Regarding disadvantages of various trailer brake methods:
The Electric-Over-Hydraulic (EOH) brake actuators generally require a 12-Volt high-current circuit be provided to the trailer from the towing vehicle to operate the electric motor for the hydraulic pump and a local battery as back-up. This local battery on the trailer is required so that the trailer brakes can be actuated if the trailer breaks away from the towing vehicle and the 12-Volt circuit from the towing vehicle is broken.
The local battery charge is typically maintained by a local battery charger that gets its primary power from the 12-Volt circuit high-current circuit from the towing vehicle.
Of course, the local battery needs a battery box to contain the battery.
To prevent theft, the battery box should have a locking system.
And EOH brakes require an electrical switch with lanyard to actuate the local battery to run the pump to apply the brakes if the trailer brakes away.
Of course, the trailer still requires a hitch coupler. Actually, finding a good hitch coupler for a boat trailer with a single center trailer frame element without a surge brake actuator is a bit harder than finding one with a surge brake actuator. Many of the non-surge brake actuators are made for trailer frames that joint to frame elements into a vee at the hitch.
In summary, for a boat trailer with a single channel beam element at the hitch, for electric-over-hydraulic brakes you must install at the front of the trailer :
- a new hitch coupler without surge brakes
- a new trailer electrical fitting with the 7-pole standard plug
- an electric-hydraulic pump brake actuator
- a breakaway 12-Volt battery of about 10-Ampere-hour capacity
- a battery box with lock
- a battery charger, and
- a break away electrical switch with lanyard to detect the break away from the towing vehicle and operates the brake actuator pump
A "breakaway kit" with battery box, charger, battery, and breakaway switch is about $90. For periodic replacement. a typical 10-Ampere-hour lead-acid 12-Volt battery will weigh about 7-lbs and cost about $55. Figure the weight for all at 10-lbs.
A Dexter DX Series Electric Over Hydraulic Brake Actuator for Disc Brakes rated for 1,600-PSI costs about $800 and weighs 30-lbs.
A Titan straight tongue 2-5/16-inch-ball 3-inch channel coupler costs about $200. The weight will about the same as a surge coupler.
A quick total of cost of parts gives a figure of about $1,100 for EOH brake re-fit. The added weight compared to the surge coupler is about 40-lbs.
As a result of adding all of those components, a system of EOH brakes will add considerable weight to the trailer--and at the worst place, the tongue. Tongue weight is generally the limiting factor in many towing situations because most of the tongue weight is borne by rear axle of the towing vehicle. If tongue weight becomes too high, the boat position on the trailer may have to be moved aft to reduce the tongue weight contributed by the boat weight.
The rear axle weight load can become surprising close to the axle weight rating limit when tongue weight is high. Upon the first weighing of my boat, trailer, and towing vehicle (a 7,000-lbs tow-rating GMC truck,) I discovered
the rear axle load was only 88-lbs below the maximum rated load, which was surprising because the boat and trailer together were only 5,600-lbs, or 80-percent of the towed weight rating. I subsequently moved the boat farther back on the trailer to reduce tongue weight from 520-lbs to
In additional to the added components to the trailer, the towing vehicle must also have the following provisions:
- a 7-pole trailer connector; in many instances this is not always provided in the towing vehicle unless a special towing package was ordered
- a 40-Ampere fused circuit running into that 7-pole connector; in many instances this is not always provided in the towing vehicle unless a special towing package was ordered, but may be available with addition of a fuse (best case) or connecting loose conductors in the harness at each end (less than the best case); and,
- an electric brake proportional actuator mechanism.
In summary, the conversion of an existing boat trailer and the typical towing vehicle with the common flat-four or perhaps flat-five socket at the hitch to accommodate electric-over-hydraulic brakes is not simple, quick, and inexpensive.