People often ask us “how is it possible to draw enough amps from standard trailer wiring to power electric trailer brakes?”. Until the invention of Elecbrakes, a common assumption was that a trailer side power supply configuration was not possible.
It’s this kind of thinking that has seen electric brake controllers stuck in the same rut for too long. This meant no choice for users except costly tow vehicle modifications. Elecbrakes has changed everything.
This article will explain the following:
- The basics of electric brake controllers:
- How conventional controllers operate:
- How Elecbrakes draws sufficient power from standard trailer looms to operate electric brakes:
1. The basics of electric brake controllers:
What is an electric brake controller?
An electric brake controller manages the amount of electrical current (amps) that reach the trailer brakes from the car’s battery. This determines the power and timing of brake activation. The controller takes the current from the car battery and controls the flow of this power to the brake magnets on the trailer wheel hubs.
Brake controllers, just like vehicles, come in either 12-volt or 24-volt varieties and need to match the power source of the towing vehicle. Most conventional controllers are compatible with either 12-volt or 24-volt systems, but not both. Elecbrakes ensures maximum compatibility by working with either 12 or 24-volt tow vehicles.
Can I tow a trailer with electric brakes without an electric brake controller?
No. Without an electric brake controller the electric brakes on your trailer will remain inactive. This would put you in breach of the road rules in any state or territory of Australia. Unless you were towing a load with a GTM below 750kg. This means that for towing any load beyond a basic box trailer it’s crucial that you have trailer brakes. Especially when towing a load above GTM 2,000kg. In this case, it’s mandatory that these brakes are electric with a compliant electric brake controller fitted. Elecbrakes allows a trailer to comply with ADR38/05 and VSB1 for towing loads up to a GTM of 4,500kg.
What gauge wire for electric trailer brakes?
There is a range of wire sizes available for trailer circuits and electric brake wiring. When comparing wire thickness, a smaller gauge number represents a thicker wire. Even with a standard minimum of 16 gauge cables used in some trailer circuits, Elecbrakes functions correctly. It would not overload the wire and cause excess heating as 16 gauge wire has a recommended allowable ampacity of 15 amps. This is only slightly under a maximum brake load of 16 amps.
Keep in mind, this is a bare minimum and we would recommend at least a 14 gauge wire thickness. The National Electrical Code rates 14 gauge wire as providing an allowable ampacity for 20 amps of current at 30 degrees ambient temperature. This more than covers the power draw of Elecbrakes.
2. How conventional controllers operate:
How do other electric brake controllers work?
In older controllers, the power provided to the trailer brakes is supplied through a separate cable. With this setup, a power cable runs from the battery to the dash mounted or engine bay mounted controller. A control cable then runs all the way through the vehicle to the trailer connector and then onwards to the trailer brakes. The controls to regulate the trailer brake amperage are hard mounted into the dashboard of the tow vehicle. This necessitates interior modifications and locks the vehicle and trailer into a mutually exclusive relationship.
How much power do electric brakes use?
While there is no absolute standard for amp requirements on trailer brakes there are common practices between trailer component manufacturers. This creates a defacto standard. We’ve determined amperage requirements based on extensive testing, customer experience and information gathered directly from trailer component manufacturers. We’ve found the most common amperage draw on a 7-inch brake magnet to be 3.2 amps maximum. The increased amperage of a 10 or 12-inch brake magnet tends to max out at 4 amps. This means that a double axle brake system would be drawing a maximum of 16 amps for a full emergency stop.
How many amps does a brake controller draw?
A common misconception is that a 10 amp circuit is connected to a load that draws a full 10 amps. The reality is that the actual load is much less than the capacity.
A trailer-mounted Elecbrakes solution will draw up to a maximum of 16 amps of current from the car battery. The amperage is delivered through the standard trailer power circuits. This provides ease of installation and the revolutionary ability to tow a braked trailer with any compatible vehicle. All you need is the our wireless remote for in-vehicle brake response modification.
For those wanting to install the system on a tri axle trailer, Elecbrakes is fully compatible with an auxiliary power circuit. Auxiliary power is supplied by compatible vehicles through a 7 pin, 12 pin or Anderson plug with at least a 30 amp rating. An auxiliary circuit can also be used on a single or double axle trailer. This would remove the need to keep the tow vehicle’s headlights on while Elecbrakes is in use.
3. How Elecbrakes draws sufficient power from standard trailer looms to operate electric brakes:
Elecbrakes does things differently. One of its key features is the fact that it’s only mounted to the trailer. This provides the trailer user with the freedom of swapping out their ride for any appropriate tow vehicle, without costly modifications. But it also means that without wiring in a separate cable to the car battery all the power that is used to activate the trailer brakes has to be drawn from the existing trailer circuits.
Circuits already present in trailers for powering standard loads including tail lights, blinkers and brake lights each have a capacity of 10 amps. We found that while the maximum capacity on these circuits was 10 amps, the actual amperage used by each load only reached an average of 2 amps. This excess capacity is one of the secrets to Elecbrakes’ innovative power model.
Braking is triggered by a positive voltage being applied to the brake light circuit. Once braking is triggered, Elecbrakes uses microprocessors and accelerometers to measure, calculate and adjust brake response over 1000 times per second with a regulation resolution of better than 0.005amps (i.e. 16amps / 4095 discrete steps). This response matches the driver’s braking action on the tow vehicle and can be adjusted using the in-car remote for a fine-tuned proportional brake controller experience.
The smart controller inside Elecbrakes reads the excess amperage available in the tail light and brake light circuit, thousands of times each second. Based on this data the Elecbrakes software requisitions up to 8 amps of spare electricity per circuit, forming a total of 16 amps of available current for use by the electric brake magnets. Drawing power in this way from the tail and brake light circuits ensures sufficient power is available for up to 2 braked axles.
Elecbrakes’ use of standard trailer wiring makes towing better
As you can see from the above data, we have gone above and beyond to engineer the Elecbrakes proportional braking solution in such a way that it can be used in the widest possible range of circumstances. Elecbrakes has been embraced by trailer uses across Australia and the world, looking for a safe, flexible, multi tow-vehicle friendly system that can be installed in as little as ten minutes.
Thanks to the smart software engineering that powers every Elecbrakes system we have achieved a revolutionary efficiency in the way our electric brake controller is powered. This means that Elecbrakes is able to provide sufficient amperage to the brake magnets in an electric brake system using only standard trailer wiring, without the need for hard wiring into the tow vehicle. This has enabled Elecbrakes to offer trailer users a whole new way to tow, potentially saving thousands of dollars in unnecessary tow-vehicle installations over the lifetime of a trailer.