Best Way To Charge A Breakaway Battery and a Winch Battery

Question:

I have a car trailer with a upg 42911 breakaway switch. I am trying to wire an s5000 superwinch as in your video but would also like to charge the grp 27 winch battery at the same time as I charge the small breakaway battery. I am using a 7 prong plug from a 2011 silverado. It is connected as in your video with prodigy p2. Can you advise me on what I need to do? Thank You,

asked by: Dan L

Expert Reply:

Using the breakaway battery charger to charge another battery on the trailer is not recommended. The larger battery you are using to operate the trailer winch would take an extremely long time to charge with a breakaway charger and would likely never charge fully with the limited amount of time the trailer is connected to the vehicle, even if towing long distances. The breakaway battery may not be charged sufficiently in this situation either.

The best bet for charging the winch battery is to use a 120 volt battery charger like the CTEK MULTI US 7002 12-Volt Universal Battery Charger w/ Pulse Maintenance, item # CTEK56353, before towing the trailer. Then, connect the power wire from the 7-Way connector on the trailer to the positive post of the winch battery. A ground wire will need to be attached to the trailer frame from the winch battery negative post also. The vehicle charging system will then help maintain the charge on the winch battery while the vehicle is running.

There is really no good way to charge a large battery on a trailer from the vehicle charging system, due to the vehicle system limitations and the wire sizes that are used to power trailer connection accessories, but the connector power source will help to keep the batteries topped off while towing.

expert reply by: Jameson C