HDC - Hill Descent Control questions

Quote:

Originally Posted by rodjam

I agree with Connick.
I regularly do a very steep and windy descent into a valley.
With my Kimberley Kamper attached, weighing 1.8 t with water etc.
The first few times with hill descent, the brakes lit up after 10 mins and had to wait some time to cool sufficiently.
That's even with the electric brakes turned up.
After about 10 descents trying various settings tried manual low and engine braking...
Works much better IMO!
Without the van, hill des is fine.
Just my experience!

Is your trailer braking electric?

If so, is it proportional or time delay. If it's time delay, it might not be doing anything.

Most (I know nothing about yours) time delay units are connected to the brake light. Once the brake light comes on the brakes are applied at a set rate. The set rate is usually a dial on the side of the unit. While these units work well most of the time they are next to useless in an emergency as they dont know you are stopping faster and still come on at the same rate. Basicly once the brake light comes on the start applying and continue to full brake in the set time. The set time could be 10 seconds by which time you have already crashed in an emergency.

Also I dont know about LR but my Skoda doesn't activate the brake lights when HDC is working so I would have no trailer brakes with a time delay brake cotroller.

Most of what I have seen in Australia are time delay units. I suspect mainly due to the cost here. Hayman Reese want $250+ for their cheapest proportional unit compared to less than $170 for a time delay unit. Proportional units are far, far cheap OS and where mine (now my brothers) came from.

Proportional brake controllers have an accelerometer that monitors the rate of deaccelertation and applys the brakes accordingly. If you jump on the brakes hard in an emergency, the controller will apply full brakes as fast as possible. Like wise if you use a lower gear for engine braking down a hill the controller will apply a small amount of trailer brakes. These are irrelevant of if the vehicle brakes are applied or not. The aim is to have the controller set so as to not apply anymore vehicle brakes than as if no trailer was attached. All the extra weight of the trailer is braked by the trailer itself.

I did some research about electric brake controllers as my Skoda has a different stability program for when towing to the vehicle on it's own. I suspect LR has a similar thing in the D4 with the "Anit trailer sway". It's a requirement for any trailer over a certain weight in the UK to have break away trailer brakes, including electric so they have a battery mounted in thier trailers/caravans with a proportional brake controller which runs the trailer brakes. The whole system operates seperate to the to vehicle. If the vehicle breaks away the trailer will start to slow and the deaccelaration will cause the brakes to be applied which will cause it to slow faster which will cause more braking. I think it's a great system and something we should see more of here. All trailers over 750kgs in Australia require to be braked. If the brake controller is part of the trailer, any vehicle can tow it without the need for the tow vehicle to have a brake controller. Makes sense to me and it works far better than the time delay controllers the majority of people currently use.

Happy Days.

The LR HDC works in any gear (including reverse). It activates the brake lights, so will also activate your trailer brakes (if electric).

HDC has a certain amount of "intelligence", in that it controls each wheel independently. So whilst engine braking is an effective way to control downhill speed, and saves wear and tear on the braking system, on a very slippery downhill HDC will provide better braking whilst also keeping the vehicle on line.

Use it only when you need to.

Cheers,

Gordon

If the situation is bad enough, just using engine breaking can be useless. With an open diff, when one wheel is on a very slippery surface like mud and the opposing wheel has traction, the wheel on the slippery surface will spin in reverse while the other roles forward. Once it goes, it's much harder to stop.

I have used it in the Yeti and it's fantastic when you are on a very steep decline.

I know the Yeti brake lights aren't activated because I had a mate following and he commented that I didn't touch the brake pedal.

Happy Days.