Watch Your Brake Controller!

[Old.Tony]

We've taken our new van out for its first overnight trip and learnt a couple of things that are quite important. I'd never noticed these with the lighter van, but then I was the one that had adjusted the brakes, and I hadn't manipulated the brake controller to mount a Brakesafe monitor.

In order to tow heavy, you need:

* Capacity to tow heavy. This means a vehicle that has the power, is rated for the tow and has enough available capacity in its GVM to take the ball weight without exceeding the vehicle's limit.

* Decent electric brake controller. I've used a couple of different ones, and far and above the best is the Tekonsha Prodigy P3. Read on for an issue we discovered with it!

* A Brakesafe monitor. NSW law requires anyone towing more than 2T to have a breakaway braking system and recently they introduced a law that the system is monitored in real time by the driver.

You should also consider (not necessarily just for heavy stuff):

* Weight distribution hitch suitable to the ball weight of the trailer
* Towing mirrors that comply with width regulations and give you the required visibility
* A rear vision camera that can be manually switched so that not only you can see behind you, but you can see where you're reversing to

Now for the fun I've had ... I mounted my RM6000 Breaksafe Monitor on top of my Prodigy P3. In order to keep it held tightly, I angled the Prodigy upwards, because the Prodigy can be mounted in any position.

That seems to have been a mistake, because returning the Prodigy to its former position (a change of only about 15 degrees) has removed the problem.

What happened? We crested a rise and saw a tight bend at the bottom of the hill we were starting to descend, so my foot naturally went to the brake and held it lightly as I controlled the rate of descent.

Suddenly, BANG and the wheels on the caravan locked up, I noticed that the Prodigy was pumping 12A out the back and I let go of the brake. I lightly touched the brake - enough to bring on the brake lights, but no pressure on the brake pads - instant 12A to the trailer again. It seems that the increased angle caused the Prodigy to dump full current at the trailer. We're lucky that we were travelling in a straight line!

Has anyone else experienced this?

I started writing a FAQ on towing, I think I'll get it finished with the new laws for NSW and post it!

 

[nathand22]

I could be wrong Tony but i have a feeling that i read in the P3's instructions that the unit must be set up at a certain angle and then maintained at that angle, i think it said it had something to do with knowing what angle the car is at and something to do with preventing rollover or if the trailer were to roll over??? im not sure really, so i will read the book and get back to you, it may of even been on the little DVD the unit come with.......... i will find it and check.

 

[doc]

Hey Tony,

We run a P2 - same unit as yours, but we miss out on the additional diagnostic features of the P3.

Anywho...I had cause to change the installation place of my P2. Where it was originally installed it was on quite a steep angle, whereas now its quite flat. Previously, on steep downhills, I experienced the same as you - van brakes would come on HARD. And in the storage yard, this little downhill pinch where we swing down to store the van, it would lock up the wheels on the gravel.

Since moving to the new possie, no probs at all. Application of brakes is much more progressive.

Not sure about resetting the controller or anything like that, but the pendulum/whatever it is that helps determine progressive braking seems to behave better for us when the controller is mounted flatter.

I've got another theory, but its just that - a theory - no proof. When going down steel hills, we actually WANT higher brake application than same speed on the flat. So the controller delivers. But with the controller mounted at a steeper angle, it gets sort of confused and thinks the hill is steeper than it is. And bang - brakes slam on.

I've been using the boost function - you might want to consider it. I have found with my current adjustment on the voltage, that boost setting 1 works brilliantly on the highway, then when I get into town I just turn boost off and everything is peachy. One button.

 

[Old.Tony]

I had to turn the boost setting off, and add "relax brake adjustment" to the new van's first service checklist. On the old van, I had adjusted the brakes myself, and boost off was perfect for mud, boost 1 for wet dirt+gravel, boost 2 for dry dirt/gravel, boost 3 for highway. I want it that way again!

I've had no trouble since I angled it back the way it used to be - so your theory does sound right. It's supposed to be completely automatic - so I might take mine apart in case there's a problem with the circuit. I won't be towing again for a couple of weeks at least so I've plenty of time to tinker and I think my Prodigy's out of warranty now, so if I repair a cold solder joint or two, nobody's going to start bitching at me about it!

I don't like hearing the wheels sliding when I'm going down a steep hill in the wet. Oh, that does NOT make me a happy lad at all.