Thursday, Jun 01, 2006 at 23:47
Doug, I measured the current the electromagnets take, its 4 amps each wheel when fully on. So, for a dual axle job, your wire and connectors have to pass 16A comfortably or you loose some braking power.
Also, Ray mentioned above that electric brakes do not work when stationary or in reverse. NOT true, the electromagnet activates the brake shoes in both cases. When stationary, the wheel might have to rotate 1/2 turn before the brakes lock up - and they WILL stay locked as long as there is sufficient current to the electromagnets.
Of course, your hand brake is usually NOT wired in to activate the trailer brakes but that could be done as most handbrakes have a switch that illuminateds a light on the dash.
What might not work in reverse is the controller, if its ONLY pendulum activated. I'm sure there is some way to override that on modern controllers ( I'm using a
home built controller). Perhaps some early controllers only had a pendulum, where the not working in reverse myth originated. Having only a pendulum activation is a bad idea as the trailer brakes then could never come on before the car starts to slow down. On wet roads you really want the trailer to slow down first or you could just as
well forget about electric brakes and install a simple override brake system.
You ought to, before embarking on a long trip, jack up each trailer wheel in turn and give it a spin after which somebody steps on the brake pedal. You should hear a 'click' and the wheel locking up instantly. Try that also in reverse, just to prove my point above. You hear another 'click' when the pedal is released, there is no 'hum' as somebody had suggested. I would not be happy with a controller that does not pass this
test.
BTW, here in WA electric trailer brakes have to be controllable from the driver while underway, which means the control box needs to be on or near the dash somewhere. It is beyond me why somebody would want to install it elsewhere.
Klaus
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