Charging Travel Trailer Battery from Tesla

[idoco]

A note - leaving the 7-pin adapter connected to the car while the car is parked/off and the trailer has no shore power will result in a significant drop in range. How significant? On the order of 30-40 miles overnight!

I thought I noticed this on my first boondocking trip with the camper, but then second guessed my memory. However, on this recent trip I have confirmed it. I suggest anyone with a trailer disconnect the 7-pin while camped overnight. It's far too lossy to be worthwhile.

Hmmm...wonder if there is something to what you noted after all. May have to check with my trailer.

From Tekonsha Prodigy RF Brake Controller
"I was just told by the SC techs that the 12v auxiliary pin of the trailer plug is not connected on newer MX vehicles, although it was on older cars. They had no idea why this change was made."

 

[ShawnA]

I just tested my March 2018 X-100D and indeed the 12 V aux pin is dead.

Does anyone know of instructions to make it "live" again?

I need it for only utility trailer purposes - Charging the emergency brake battery and interior lights in the trailer.

Thank you,

Shawn

 

[idoco]

I just tested my March 2018 X-100D and indeed the 12 V aux pin is dead.

Does anyone know of instructions to make it "live" again?

I need it for only utility trailer purposes - Charging the emergency brake battery and interior lights in the trailer.

Thank you,

Shawn

Don't know of any instructions. Here's how I would check.

First thing I would do is get a trailer light tester. If everything else works but power then check to see if seven wires actually go into the connector. 12V should be red.

If you have seven wires then try to trace the red wire back. If you get lucky you might find a splice or junction not connected.

Last check if they pulled the fuse. 12V will be a fused connection. Someone in the FB Model X towing group posted a picture of the Model X tow connector fuse which was a 15 amp. "F105 is the micro2 fuse for the hitch connector, at least on the european models."

 

[ShawnA]

Hi Idoco,

Thank you for your response.
I do have one of the 7 pin trailer testers with the LEDs.
The 12 V LED is out all of the time.
Another thread on trailers said it was a Tesla "running change" to remove power from that pin...

I will track the infernal fuse box to see if one is "missing."

Thank You,

Shawn

 

[Jillmark99]

@ShawnA did you ever get yours powered up? If so, what was the solution? My 2016 doesn’t have power to the pin either. Would love to energize it to charge my trailer battery while towing.

 

[ShawnA]

@ShawnA did you ever get yours powered up? If so, what was the solution? My 2016 doesn’t have power to the pin either. Would love to energize it to charge my trailer battery while towing.

Hi Mark,
I am on the road without good references to TMC.
I started a thread 2 or 3 years ago with the rough title “7 pin connector without 12 volt - fixed!!!”
You need to change a wire position in the connector to the 7 pin harness… The thread shows pictures of the harnesses and pins.
Good luck - Keep me posted,
Shawn

 

[Jillmark99]

@ShawnA
Found it. Thanks Shawn. Excellent resource. I will try this on my X.

Tesla stopped supplying 12V power to the aux pin of the 7 way - Fixed!!!

Hello to Model X owners with Model X manufactured on or after March 6, 2018 and no power to the aux pin of the 7 way trailer connector, I purchased a Model X-100D on February 2, 2018 for delivery March 22 of 2018. I was fortunate that with a build date of March 6, 2018 I got the new MCU...

teslamotorsclub.com

 

[Jillmark99]

I was just about to take my wiring apart when I tested it again and it turns out I had a bad ground on my multimeter originally when testing. My X does have power on the Aux pin. Mine actually has 13 volts 24/7. I tested it yesterday as well as first thing this morning before even going close to it with any fobs and I was quite surprised to see it still had power at the pins. This morning it had 13.2 volts with the car asleep.
I did look at the wiring on my trailer hitch connector and mine has the power wire like the original picture you had posted Shawn. No need for me to switch the red wire to the opposite side like your second picture. That’s strange why wiring on mine is completely opposite to yours.

 

[Zuikkis]

I asked this a while ago in other thread but now I noticed there's already a discussion.

Euro models have 13pin trailer connector that has separate "permanent" and "ignition" supplies. Anyone know how these operate in a Tesla?

9	Orange	12v Permanent power for Battery
10	Grey	12v Ignition on Battery charging or Fridge

As discussed in this thread, I'm wondering if I can simply use pin 9 to keep trailer battery charged..

BTW I noticed there exists 12V DC/DC battery chargers:

Amazon.com

This kind of device will take for example 12.0V and convert it to over 14V so it can fully charge the battery. This probably would work well in trailer so wiring losses don't matter.

 

[DelPhonic1]

It would be nice to get an update of using the 12v to charge the trailer, as well as the trailer connector, if anyone can comment on newer vehicles?

 

[ShawnA]

Hi All,

In my service center experience with the 12 volt pin in the trailer connector, the service center confirmed there was no power on the pin.
They added that since the 15.5 volt lithium battery there has been no power to the pin.

They added that there is a retrofit in process to
restore the power to the pin in cars with the new lithium battery.

I am patiently waiting for this retrofit.

Shawn

 

[DelPhonic1]

Has anyone tried the Car Generator that hooks into a cars 12volt, into car generator, than plug the RV shore power cable into CarGenerator? In their website it says they work with full EV’s.

 

[buckets0fun]

Has anyone tried the Car Generator that hooks into a cars 12volt, into car generator, than plug the RV shore power cable into CarGenerator? In their website it says they work with full EV’s.

These are /only/ a typical inverter setup, often found within a trailer, within a transport case. Use your judgement for how many watts you want your dcdc converter/12v battery to keep up with.

 

[Zuikkis]

There was some other thread where I planned a system with Ecoflow Delta 2.

New EcoFlow DELTA 2 Portable Power Station - EcoFlow Europe

EcoFlow DELTA 2 equips modern families with backup power for any emergency. Incredibly fast charging: 0%-80% in 50 min. Be prepared, always.

eu.ecoflow.com

This is great all-in-one solution. 1kWh LiFePO4 battery pack, inverter with 1800W constant/ 2700W peak power, 12V and USB outlets ..

It can be charged either from mains or from 12V supply with adjustable current. So you could take like 10A constant from the car, without overloading the dcdc converter..