I have a 2007 Dodge Ram 2500 Diesel that I tow a Circle J gooseneck 3h, slant load, with mid-tack and dressing area.

I have towed lots of boats, but am new to horse trailers.

The trailer dealer installed my B&W turn over hitch and the brake controller, and I've been been hauling wiith out any problems. I know the trailer brakes and controller work fine.

I was looking over the trailer today and found a small "motorcycle" sized battery mounted in a box near the goose neck pillar. It is not connected. What is this battery for? I assume it must be the electrical supply for the break away switch on the trailer brakes... if so, how does this get charged? If now, what is it? If it is not charged will the brakes lock?

Thanks... I've seen lots of great info in the forum!

Welcome to the forum... You are correct. The battery is the power supply to the brakes if the trailer were to break away from the tow vehicle. It may be a dry cell battery or it could be a wet cell battery that is charged from the vehicle. Either way it should be wired to power the trailer brakes when the break-away switch's lanyard is pulled.