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Posted

Hi guys

Just upgraded to new trailer with electric brakes. I I Had a Redarc brake controller fitted and when I plug trailer in the the light on brake controller glows green and changes to red when you brake as it should but after a while the light begins to fade like the battery is going flat. My question is why does it seem to be running off the emergency brake battery and draining it when it should be running off the car battery. Any help would be great.

Thanks Curly

Posted

Have you got power going to the plug from the car ??

Posted

Yes the is power to the brake controller because when there is no trailer plugged in the light on controller glows red when you brake.

Thanks Curly

Posted (edited)

I just did a quick search of the Redarc site... this is what they say regarding shade of red "Application of the brakes from the foot brake or the manual button on the controller will change the LED to red - the shade of red indicating to what degree the brakes are being applied."

Shade of red seems to be related to the braking gain you have set. Have you changed the braking level in-between application of the brakes??

http://www.redarc.com.au/products/product/remote-mount-electric-trailer-brake-controller/

Edited by zmk1962
Posted

Hi zmk1962

That's excactly what happens if the battery on the trailer is charged. When driving the brakes seem to be running off the trailer battery instead of the csae battery because after about 1/2 a hour of driving the brake indicators light starts to fade until the battery is flat then the brakes don't work.

I hope this make sense.

Posted

I don't have a Redarc system so can only go of my experience with my much older cobmination of Hayman Reese controller + Carlisle Hydrastar trailer brake unit. It sounds like your wiring between the Redarc in the car and the trailer is incorrect or incompatible or faulty. There seems to be a charging circuit from the vehicle to the trailer that is missing or in-operational. As I understand it, your trailer brakes should ONLY run off the trailer battery when the breakaway switch has been pulled out of its socket. During normal operation when the trailer is connected to the vehicle brake power is drawn from the vehicle -- it should not be running off the battery.

You said you recently installed a Redarc controller in the car, what is on the trailer? Is that a Redarc unit or wired to be compatible with your Redarc in car controller? Can you track down the wiring of the trailer?

In my case for 10yrs I ran with the flat 7pin connector between the car and trailer, but I had to upgrade my existing system to comply with RTA standards (namely in car monitoring of the trailer brake battery condition) and this forced an upgrade to the 12pin connectors to accommodate the additional charge and monitoring circuits that were required. As a first check what is on your car and trailer 7 or 12pins?

From memory in the past you were able to activate the trailer brakes and charge the trailer battery off your brake light signal in the car...but to meet the current requirements that are being enforced regarding monitoring the trailer battery condition from the normal driving position, you have to disconnect the charging while you were sampling the battery - otherwise you are just monitoring your vehicles charging circuit. This required a separate circuit to be installed just for charging the trailer battery - which could be isolated during sampling period. The operation of the trailer brakes when connected was still through the vehicle brake circuit (not from the trailer battery). The modern controllers like the Redarc may be expecting separated wiring, but your trailer may be wired differently. Hence why RTA now expects trailers to have a sticker that they must be towed by a vehicle with a "compatible system" and both must be presented as a set at rego time of the trailer.

Posted

I have attached a picture of the basic wiring for the connections. This was from -

http://www.4wdadventurers.com/showthread.php?775-DIY-Guide-to-Trailer-Plugs

The basic 7pin configuration is replicated in the 12pin configuration - and 12pin has additional pins like Pin 9 for Aux Battery charging. Pin 5 is the braking signal common to both.

But it sounds like you are replicating my old 7pin configuration - which was legal unless your rig is over 2T and has to go to a HVIS for rego (Heavy Vehicle Inspection Station) which required the in car monitoring of the trailer battery.

So if you have 7pin trailer and 7pin car then you are running only one circuit for the brakes - and this should be wired on the trailer to power both the brakes and to charge your trailer battery. (The battery charging will only occur when the car brakes are applied). Pin 5 is what your trailer brakes should be running off - and the car circuit feeding Pin 5 should be hardy enough to take the brake load of all the trailer brakes and the trailer battery charging. If you have just tapped into the car tail light to feed Pin 5 I doubt you will get enough current through pin 5 to drive the trailer brakes and charge the battery - you may have enough to activate the trailer brake controller but it may be drawing current from the trailer battery to do the actual work of powering the brakes.

Ideally Pin 5 should be supplied through a separate relay in the car activated by your brake circuit. Also ideally on the trailer - the brake battery charge circuit being fed from Pin 5 should have a diode (to only allow current flow one way into the battery) and not allow the battery to drive the trailer brakes - preserving its charge for emergency use.

Ofcourse there will be a separate circuit from the trailer battery through the breakaway switch to power the brakes in the event of a disconnection from the car in emergency.

Not sure if this is helping!

post-20634-0-06903700-1441963207_thumb.jpg

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