Completed Solar/LifePo4 Install in Travel Trailer

[revilo]

Hi All,

Just completed my solar/lifepo4 install and wanted to thank everyone for their help and contributions on this forum. I haven't had the chance to run it through it's paces but happy that everything worked post install!

Setup details:

1 - Jaboni 100W Solar Panel (factory installed)
2 - Renogy 100W Solar Panel's added
3 - Solar panel 30A fuses for panel's wired in parallel
1 - EPEVER MPPT 4210AN
1 - Victron 12/12 DC-DC 18 Amp Charger
1 - Aili battery monitor
2 - 100AH SOK LifePo4 Batteries

It took a lot to think about how to tap into the factory wiring when moving the batteries inside and adding the DC-DC controller but was able to figure it all out. I chose not to add an inverter, but should I decide to do so I will need to upgrade the 6AWG ground wiring that was factory ran.

I haven't charged the batteries using the DC-DC through the 7-pin connector yet to see how many amps it pushes, will be curious to see as that was one of my biggest questions. My tow vehicle is a Jeep GC and I didn't want to run a wire from the engine compartment and have a dedicated connector. I think Solar will provide most of my needs, but it will be great to also charge as I'm driving and not have to worry about draining the Jeep's battery.

Also, as most people have said, programming the EPEVER was a bit of a bugger. I ended up connecting the controller to the laptop and used their software to configure. I've attached the settings file for those that might want to simply do an "import". Use at your own risk... I sent it to Min at SOK battery as well, but I believe the settings are appropriate for LifePo4.

Anyway, if anyone has questions, happy to help! Feedback is welcome as well! Thanks.

 

[Kennedyma]

It looks fantastic, nice work.

You should be able to to get close to 18amps with the 7pin. Do you know how big the wire is from the battery to the 7-pin?

 

[revilo]

Thanks!

TV --> 7-pin = 10awg (I believe)
7-pin --> TT = 6awg (looked that way)

 

[HRTKD]

Just to be on the safe side and keep the batteries from moving around - that rubber bungie cord looks a bit sketchy to me - I would get some 1" angle aluminum and run it along the three exposed edges of the batteries. Screw the aluminum into the floor.

What does the backside of the batteries look like? What are they up against? Another line of angle aluminum back there might be appropriate.

 

[revilo]

Thanks Jim. Yes, I plan to secure them better and build a cabinet around them so they are not impacted by other items in the storage while in transit. They are butted up against angle brackets that are drilled into the floor to keep them off the electrical components.

I did want to as you about the DC-DC and running both negatives to the common bus. It's my understanding that it's basically turning the "isolated" unit into a "non-isolated" unit, but should work properly. It certainly seems to be charging.

 

[HRTKD]

I think your plan for the DC-DC charger is right on the money. You won't drain the tow vehicle's battery. Most modern vehicles with a tow package shut off all power to the 7-pin connection when the vehicle's ignition is off. On my F-350 it won't provide power unless the engine is running and I press the brake pedal.

 

[bagmanmike]

I only get 7 amps into a low SOC LiFePO4 in my Lance from my 2020 JGC Trailhawk at 14.6V. I've not dug into where the loss is yet.
Power remains on when the Jeep is off.

 

[HRTKD]

I only get 7 amps into a low SOC LiFePO4 in my Lance from my 2020 JGC Trailhawk at 14.6V. I've not dug into where the loss is yet.
Power remains on when the Jeep is off.

Even after 20 or so minutes you still have power to the 7-pin???

 

[revilo]

I only get 7 amps into a low SOC LiFePO4 in my Lance from my 2020 JGC Trailhawk at 14.6V. I've not dug into where the loss is yet.
Power remains on when the Jeep is off.

I haven't tested amps yet, as the batteries were basically full. Mine definitely shuts off. It shows in the victron app that it detected engine shut down and turns off the DC-DC.

 

[bagmanmike]

Even after 20 or so minutes you still have power to the 7-pin???

All night. It was the same on my RAM Rebel as well.

 

[bagmanmike]

I haven't tested amps yet, as the batteries were basically full. Mine definitely shuts off. It shows in the victron app that it detected engine shut down and turns off the DC-DC.

My current was direct and no DC-DC in circuit. So I disconnect at night now so I'm not charging the Jeep since it "floats" lower.
And to add to my HRTKD reply, I use a 7 pin adapter for my macerater pump and it definitely is live all the time.

 

[HRTKD]

As much as the Superduty guys bitch about getting power to the 7-pin - it really is a strange setup - I don't think they'll object to having the power shut off when the engine is off. The last thing you want when you're out in the boonies is to run your tow vehicle's battery down so far that it won't start.

 

[Kennedyma]

I haven't tested amps yet, as the batteries were basically full. Mine definitely shuts off. It shows in the victron app that it detected engine shut down and turns off the DC-DC.

I think this is the key. The Victron unit will sense when the ignition is off, by the drop in voltage. It's a really nice feature of it. I have the 30amp version my Wrangler to keep my house battery topped up and love it.

Thus you may still have power to the 7-pin, but the Victron unit shuts off.

 

[Kennedyma]

@revilo One other thing. How come you combined the circuits? Depending on how things are wired, you can have back feed issues. Where the trailer battery will back feed power to the car.

 

[revilo]

@revilo One other thing. How come you combined the circuits? Depending on how things are wired, you can have back feed issues. Where the trailer battery will back feed power to the car.

@Kennedyma, are you referring to the 2 negative wires coming off the DC-DC to the bus bar? Or are you referring to the circuit breakers?

 

[Kennedyma]

Looking at the negative bus bars.

I get why you did it and it's not terrible, but you can have issues.

 

[revilo]

To be honest:

1) I didn't want to run another ground cable direct to the 7-pin ground
2) I wasn't sure if I could run a single ground to either the input or the output of the DC-DC, so I ran 2.

I'm not sure what issues it would cause. I've read about issues like ground loops, etc.. I would appreciate any insights that folks have on this issue as that was certainly something I was struggling with. As I mentioned, everything seems to be working fine! But, if I'm setting up for issues later, it would be great to know what they are.

Also, it seemed that you can have isolated/non-isolated DC-DC and this basically made it a non-isolated.

Thanks.

 

[Jasgt]

Hi all,
thanks for posting @revilo. How do you have your panels mounted to the roof of the coachmen? What fasteners did you use? Trying to get my done this weekend and after inspecting it looks like it’s just foam core roofing.