DC to DC Charger and Wrangler JLU eTorque

MrGneissGuy

This is a long read, so apologies, but there's a lot to it...

I recently posted a question(s) regarding switching to lithium in my 2015 T@G, and thanks to reviewing older discussions and the nice folks that answered my questions, I think I have the information I need with the exception of one thing...there seems to be differing opinions on whether a DC to DC converter is necessary to avoid draining your TV battery and/or damaging your TV alternator.

Which brings me to a topic I have not found discussed in this forum or the T@B forum...

My 2021 Wrangler JLU does not have an alternator. I have the 3.6 engine with eTorque. It's really hard to explain what that is, so I'll just quote JD Power's website...

In a powertrain fitted with eTorque, a belt-driven motor-generator unit replaces the conventional alternator on the engine. This motor-generator unit performs several functions in addition to the standard operation of the alternator, which is to provide electricity to keep the vehicle's battery charged. But in an eTorque-equipped vehicle, the electrical system is significantly different than in a conventional vehicle.

With the eTorque system, the motor-generator supplies electricity to a dedicated battery pack used to gain several advantages. The motor-generator unit delivers a 48-volt current to a 430 watt-hour lithium-ion nickel manganese cobalt-graphite battery whenever the engine is running. The battery pack array includes a 3-kilowatt direct current-to-direct current (DC-to-DC) converter that changes 48-volt current to 12 volts. This enables it to power the vehicle's accessories, which run on a typical automotive 12-volt current. Also, it allows it to charge the vehicle's conventional 12-volt lead-acid battery.

The motor-generator also creates electricity during deceleration and braking through brake regeneration. This process captures energy that otherwise would dissipate as waste heat. That energy flows to the 48-volt battery pack for storage and keeps the battery pack at a proper charge level."_

Essentially, my Jeep has a 48 volt lithium battery instead of an alternator, and it already has a DC to DC converter built into it. I have no idea what that all translates to when connecting it to my T@G after I put a LiFePo battery into it. I don't even know what the means with a deep cycle battery in my T@G, truthfully.

While we were deciding if and what to purchase regarding teardrops, I actually asked a few of the dealers/manufacturers
a.) will the eTorque actually charge the trailer's battery while driving like a normal alternator will? and
b.) will there be any issues doing so (damage to either system)?

None of them actually knew the answers. They guessed that all would be well. I've towed my T@G home from the dealer, an hour drive, and a round trip for our maiden camping trip with it, an hour each way, without noticing anything unusual in Jeep's battery system (no significant change in voltage while driving). I currently have no way to tell what is going on with the trailer's battery/charging system while I'm driving.

I've ordered my LiFePo battery (Renogy smart battery with bluetooth module). With the bluetooth, I'll be able to monitor what's happening with the LiFePo while towing when it all gets connected, and just to be safe, I also ordered a battery disconnect switch (my 2015 doesn't have one) so if there are issues I can just disconnect it from the TV.

Does anyone here know about the eTorque system and how it works with the T@G's electrical system? With its DC to DC converter, is there a need for another one on the T@G's battery when I switch to LiFePo?

zgfiredude

I "feel" like the following: Given that the eTorque's output is through a DC/DC converter, I'd go with that at that point in the system (downstream of the converter) it is simply a 12v system. If you access that 12v system, I'd surmise that charging of the T@G trailer would behave as "normal". I would be inclined to let that charge happen without any alteration, and then just augment the charge of the trailer's lithium battery with solar and a solar controller that will recognize the lithium battery. From what I have read/know, the TV should charge the trailer battery to +/- 80% and perhaps more....but the solar can then top it off.

This is all coming from my acquired knowledge of reading a lot of material along my path to an auxiliary battery in my NON-eTorque JKU. I did recently stay in a Holiday Inn Express as well.

Good luck.

HikinMike

I have a 2022 Wrangler JLU 4xe. One option is a trailer towing package which has a 4 and 7 pin connector. I would think all would be well.