that the owner must install to activate the 12vdc output at the trailer plug. The instructions are in the owner's manual.

[TeJay]

We bought out 2010 F-150 specifically for towing. Then we bought the TT. After several months of towing and niticing a few dead batteries I went to another ford dealer that does not have a large truck inventory but I know them very well and was told this.

All recent F-150 with the towing package and the 7 pin connector will charge the TT battery. The relay and fuse are provided with each vehicle and located either in a door side compartment or the glove box. The fuse compartment is under the hood dead center. Check the fuse box lid for the location of the relay and fuse.

The service manager at the second dealer said, Yes we never install them and they won't come from the factory installed because of a safety issue. Once installed the wire to the back is hot.

My question was, "If I bought this to tow why was I not told to install the relay/fuse.???"
It's tough to stamp out stupidity!!!!
TeJay

[Cumminsfan]

Originally Posted by marcham

The 2011 and up f150 have a relay in the glove compartment that the owner must install to activate the 12vdc output at the trailer plug. The instructions are in the owner's manual.

Actually our 2010 F150 had one in the glove box.

[atamians]

I just spoke to him and he also found them in the glove box. Hopefully that will take care it.

Thanks again

Chris

[Nunyadamn]

For anyone with a Chevy, this can happen as well. I borrowed a buddies toy hauler a few years ago and found that I was not charging the batteries as we drove. Took a while to figure it out, but in my trucks case, Chevy puts a blank fuse in the fuse box under the hood as a place holder. I had to remove that and insert a fuse to get the trailer batteries to charge.

Just to be clear, the fuse box under the hood used a blank, not an actual fuse.

[SailorDon]

Originally Posted by TeJay

My question was, "If I bought this to tow why was I not told to install the relay/fuse.???"

You have to "get tough" and read the 700 page F-150 owner's manual.
I've had my 2010 F-150 for 4 years and 50,000 miles and I still haven't read the owner's manual.
I get my info from the F150 Forum.

Now I have to go install that TT relay/fuse thingy.
It's still in my glove box and I've had my travel trailer for 10 months (and 1,800 miles) and never knew it wasn't charging from my tow vehicle. Duh!