Will SMI Stay-IN-Play DUO Drain Battery on 2006 Jeep Liberty While Flat Towing

Question:

Will this unit drain the towed battery? Is there a way to get power from the towing vehicle instead

asked by: Teo

Expert Reply:

Since the SMI Stay-IN-Play DUO Supplemental Braking System # SM99251 uses power from your 2006 Jeep Liberty's battery to engage the compressor, it is possible that the Stay-IN-Play could potentially drain the vehicle's battery over the course of a number of hours. We have not heard reports from our customers on this, but it is a possibility.

I was not able to find any known issues of the Liberty's battery being drained while in tow mode in the vehicle's owner's manual.

One thing that helps keep the towed vehicle's battery going is starting the vehicle and allowing it to run for several minutes while stopping to fuel your motor home or get a bite to eat. This gives the battery time to refresh before hooking up to be towed again.

Another solution is similar to what you mentioned, running a power wire from the motor home's battery to the Liberty's battery. This will not charge a dead vehicle battery but will offer a maintenance or trickle charge to help maintain the battery while the Liberty is being towed. To do this, you will need trailer connectors on each vehicle that allow you to connect a 12- or 10-gauge wire to corresponding pins. If your motor home has a 7-Way connector, it is likely that there is already 12V power on the pin in the 1 o'clock position. You can use a circuit tester # PTW2993 to see if there is constant power on this pin. Otherwise, you will want to use wire, such as # 10-1-1, to provide 12V power to this pin on your motor home's trailer socket.

On the Liberty, you will want to use at least a 6-Pin trailer connector so you can run the maintenance wire to the battery. A wiring kit like # RM-15267 will give you a 6-Way connector on the front of your vehicle. From the center pin on the 6-Way, you will want to run an additional length of # 10-1-1 wire to the positive terminal on your Liberty's battery. To connect the wire to the positive battery terminal you can use the Ring Terminal # 44-5356A.

If you don't already have them, the additional components needed to flat tow your 2006 Jeep Liberty:
Roadmaster EZ4 Base Plate Kit # RM-521423-4
Roadmaster Falcon 2 Tow Bar # RM-520
Roadmaster 68-inch Coiled Safety Cables # RM-643

I have also attached a couple of help articles on flat towing for you.