Need to add Lithium Batter and charger to 2019 RP1 - Event Date: 23 Jan 2023 - 23 Feb 2023

Hi Marv, and welcome.

Heres some comments. If I understand what you're wanting to do correctly, your items 1 and 2 are one and the same. The converter is just another name for the ac to DC battery charger.

And yes you'll want to replace that. While all Lithium batteries come with a BMS (battery management system) which should protect the battery from over/undercharge, operating at too high or too low temps, it should be considered a last line of defense only. So you should remove the converter/battery charger and replace it with one properly set up to manage Li battery charging. There is a direct replacement made by WFCO whivh made the lead acid converter you have now. Progressive dynamics also makes them.

Re your question 3 you can connect your solar charge controller directly to the battery (via an appropriate fuse, located at the battery, not the solar end). Be sure to get one with the appropriate lithium setting. And yes the solar ready option is just a couple of wires. It only adds resistance losses, doesn't really add and benefit.

There is also a 4th electrical connection to consider. You will either need to disconnect 12V tow vehicle power from your 7 way towing connector or if you need that change source, install a DC to DC converter to manage the voltage difference between your TV batters and rpod battery. This is because your alternator, like the converter, isn't set up for lithium charging.

One other consideration. Lithium batteries cannot be safely charged when too cold, so if you will be camping in sub freezing temps you will either need to keep the batteries in the heated space or buy ones that are self heating. It's usually preferred to keep them in the heated area because self heating wastes energy

Have fun on your off grid adventures.

The rpod running and brake light circuits are independent from the line supplying charge to the Rpod battery, so all your lights and backup cam will still work even if you disconnect the charge circuit which is pin 4.

But if you want to charge your new battery while kn the road you'll need a DC to DC converter, which should be connected directly to the trailer end of pin 4 before anything else splits off that line. DC/DC converters are available inexpensively on Amazon and elsewhere. If you choose to do that, get one around 20A with an output voltage matching the charge spec of your battery. And, be sure to disconnect it immediately upon setting up camp unless it already cuts off with your ignition, or it will continue to discharge your start battery.

Check my mods (link in signature). I have done what you are proposing. I have written it up with pictures.

Sorry, TV in this case means Tow Vehicle, not Television.

Originally posted by StephenH Check my mods (link in signature). I have done what you are proposing. I have written it up with pictures. You did not say which model RPod or more specifically, which model power center you have. If you have the WFCO-8955, you can swap out the converter section for a WFCO-8950L2-MBA, which is the proper board for Lithium batteries. That is what I did. I also installed a Renogy 20A DC to DC charger. I chose to run a dedicated 12V circuit for the TV and the RPod to power this and disconnected the wire from the Bargman 7-way connector at the junction box under the front corner. If the TV you have has a heavy-duty enough wire running for that, you could disconnect the wire and then run a dedicated line from that point to your DC to DC charger as Offgrid suggests. The way I did it, I have a battery isolation solenoid so when the truck is shut off, the circuit is not energized so it can't feed back through to the TV.  I did all of this because the Frontier has an "intelligent" charging circuit and the LiFePO4 battery was fooling it into thinking the battery was charged. I would arrive with the LiFePO4 battery at less of a charge than when I left the house. With the separate circuit, this solved the problem and both the Frontier and RPod get properly charged.

StephenH, while the rest of your Li conversion write up is right on the money in my book, I'm not understanding your reasoning for needing to install a separate connector for your Li battery from the TV.

We've had this discussion before a bit but there still seems to be some confusion. Maybe just on my part.

I'd like to get to the bottom of it because I think that extra connector is a complexity and potential failure point that will be a turn off for many folks, and I've not heard of other folks needing to do it.

A DCDC converter connected at the trailer side of pin 4 should give you up to 30 amps (the Bargeman connector current limit) which should be plenty for most uses, without needing another connector.

You can either feed that pin on the TV side through the existing conductor, or if that doesn't supply what you need because of current limitations or a confused intelligent charge circuit or some other reason, you can disconnect it and run another 10 gauge wire from the TV battery via a 30A thermal reset breaker. That is standard materials and procedure when you install an aftermarket 7 way trailer connector kit, Ive done it on 3 or 4 TVs now, probably you have too.

Wouldn't you have to do the same thing with a separate connector to the trailer anyway? Sorry but I'm just not seeing how a second connector adds any benefits unless you need and your alternator can safely deliver more that 30 amps charge current.