Do I Need a Battery Charge Line When Using Demco SBS Stay-IN-Play DUO Supplemental Braking System

Updated 02/06/2023 | Published 02/03/2023

Products Featured in This Question

Demco Stay-IN-Play Duo Flat Tow Brake System for RVs w/ Hydraulic Brakes - Proportional

(827)

$1245.50

Roadmaster Battery Charge Line Kit for Towed Vehicles

(1409)

$50.41

Roadmaster Battery Charge Line Kit for Motorhomes

(151)

$58.90

Roadmaster 7-Wire to 6-Wire Straight Cord Kit - 6-1/2' Long

(55)

$89.84

Question:

I have been getting estimates for installation of a flat-towing package on my 2006 Jeep Wrangler Sport including the Stay-IN-Play DUO supplemental braking system. Some of the installers are telling me I need battery charge lines in both the coach and the towed vehicle to trickle charge the towed vehicles battery because of the use of the towed vehicle battery by the Stay-IN-Play DUO supplemental braking systems vacuum actuator as well as the brake and running lights. Is this necessary for use of the Stay-N-Play DUO supplemental braking system?

asked by: Lyle W

Expert Reply:

It most cases, it's recommended to go ahead and install a trickle charger on the vehicle's battery while using a supplemental braking system like the Demco SBS Stay-IN-Play DUO Supplemental Braking System part # SM99251. In most cases, there is already a charge line run on the motorhome so in which case you'd just need the Roadmaster Battery Charge Line Kit for Towed Vehicles part # RM-156-25. If there is not a charge line on the motorhome then you'd also need the Roadmaster Battery Charge Line Kit for Tow Vehicles part # RM-156-75. The braking system pulls power from the vehicle battery so a charge line help prevent that battery from draining while in tow when it's not receiving a charge from the vehicle's alternator.

If you don't know whether or not the motorhome has a battery charge line, check the pins inside the trailer connector for one that is hot at all times and if you find one you'll know you have a battery charge line circuit run. In order to run said circuit from the tow vehicle to the towed vehicle we typically use a seven to six way umbilical like the Roadmaster 7-Wire to 6-Wire Straight Cord Kit part # RM-98146-7.

I also recommend talking a look in the owner's manual as there may be other guidelines to follow to ensure the towed vehicle's battery does not drain while in tow.

expert reply by: Conner L