Unhooking electric from tow vehicle

[JaycoAngel]

Question for when pulling in a site for the night and not unhooking from your tow vehicle: when plugging into 30 amp service at the campground, should you unhook the electrical from your truck?

[wilber1]

Michelle.S wrote:
Wilber1, if you're referring to my post, please re-read it. If no electric (read Shore Power) I'll disconnect because the TV bats would be in the same circuit as the RV bats if left connected, thus if too much power was used could also drain the TV bats.

I wasn't referring to your post in particular but I do agree that you might be drawing the truck batteries down at the same rate as the house batteries if not connected to shore power. Might be a good idea to disconnect if you anticipate using heavier loads (ie furnace).

[Michelle_S]

Wilber1, if you're referring to my post, please re-read it. If no electric (read Shore Power) I'll disconnect because the TV bats would be in the same circuit as the RV bats if left connected, thus if too much power was used could also drain the TV bats.

[wilber1]

I never have disconnected but don't know if I am right.

Some questions.

How would being hooked up drain the truck batteries without doing the same to the house batteries?

Being part of the same DC circuit, wouldn't the converter/charger provide the same protections to your truck batteries as it does to the house batteries and circuits when hooked up to shore power?

Just asking.

[Michelle_S]

If we're stopping overnite without electric I'll disconnect Truck/Trailer, don't want to take the chance of dead truck batteries. Now stopping overnite with Electric, I won't disconnect and let the trailer converter add a little extra charge to the truck batteries. Have not had a single problem doing this.

[one_strange_tex]

The technician in my walk through for the previous 5th wheel advised unplugging the umbilical from the truck before hooking up to shore power. I occasionally forgot it and it seemed to coincide with blowing the fuse on the 12V trailer circuit in the truck, but not every time. I received no such advice on my latest 5th wheel, often leave both plugged in when reaching a site until disconnecting the truck from the hitch and have not detected any problems. If you overlap the connections, many of the clocks, etc. that run off the 12V trailer system do not have to be reprogrammed.

[Lantley]

I unplug to keep the truck isolated from the pedestal/trailer.
I do not want the trailer to drain the truck battery due to a malfunction of some sort.
Unplugging is cheap easy insurance that the truck electric cannot be impacted by the trailer electric

[azdryheat]

Hmm, I never considered disconnecting from the truck. No problems so far.

[Learjet]

GordonThree wrote:

It's also neat if I turn the trailer marker lights on, the rooftop markers on the truck come on too.

And on the DRW models you get the fender side markers too 🙂

[KD4UPL]

The OP said he would be plugged into shore power. Why all this talk of draining the battery? I always leave mine plugged in when on shore power. That way the camper converter keeps the truck battery charged. I have a Chevy so the line stays connected with the key off. I like it this way. Between dome lights, stereo, ham radio, etc. I don't mind having the truck battery on the converter while parked.

[2oldman]

Does no harm to my setup. I never like doing things I don't need to do.

[neal10a]

The trailer battery charge line power from my truck is thru a relay that is activated when the ignition is start or run. Other wise their is no power to the trailer. However when the tail and brake lights are active when the truck lights are on. I believe all late model trucks are that way-- at least that is how Ford is wired. If the truck is running while hooked to the trailer and the shore power is connected to the trailer, the trailer battery charger is active which will not do any damage to the truck alternator or visa versa. The alternator/charger will see a net reduced load which does no harm....

[joebedford]

I unplug when I'm dry camping overnight. Having run down the truck batteries by mistake, I learned my lesson.

[JaycoAngel]

Thank you everyone for your advice!
We will unplug! Just in case

[Butch50]

On Fords they disconnect trailer power when you shut the key off (or at least they used to). Rams do not disconnect power and I believe GM also stays on. I put in a disconnect relay in my Ram so when the key is off my power to the trailer power is disconnected.

Bargman Battery Isolator