Is it Necessary To Ground a Trailer Mounted Auxiliary Battery To Trailer Frame

Updated 03/07/2012 | Published 03/05/2012

Question:

I have a utility trailer on which I have installed a separate battery to power a winch. Right now the battery/winch system is floating, not connected to the trailer frame. Since the trailer is grounded to the vehicle through the lighting system Im worried that if I ground the winch system to the trailer frame I may create a ground loop situation between the two batteries trailer and vehicle. Is there any downside to leaving the winch system floating and separate from the trailer/vehicle ground? Thanks fr your help.

asked by: Ray W

Expert Reply:

The way you currently have the system set up will work just fine for you.

However, if you want to use the 12-volt accessory feed from your 7-way to maintain (not charge) the trailer mounted winch battery, the battery would indeed need to be grounded to the trailer frame. This is a very commonly found set-up, you would not need to worry about any problems between the vehicle and trailer battery.

If the accessory circuit is used to maintain the battery, I would recommend installing a battery isolator, like part # PK5231201. The isolator will power down the accessory circuit once the ignition is shut off, so the vehicle battery will not become accidentally discharged.

We have an FAQ article about wiring electric winches that you might find helpful, see the provided link.

expert reply by: Mike L