Towed Vehicle Battery Charge Line Kit for Demco Air Force One and Stay-IN-Play Duo Braking Systems

Updated 07/09/2026 | Published 07/01/2026

Question:

How does this trickle charge your battery, because it does not actually have a trickle charger on it. All it is doing is putting 12v power to the battery from the coach. Towed Vehicle Battery Charge Line Kit for Demco Air Force One and Stay-IN-Play Duo Braking Systems Part Number: DM66VR

asked by: Brian H

Expert Reply:

Hi Brian,

Thanks for your question, and I apologize for the confusion.

You are correct that the Towed Vehicle Battery Charge Line Kit for Demco Air Force One and Stay-IN-Play Duo Braking Systems # DM66VR is not a trickle charger.

What this kit actually does is help maintain the towed vehicle's battery by providing a 12-volt charge line from the motorhome's electrical system. While you're driving, the motorhome's alternator supplies power through the charge line to the towed vehicle's battery, helping offset the electrical draw from the braking system and other accessories. I think folks use the term trickle and maintain interchangeably here. The motorhome alternator by itself is not going to be able to "charge" a battery from a low or empty state so this is not a traditional battery charger either.

It looks like you may have just gotten a new Jeep Wrangler and are adding some flat tow components. Any big trips planned?

expert reply by: Christopher H

Sidney

7/8/2026

Just get one. Your toad battery will never be dead after a day of driving.

Mike

7/8/2026

@Sidney What he said

Christopher H.

7/9/2026

@Sidney What's your current flat tow setup?

Steve K.

7/8/2026

The charge line setup does work. I wanted more control and added an RVi Towed Vehicle battery charger with dedicated fused feed from motorhome battery. That has battery and state charge status indication and charges as needed.