A New RVer reader asks, “I’ve been looking into buying a travel trailer for taking my family camping. I keep running into information about brake controllers. I’ve towed boats on trailers for years without any such thing as a brake controller; what gives? And how do they work, anyway?”
Smaller boat trailers with typically light loads don’t usually require trailer brakes. As your boat (and trailer) get bigger, you’ll probably find a braking system that’s hydraulically activated by a so-called “surge system.” Step on the tow vehicle brakes and as the boat trailer pushes forward against the hitch, the pressure actuates a hydraulic system that applies drum or disc brakes on the boat trailer.
By nature, travel trailers tend to be heavier than a similar-sized boat. While you may find a few RVs with surge brakes, most have electrically controlled brakes. Simply explained: Inside the brake drum is an electromagnet attached to an actuating arm. When an electrical voltage is supplied to the magnet, it is drawn toward the moving metal brake drum. That movement forces the actuating arm to push the brake shoes out against the brake drum. Friction between the shoes and drum does the rest – slowing or stopping the rig.
In theory, just hooking the trailer brake electric wiring to the stop light circuit would force the brake shoes to push out against the drums. The problem with that is that it’s like only SLAMMING the brakes down on your car, rather than using a controlled “right amount of force” to slow down to stop. Locking up the brakes of a trailer is a dangerous way to try and stop a trailer while keeping it under control.
Enter the handy brake controller. This device applies a graduated amount of current to the brake magnets, rather than an “all or nothing” approach. Simply speaking, the harder you step on the brakes of the tow vehicle, the more voltage is supplied to the trailer brake system, and correspondingly the more braking power is applied.