Troubleshooting Voltage Drop from Vehicle Connector to Trailer Battery

Updated 08/02/2017 | Published 07/31/2017

Question:

I have a group 65 battery in my enclosed trailer, im using the +wire on my 7 way trailer connector to charge my battery. Theres 14.4v on the truck side of the connector but theres never more than 13v at the battery, do i have something wired wrong or is that normal. Thanks.

asked by: Shawn W

Expert Reply:

Since you are still getting 13V at the trailer battery, it's unlikely that the voltage drop is caused by any incorrect wiring connections. The voltage drop you are experiencing from the 7-Way on your vehicle to the trailer battery is instead likely due to the gauge of the wire itself that is being used.

To reduce this voltage drop, I recommend going to a thicker 10 gauge wire like # 10-1-1, which is sold by the foot. A thicker wire will result in less of a drop and will carry more current, which is what is actually charging the battery in your enclosed trailer.

expert reply by: Chris R