TV Alternators and Charging Lithium Batteries

[Carl Hansen]

My tow vehicle is a 2020 Jeep Gladiator Rubicon with a 240 Amp alternator.  It has a 7,000 lb towing capacity.  We are including the Lithium Pro package in our Elite I in our build later this year.  I have been reading some articles lately about the demand of charging lithium batteries puts on your tow vehicle alternator as you travel.  Some article reference the ability for lithium batteries to draw so much power that they can overheat and "cook" your alternator. Some suggest as a remedy a DC to DC charging system to "throttle" your alternator to reduce charging demand and protect your alternator.

This has given me pause for concern and with no experience charging a trailer with house batteries, I thought I would inquire of this expert panel of owners as to your thoughts.  Do you think that a 240 amp alternator would be up to the challenge or do you think I should consider adding a DC to DC charging system?

Your thoughts please?

Carl

[John E Davies]

The trailer won't charge a huge amount of amps through the small stock wiring, it just cannot happen. If you had huge cables installed, it could be an issue. What is more important is what voltage will your alternator allow? This is something you can research on the Jeep forums, and I bet the Ram owners here can help too.

FYI, my Land Cruiser only puts out 13.9 volts max, and no way would that fully charge lithiums. The truck trailer charge circuit has a 40 amp fuse in it. I added a Redarc battery to battery converter. It works fine - I am seeing 14.5 volts at the batteries -  but I have not towed with it yet.

John Davies

Spokane WA

Edited February 11, 2021 by John E Davies

[Carl Hansen]

10 minutes ago, John E Davies said:

his is something you can research on the Jeep forums, and I bet the Ram owners here can help too.

Great suggestion!  I went on the Jeep Gladiator forum and they reference a Jeep bulletin that stated normal voltage could be between 12.4 and 14.5 volts.  [The alternator] is considered a demand based smart charging system. Voltage will go up and down as required with the demand placed on it.  There is nothing in the owner's manual that gives any detail.