Adding An On-Board Trailer Battery to Trailer for Electric Power Tongue Jack

Question:

So I received the jack and there is no indication of the amp draw. It has an internal breaker so I don’t know the size of that. Polestar doesn’t have a real website so I can’t contact them at all. The only information that I have is that the wiring from the jack is #14 gauge. So I am thinking of using a 100AH LiFePo4 battery. Thoughts? I want to connect it using #12 wire ~5’ to the #14 wiring from the jack factory wires are too short. I want to install. 12V Charger and connect that the the truck wiring so that when it is plugged into the truck and running it will charge the battery. Can you provide a 12V charger for this? Any other items that I am missing?

asked by: Steve H

Expert Reply:

A 100 amp hour battery would suffice for powering a trailer tongue jack as well as some other accessories. For this, we have both AGM such as the Bright Way Deep Cycle RV or Marine Battery part # BRW94FR. In order to charge these batteries, you'd need to tap into the trailer connector's battery charge line circuit. This is only present on seven way connections so if you don't yet have one you'll need to upgrade using the Trailer Wiring 7-Way Upgrade Kit part # HS381-9000 which is for the trailer side. I do recommend using an on-board battery as it allows for much more than just powering a tongue jack but we do have options that allow you to utilize the vehicle power directly with the Electric Trailer Jack part # EJ-3527-BBX.

Please note, if you don't already have a seven way connection on the vehicle you'll need to add one to utilize the charge line circuit which is a wire run from the vehcile battery to the trailer battery through the trailer connector. I recommend the Trailer Connector Upgrade Kit part # ETBC7 for this.

expert reply by: Conner L