electric brake controllers?

[meburdick]

Gotta love their "FAQ"

Apparently they didn't get the memo that electrons travel at 186,000mi/sec, so as long as they had heavy enough wire to handle the amp draw and they aren't daisy chaining the magnets (ie: the output of one magnet goes to the input of the next) it doesn't matter (within reason) how long the wires going to the magnets are or how much difference there is in wire length.

Aaron Z

Actually, electricity does not flow at the speed of light. It's MUCH slower. It's more on the order of 8-9 centimeters PER HOUR.

Wire lengths DO matter, but only if you're working with differences in length that are significant. Over a 30' run of wire, a few feet of difference is not even measurable. As long as all of the wiring is the same gauge, and the lengths are all within 10-15% of each other, there is zero measurable difference in how quickly a brake will react.

 

[meburdick]

Because it makes it a pain in the *** to maneuver your trailer, that's why!

It's usually counter-productive to have your trailer brakes activating when reversing. Your truck should easily be able to handle all the braking needs for reversing which you probably do at no more than 10 MPH. If it can't, how are you going to stop your rig if it's going forward down the highway at 60 MPH and the trailer brakes stop working?

i agree.. I was trying to back my trailer into a loading bay and the shop yard was gravel, and the bay was 1' wider than the trailer. stepping on the brakes made the brakes grab more int he gravel on one sid ethen the other making me go in crooked till I realized I still had brakes dialed in on my drawtight. once I zero'd brakes I got in in 1 try like normal. for a moment I thought I had forgotten how to back a trailer.. was kinda embarrising witht eh guys at the loading dock wondering why I couldn't get the trailer in like i did all the time..

With a straight time-delay controller, I could see where this would be huge pain. My P3 works with inertia sensors to control how MUCH brake force is applied, and I always set the brake force for the load on the trailer. So, I haven't gotten bitten by that sort of scenario (at least, not yet).

 

[aczlan]

Actually, electricity does not flow at the speed of light. It's MUCH slower. It's more on the order of 8-9 centimeters PER HOUR.
Wire lengths DO matter, but only if you're working with differences in length that are significant. Over a 30' run of wire, a few feet of difference is not even measurable. As long as all of the wiring is the same gauge, and the lengths are all within 10-15% of each other, there is zero measurable difference in how quickly a brake will react.

Odd, everything I have read (including a wiki article that I looked at to double-check) says that on uninsulated copper wire, electrons flow at over 90% of the speed of light... Otherwise computers flat out wouldnt work.

Aaron Z

 

[crazyal]

Just out of curiosity has anyone ever seen or heard of a cheap brake controller failing? I have heard of plugs falling out and one friend shorting a brake wire to ground (but it was designed with short protection so it didn't hurt it) but none actually failing. I'm wondering how often it happens?

I bought my P2 years ago and I bought it because I like the feature of not having to adjust it when it stop and go traffic. I hate messing with hydraulic lines, I always make a big mess, otherwise I would look at the Max unit to see what extra benefits it offered. But I also have a basic unit that had worked every time I needed and would still be in use today. I bet it cost $25 back in the day. It was only replaced because I got a three axle equipment trailer and I wasn't sure if it was able to do more than 2 axles.

 

[meburdick]

Odd, everything I have read (including a wiki article that I looked at to double-check) says that on uninsulated copper wire, electrons flow at over 90% of the speed of light... Otherwise computers flat out wouldnt work.

Electrons are not electricity. Electrons, in a vacuum, travel at essentially the speed of light. When those electrons are "stacked up" on/in a wire in the form of electricity, they bounce all over the place and crash into other electrons. The resultant "speed" that they move from one end of the wire to the other is significantly reduced.

Just out of curiosity has anyone ever seen or heard of a cheap brake controller failing? I have heard of plugs falling out and one friend shorting a brake wire to ground (but it was designed with short protection so it didn't hurt it) but none actually failing. I'm wondering how often it happens?

I bought my P2 years ago and I bought it because I like the feature of not having to adjust it when it stop and go traffic. I hate messing with hydraulic lines, I always make a big mess, otherwise I would look at the Max unit to see what extra benefits it offered. But I also have a basic unit that had worked every time I needed and would still be in use today. I bet it cost $25 back in the day. It was only replaced because I got a three axle equipment trailer and I wasn't sure if it was able to do more than 2 axles.

Law of diminishing returns... If you can accomplish 99.999% of the jobs for cost "X", why would you spend "3X"? For the "average" person, the standard units like we're discussing here for $100 or so will do the job every time.

 

[meburdick]

Think about it this way...

You have a 100' hose that holds an exact number of drops of water when "full". The hose is currently full.

You add water to one end of the hose at the rate of one drop per second.

How long does it take for any one specific drop of water to travel through the hose and come out the other end?

Similarly, how long will it take for *ANY* drop of water to come out the other end as you add a drop to one end?

The difference in these answers is the difference between the flow of electrons through wire and the "speed" of electricity.

 

[aczlan]

Electrons are not electricity. Electrons, in a vacuum, travel at essentially the speed of light. When those electrons are "stacked up" on/in a wire in the form of electricity, they bounce all over the place and crash into other electrons. The resultant "speed" that they move from one end of the wire to the other is significantly reduced.

As I understand it, the electrons are like standing water in a pressurized firehose. When you open the valve, the exact molecule that you send out may take a little bit to come out, but you will get have 1 electron out the other end of the wire with a delay of ~the speed of light from when you send 1 in.

Aaron Z

 

[Diamondpilot]

I have seen as many of brand X fail as brand Y. Its usually just a simple matter of them not powering up and most of the time I get them they have been installed improperly.

I have had the same Reese Tow Master Timed unit in 5 different F-150's, a Mountaineer, and now my Titan. It has to be 15 years old. Never a hiccup.

Chris

 

[aczlan]

Think about it this way...
You have a 100' hose that holds an exact number of drops of water when "full". The hose is currently full.
You add water to one end of the hose at the rate of one drop per second.
How long does it take for any one specific drop of water to travel through the hose and come out the other end?
Similarly, how long will it take for *ANY* drop of water to come out the other end as you add a drop to one end?
The difference in these answers is the difference between the flow of electrons through wire and the "speed" of electricity.

True, but my point was that the length of wire (within a reasonable difference of 2-15 feet as could be seen in a trailer brake connection) will not make any appreciable difference of how fast the trailer brakes are applied (assuming that the wires are sized properly).

Aaron Z

 

[not2old]

Just out of curiosity has anyone ever seen or heard of a cheap brake controller failing? I have heard of plugs falling out and one friend shorting a brake wire to ground (but it was designed with short protection so it didn't hurt it) but none actually failing. I'm wondering how often it happens?

I keep everything until it quits. The original controller I put in my 1990 F250 quit and was replaced about four years ago. The controller in my 1991 F250 did the same a year later. I've never really been happy since I got rid of my previous truck which was plumbed into hydraulic brake pressure to determine braking force. After reading this thread I'm going to look into some of the better units which I wasn't aware of until now. I'm never over 18,000# gross combined.