Mating truck 12v with trailer 12v system?

[Dadoftheturkeykids]

Alright so I did it. I outfitted my 6'x12' enclosed trailer with 720 watts of used panels, a 200ah 12v lifepo4, a 12v fuse board, and a 1000 watt pure sine ac inverter.

So far I only have lights, an exhaust fan, a cigarette aux outlet, and usb/usbc wired up to the 12v dc side (all have switches)

And only a coffee maker on the 120v ac side.

Since my trailer is a work trailer, I will be hauling it around with my truck, which is connected with a standard 7 blade connector for exterior lights/turn signals etc.

My question is, is there a way to easily mate the 2 systems together to provide charging in both directions? The hurdle that comes to mind is the truck has a standard lead acid battery whilst the trailer has lifepo.

Should I?

 

[Dadoftheturkeykids]

Another possible hurdle is the negative side in a 12v system of a vehicle is the chassis, which I am assuming I should ground my trailer system to the trailer chassis too
(I have not yet)

Will this cause me some unforseen problems, even without joining the positive of both truck and trailer?

 

[Suijkerbuijk]

Alright so I did it. I outfitted my 6'x12' enclosed trailer with 720 watts of used panels, a 200ah 12v lifepo4, a 12v fuse board, and a 1000 watt pure sine ac inverter.

So far I only have lights, an exhaust fan, a cigarette aux outlet, and usb/usbc wired up to the 12v dc side (all have switches)

And only a coffee maker on the 120v ac side.

Since my trailer is a work trailer, I will be hauling it around with my truck, which is connected with a standard 7 blade connector for exterior lights/turn signals etc.

My question is, is there a way to easily mate the 2 systems together to provide charging in both directions? The hurdle that comes to mind is the truck has a standard lead acid battery whilst the trailer has lifepo.

Should I?

A new plug and 2x dc to dc charger .
One go from the truck to trailer
One go from trailer to truck .
One is program for lipo4
One is program for lead.
Both you set a switch on the input from the dc to dc charger.
So you can disconnect for you thake out the plug or use for charge or not.
Plug see attach files.

I cannot be held responsible for this information. own risk

 

[time2roll]

My question is, is there a way to easily mate the 2 systems together to provide charging in both directions? The hurdle that comes to mind is the truck has a standard lead acid battery whilst the trailer has lifepo.

Should I?

No issues. Just connect them directly. The 7-pin connector has a B+ and ground ready to go.

Plenty of RV trailers (including mine) have already converted to lithium and are rolling down the road every day.

 

[Dadoftheturkeykids]

No issues. Just connect them directly. The 7-pin connector has a B+ and ground ready to go.

Although this is the answer I was hoping for ... I have several questions.

My charge controller in the trailer has a profile set up to charge lithium. Would that damage my lead acid battery in my truck?

And vice versa, will the trucks alternator negatively affect my lifepo4 in the trailer?

Also, my charge controller is 40a, is the 7pin wiring harness rated for this kind of current? I think the wiring in the truck has to be at least 8awg. Does that apply to all the truck wiring, or just what runs to the 7pin connector?

 

[time2roll]

That longish wire will have enough voltage drop with any significant amps to be self limiting. And the wire has a fuse in the truck fuse box.
Probably get less power than you think.

Are the truck/trailer going to be stored connected for extended periods? May not matter with a Ford as it has an isolation relay.
Either way the solar absorption period should be short to where it does not matter. I like that my truck battery is kept charged from the trailer solar while in storage.

The voltages are not really that different.

 

[Dadoftheturkeykids]

It is in fact a '04 Ford f150. It will probably be connected more often then not, but if that's an issue I could always just unplug it when I park. Does the alternator charge up your trailer battery?

 

[Dadoftheturkeykids]

I am guessing it will be near impossible to keep my shunt calibrated lol

 

[time2roll]

That F150 has an isolation relay. When the engine is off, the charge connection to the trailer is off.

The shunt will measure all power in/out of the battery and having multiple sources of charging makes no difference. It is all in a single wire at that point and the shunt will never even know.

Yes my alternator charges the lithium battery in the trailer just fine. Slow but fine and with no issues. I have a 2001 F150. The solar does more charging while on the road than the alternator.

And likewise power from the trailer will keep the truck running if the alternator goes out in the middle of Wyoming with several hours to the nearest town with a parts store. No need to ask how I know.

 

[Dadoftheturkeykids]

No need to ask how I know.

Thanks a ton for the info