Can An External Battery Connected To The 7 Way Plug Be Used To Supplement A Travel Trailer Battery

Published 11/02/2021

Products Featured in This Question

Pollak Circuit Breaker - Cycling/Automatic Reset - 30 Amp - Straight Mount Bracket

(68)

$8.51

Deka Jacketed 2 Wire, 10 Gauge, Brake Wire - per Foot

(323)

$2.60

Pollak Black Plastic, 7-Pole, RV Blade-Style Trailer Socket - Vehicle End

(341)

$13.25

Question:

My travel trailer battery needs a little help. Our 12v refrigerator is draining the battery overnight. I cannot add a second battery because there is no room. Our local RV dealership has fabricated a connector to use while winterizing travel trailers. The connector has the truck side 7 blade on one end and battery terminal connectors on the other end. They also used 30 amp breakers on both the positive and negative wires. The connect this to an extra battery, take it out to the trailers where they need temporary power, then they plug this in to the trailer side 7 blade. Will this work to extend my amp hours? If so, since I am plugging it through the trailer lights, can I use a lithium battery as the extra battery to assist my lead acid battery installed in the camper.

asked by: Chris B

Expert Reply:

This is definitely a way to keep power to your refrigerator and prevent it from completely draining the battery on your trailer, though I will say that it is a very unique one. With that being said, as long as you do use 30 amp circuit breakers, like the # PK54530, on the wires going to both the positive and negative terminals of the battery, it should not matter whether it is a Lithium or lead acid battery that you connect to, as long as it is 12 volt.

You will also need to hook up some jacketed wiring, like the Deka Jacketed 2 Wire # 10-2-1, to something like the Pollak Black Plastic, 7-Pole # PK12-707E. When looking at the front of this when the door is opened, the port in the 2 o'clock position will be for 12 volt power/positive side of the battery, and the 7 o'clock position will be the ground/negative side of the battery. You will also need some way to connect the wires to the external battery, like alligator style clips or something of that nature, but we will not carry these. They can be easily sourced at a local hardware store, though.

expert reply by: Lazer S