Electric trailer brakes - for some inexplicable reason - is still not legal in South Arica.
It is however very popular in the USA and Australia.
If you ever had to tow heavy trailers, you will know that run-in brakes works well, but not without problems.
They often need adjustment before a trip to make sure the trailer stops, and does so smoothly without the snatch that often develops as the brake linings wore out.
The biggest disadvantage of run-in brakes is that if the trailer starts fishtailing, you cannot dare to step on the brakes. All you can do is accelerate out of the fishtail - IF you are lucky enough to have enough power left in the towing vehicle - or you can lift your foot from the pedal and cling to the steering wheel for dear life until enough speed is lost for the swing to stop.
Another big disadvantage is that run-in brakes does not work in reverse. This is no big deal on tar roads, but if you go real off-road then a trailer is a serious matter. It absolutely increase the risk to stall on an incline significantly and if the brakes does not follow the command of the brake pedal, be assured that you will have brown undies.
Electric brakes changed all that.
Because it can be activated without any force on the vehicle, a trailer with electric brakes can start braking with greater force than the vehicle and pull the vehicle back first before the vehicle brakes starts to do real work. It also works in reverse.
This gives a lot of reassurance because when you touch the brake pedal, you can immediately feel the trailer brakes actually works, and if it does not at least you have warning to change tack.
With electric trailer brakes, if the trailer starts fishtailing stability can immediately be restored by touching the brake pedal and allowing the trailer to pull on the vehicle. Simple as that and far safer than trying to power out of trouble.
OK, so I decided to go the electric brake route on my off road trailer many years ago and it I would go this route any day again.
There are many trailer brake controllers on the market, but I did not like either the functions and the fact that it is quite an intrusive installation on the dash.
One of the regulations of trailer brake controllers, is that it should be able to determine the brake force indepently from the vehicle system.
This can be interpreted many ways, but what it certainly means is that one cannot plumb into the hydraulic portion of the brake lines to install a sensor to determine brake force.
When I designed my electric brake controller, I wanted something small with multiple modes of operation.
Today, there are many versions of trailer brake controllers:
- The simplest is a ramp controller, which will simply ramp up the brake force when you touch the brake pedal. While it does require adjustment from the driver some times, this actually works quite well.
- The other versions today, determines the brake force with g-sensors. This also works well.
- Older versions that does not exist any more, had a brake position sensor on the brake pedal which created brake force directly proportional to your input - in my opinion it cannot get any better as it is 100% predictable.
I then designed my brake controller to have both an input for the brake position sensor and an automatic fallback to ramp force if the sensor fails.
The brake position sensor input works brilliant. The trailer feels like it is one with the car. I simply do not want any other method. Old, simple and it works.
Sadly I am not allowed to sell this controller for legal road use in South Africa.
That said. It is available for those who need it for other use and who can understand the advantages of this system.