2019 F250 will not charge trailer battery

[Riceball1]

@Riceball1 Let me know what you find out after hooking up, please.
This is very interesting and helpful.
Slot 65, is this under the hood or elsewhere?
Also, what type of fuse was this?

Thank you in advance

65 is under the hood on passenger side near firewall

[Txfivver]

That’s true for your 2016 Ford truck but not for the 2019 Ford trucks.

After 2016 the Ford integrated brake controller no longer needs that fuse/relay to activate the brake controller.

On the 2019 you MUST HAVE THE DOORS CLOSED and step on the brake pedal for a few seconds to activate the controller. If you try it with the door open it will not activate.

This ^^^ All three of my late model Super Duty's worked this way.

[RoJoSo]

it will not drain battery when key is off circuit is dead

good to know, Thank You @Riceball1

[Heavy Half Ton]

I’m installing a victron tr30 dc to dc charger. It will CHARGE. Unfortunately, it means running a four gauge cable from battery, through a second connector at rear of truck, and on to the charger and battery. But it will put 30 amps into the trailer battery.

[jkwilson]

I’m installing a victron tr30 dc to dc charger. It will CHARGE. Unfortunately, it means running a four gauge cable from battery, through a second connector at rear of truck, and on to the charger and battery. But it will put 30 amps into the trailer battery.

You may be disappointed in the improvement over the 15A factory charging line if that is your goal. Depends on what your battery setup is. As odd as it seems, you may see less than a 10% improvement in recharge time. This is because during the absorption phase, the battery won’t be taking much extra power even though the system can provide more.

[TheLexx]

Some folks have stated there is a wiring package to allow the truck to pass more than the 7-10 amps that trucks like my 2017 F450 are limited to. I've got the dual heavy duty alternators, so I don't see any reason why that generated energy shouldn't be used to charge the trailer batteries while I'm driving.

Has anyone installed this kit and had good results? Who's the vendor? Degree of difficulty?

[Heavy Half Ton]

I am building a DIY 280 ah lithium battery. ( All in, for $650 bucks, so almost 3 battleborn for about 60% the cost of one BB!) The charge rate of the line out the rv plug would be a small percentage of what the dc to dc charger will do. IIRC, it is a 16 gauge wire to that plug, maybe less. The voltage drop on that with any current at all is hugely significant. The dc to dc charger draws about 42 amps off the truck and feeds the lithium pack in the trailer a true 30 amps to the battery terminal. It should be several magnitudes better than the rv plug setup.
The 15 amp charging line, on a GOOD day might pass 3 or 4amps into a trailer battery after you account for voltage drop on the skinny wire and voltage differential required to actually charge the battery. Add in the higher voltage required for lithium, and it becomes even more problematic. The dc to dc will, given enough time, charge the battery to 100%. The best way to store a lithium is at 50%. So, if I hook up and drive somewhere I can get them fully topped off in a little over 4 hours. Off course with solar on the roof, it becomes a little less important, but maybe at night. :-)

[jkwilson]

I am building a DIY 280 ah lithium battery. ( All in, for $650 bucks, so almost 3 battleborn for about 60% the cost of one BB!) The charge rate of the line out the rv plug would be a small percentage of what the dc to dc charger will do. IIRC, it is a 16 gauge wire to that plug, maybe less. The voltage drop on that with any current at all is hugely significant. The dc to dc charger draws about 42 amps off the truck and feeds the lithium pack in the trailer a true 30 amps to the battery terminal. It should be several magnitudes better than the rv plug setup.
The 15 amp charging line, on a GOOD day might pass 3 or 4amps into a trailer battery after you account for voltage drop on the skinny wire and voltage differential required to actually charge the battery. Add in the higher voltage required for lithium, and it becomes even more problematic. The dc to dc will, given enough time, charge the battery to 100%. The best way to store a lithium is at 50%. So, if I hook up and drive somewhere I can get them fully topped off in a little over 4 hours. Off course with solar on the roof, it becomes a little less important, but maybe at night. :-)

You have the perfect “need” for the extra current because you have a place for it to go. On a lead-acid setup, the benefit would be much less. I think I couldn’t resist adding a current sensor to the setup with a display in the truck just to see how it was working on the road.

[Heavy Half Ton]

You have the perfect “need” for the extra current because you have a place for it to go. On a lead-acid setup, the benefit would be much less. I think I couldn’t resist adding a current sensor to the setup with a display in the truck just to see how it was working on the road.

Victron BMV 712 has that covered, it will bluetooth to an old phone I have with the victron app. Nice stuff!

[jkwilson]

Victron BMV 712 has that covered, it will bluetooth to an old phone I have with the victron app. Nice stuff!

So you couldn't resist either? Nerd!