Lightning 7-pin trailer charging output

[Hammick]

I searched and I couldn't find any info. What is the current output of the Lightning's 7-pin trailer port? We are buying a Nucamp TAB 400 travel trailer that has 400ah of Lithium batteries and a Victron 3000w inverter charger. Now I'm not even sure if it's possible for the Tow vehicle to charge the batteries as it doesn't have a traditional converter (just a power distribution panel)

Some people upgrade the alternators on their tow vehicles or coaches to provide 30a of charging. Any chance the Lightning is putting out high amps through its 7-pin connector? I doubt it does as that amount of current would significantly reduce towing range.

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[bmwhitetx]

On my old truck the trailer Aux 12v (Pin 4) was separately fused. Ask me how I know! Could check the fuse diagram in the manual to see if that's the case for the Lightning and what size fuse it is.

 

[Maquis]

On the ICE trucks, it’s protected by a 30A fuse. I suspect it’s the same on the Lightning - fuse 107, probably. The charge rate of the trailer battery will vary depending on the present voltage level in the truck and state of charge of the trailer battery. There’s no way to “force” charge current to the trailer battery, it’s all about the voltage difference.
Even if it could draw the full 30A, you won’t see an effect on range. 12V x 30A = 360 W or about 1/3 of a kWh per hour.

 

[bmwhitetx]

Here's the online manual for my 2022. Shows a few possibilities (91 and 107) in so-called "under hood fuse box". Could connect a load and pull fuses to see which one, if either. One is 20A, the other 30A.
https://www.fordservicecontent.com/...d=G2251327&userMarket=USA&div=f&buildtype=web

 

[Maquis]

Here's the online manual for my 2022. Shows a few possibilities (91 and 107) in so-called "under hood fuse box". Could connect a load and pull fuses to see which one, if either. One is 20A, the other 30A.
https://www.fordservicecontent.com/...d=G2251327&userMarket=USA&div=f&buildtype=web

I think 107 is correct. I corrected my post above.

 

[Runaway Tractor]

If the battery is completely drained, it is possible it might pull more than 30 amps initially recharging. But other than that, I doubt it will be a problem for that 30 amp trailer power circuit to handle. The truck's DC-DC converter will be doing most of the work at all times since the Lightning has that cute little tiny 12 volt battery.

 

[Heliian]

The trailer battery power is for charging the brake battery and not designed for charging RV batteries. I would just use the 120v outlet.

 

[hturnerfamily]

I just added an 'extension'/adapter to one of the bed outlets to our camper, to provide 120v power ALL the time, while driving, while parked...anytime.

 

[RickLightning]

The trailer battery power is for charging the brake battery and not designed for charging RV batteries. I would just use the 120v outlet.

Yup.

 

[Dan C]

The trailer battery power is for charging the brake battery and not designed for charging RV batteries. I would just use the 120v outlet.

I dont know about your trailer but those batteries are the same. There is no separate battery for breakawy switch

 

[ytwytw]

I have attempted and the truck will complain trailer wire fault errors and shutdown power.

It's only intended to power brake, not used for charging rv 12v battery

 

[Mike G]

The TRM provides voltage to the trailer tow connector for trailer battery charging when all of the following are true:

• the TRM detects that a trailer is connected and a trailer battery is present.
• The ignition is in ACC or ON.
• The BCM load shed strategy is not active (a message is displayed in the instrument cluster, such as Low Battery Features Temporarily Turned Off or Turn Power Off To Save Battery, to indicate that BCM load shed strategy is active).

There is a TRM programmable parameters tool in FDRS that when run does configure the TRM to charge batteries. I had to turn battery charging on for my truck. It was not already turned on.

 

[SteuLight]

This is an interesting discussion as I've often wondered about similar issues.

With my old tow vehicle, the travel trailer would clearly draw power from the truck when I put out the trailer slide. With the lightning, that doesn't seem to be the case - or at least if the trailer is drawing power, it's not drawing much - as the sound and motion of the slide is nearly the same as when using the trailer batter alone.

I wonder if I need to make some changes to the TRM parameters as @Mike G suggested. Can those changes be made in FORSCAN?

 

[Mike G]

This is an interesting discussion as I've often wondered about similar issues.

With my old tow vehicle, the travel trailer would clearly draw power from the truck when I put out the trailer slide. With the lightning, that doesn't seem to be the case - or at least if the trailer is drawing power, it's not drawing much - as the sound and motion of the slide is nearly the same as when using the trailer batter alone.

I wonder if I need to make some changes to the TRM parameters as @Mike G suggested. Can those changes be made in FORSCAN?

I'm positive that the tool in FDRS simply changes a 'bit' in the TRM asbuilt to allow power to the connector pin to charge batteries. I haven't investigated whether or not it's possible in FORSCAN but would be surprised if it wasn't.

 

[Mike G]

As I said, I used FDRS to turn on battery charging in the TRM (programmable parameters tool).

Opening FORSCAN a few minutes ago and selecting the 'Easy mode' on the TRM module you can see the current settings, and it confirms that trailer battery charging is turned on.

So yeah, I guess you can do that with FORSCAN.

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