Charging Lithium Trailer Batteries While Driving

Updated 03/09/2021 | Published 03/03/2021

Products Featured in This Question

Redarc In-Vehicle BCDC Battery Charger - Dual Input - DC to DC - 12V/24V - 25 Amp

(87)

$535.00

40-Amp MIDI Fuse Kit for Redarc In-Vehicle 25-Amp BCDC Battery Charger

(18)

$90.00

Redarc Smart Start Load Disconnect for Manager30 or BCDC with Lithium Battery - 12 Volt - 100 Amp

(4)

$165.00

Progressive Dynamics 4000 Series RV Converter w/ Charge Wizard and AC/DC Distribution Panel - 60 Amp

(454)

$289.07

Question:

Is there a way to charge a 100amphr lithium battery in my Rpod from my Tacoma through the 7-pin wiring harness? Do you recommend a DC-DC charger and will the 7-pin wire size handle the charging? I have a 2012 Rpod with a WFCO8955PEC converter. What Prog Dyn model would you recommend as a replacement if I want the option of charging LA or Lithium batteries? Also, what happens to the 12v leads from the 7-pin connection alternator? Do I have to worry about harming my alternator if I install a lithium battery? Thanks, Bill

asked by: Bill T

Expert Reply:

Yes, your solution is a DC to DC charger as there is not a "good" way to charge your 100Ahr trailer battery using your Tacoma's 7 pin connection only. You will get some low amperage trickle-charge while hooked up and the alternator running, but not enough to fully charge your trailer battery.

For systems where your trailer batteries are rated for 75-200 Amp-hours, use the Redarc # 331-BCDC1225D 25-Amp, Dual-Input DC-DC Charger. You will additionally need three Redarc # 331-FK40, 40-Amp MIDI-style fuses. For systems with lithium battery(s) you will additionally need a Redarc # 331-SBI12-LLD low voltage disconnect as shown in the wiring instructions.

The BD-DC should be located as close to the trailer battery as possible. From the BD-DC you will need heavy cables availabe at automotive parts stores.

Regarding your WFCO power center and lithium batteries, there is a small switch on the circuit board that needs to be switched from LA to LI. I have included a link to this power center, if you scroll down to the "Multifunctional Conveter Charger" section you will see a picture of it's location and instructions.

You will not have to do anything different about the 12-volt charge line to the 7-way connector. You will not have a problem with your alternator either.