How to Charge a Flat Towed Vehicle's Battery That Uses Wireless Lights
Updated 01/27/2026 | Published 12/31/2025
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Question:
OK.. a little electrical help needed. Bought a new to me F-150 hybrid. 4x4 and does have the TOAD mode. Im trying to figure out the best easiest and cheapest way to send power to the TOAD battery directly to the TOAD. I dont use the 7 Way plug as I use wireless trailer lights. BUT the hybrid does keep my back lights on when in toad mode, using the patriot 3 so there is a drain on my battery. At first I thought maybe all I needed was a direct 12vlt wire from the RV to the TOAD, but from reading, most say I should put some kind of Charger in between. do I really need something in between.. I thought that the power from the RV battery would maintain the TOAD. If I do need something, what do you recommend?
asked by: Joseph H
Expert Reply:
Hey Joe. To charge your F-150's battery while flat towing, you'll need to add a battery charge line kit item # RM-156-25. It's going to connect directly to your truck's battery and has a 15 amp circuit breaker included. You'll wire this directly to the 12v circuit on your motorhome's 7-Way connector.
The only additional thing you could add is the Roadmaster Single Park Light Diode item # RM-690. It'll prevent any electrical charge from back feeding to your motorhome. Other than that the item # RM-156-25 includes all you'll need to keep your F-150's battery charged up will you're traveling. I threw in a couple of installation video links below, we did on F-150's, so you can see how to get the charge line installed.
This setup will require the trailer connector on your motorhome to have an active 12 volt battery charge pin too. Most of the time this isn't a problem on the motorhome side, but if you find that the battery isn't charging or that you don't have power on the 11 o'clock pin in your motorhome's trailer connector, then you will also want to install the the charge line kit for motorhomes, item # RM-156-75.
The Blue Ox Patriot item # BLU37TR is a great choice for your F-150 and it is compatible with the hybrid models. Did you have any issues powering it? I know they're going away with cigarette lighters in the newer vehicles.
You can add this information, along with any other questions you have, where it says Reply to Jerred H.
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Roadmaster Battery Charge Line Kit for Towed Vehicles
- Accessories and Parts
- Flat Tow Wiring Harness
- Battery Charge Line Kit
- Roadmaster
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Jerred H.
1/27/2026
Hey Joe, how did things go with the Roadmaster charge line kit on your F-150 hybrid? Did it keep your battery topped off while using the Patriot 3 brake system? Your update could make it easier for others setting up a similar flat tow setup.