DC to DC Charger Recommendation to Keep Lithium Battery in Casita Spirit Topped Off

Updated 09/08/2025 | Published 07/31/2025

Question:

I have questions about a dc/dc charger. Just watched Wild RV Life install one from you. I have a 2008 Casita Spirit Deluxe and have installed a 140 Ah Li Time lithium battery. Being told that I should have a dc/dc charger to protect the battery in my tow vehicle 2014 Ford Expedition Xl 4WD and help charge the trailer battery while towing. Friend suggested the Victron 12/12 smart charger 30 amp would be all I would need. Dont have solar panels, just a Renogy 100 W solar suitcase, seldom used. Dont really boondock except for overnights at Walmarts, Cracker Barrels and Interstate rest stops. May like to do some boondocking at some point. Do not have an inverter at this time. Can you let me know what would be my best option for installing a dc/dc charger. Thanks.

asked by: Tom G

Expert Reply:

Hey Tom, you'd need a DC to DC charger that has a lithium battery charging profile like the Redarc BCDC charger part # RED36TR which has dual inputs as well and can charge up to 40 amps so it would do a great job keeping your lithium battery topped off. Which charger did you watch Wild RV Life install?

expert reply by: Jameson C

Tom G.

8/5/2025

Jameson Thanks for the reply. Wild RV Life installed the Redarc Alpha 50A but that's more than I need. Probably don't need the solar capability eihter like the RED36TR has. No plans to add solar to the roof of our Casita and the portable renogy panels have a built in controller and I installed a port by my battery that can plug in there. Is there another model without solar? Also I am planning to replace the axle on my 2008 Casita. Do you sell the Dexter #10 3500 lb. axle with the 10 degree down high lift arm? Thanks Tom

Jameson C.

8/5/2025

@TomG There is a single input version with part # RED96FR but it oddly enough costs more than the # RED36TR so it would not be what I'd go with. We actually do not sell torsion axles unfortunately.

Tom G.

9/6/2025

@JamesonC Jameson Thanks again for the info. In looking at the RED36TR it appears that maximum charging from my tow vehicle would be at 12 amps. From the info I can find about my LiTime 140 Ah battery it looks like I need to have a dc/dc charger that can charge at about 40 amps from my tow vehicle. I know the RED36TR can do up to 40 Ah using solar but i do not have solar installed on my trailer and no plans to do so. Is there another charger that you would recommend that can charge 40 amps from my tow vehicle? Thanks Tom