brake controller output

[kaninyeg]

I have a 2012 Ford F250 with the integrated brake controller.
It does not seem to work as well as it did when new. Cannot lock the brakes anymore. (same trailer)
Ford says controller checks out fine. Trailer place adjusted my brakes to the point that they are almost dragging.

When you adjust the controller from a 5.0 to a 10.0 what changes to give more braking power. I had assumed that the AMPS would increase to send more power to the magnets but the output measured by both Ford Dealer and Trailer place stayed at 10 to 11 amps for all settings. Ford had nothing in their repair manuals about what the AMPs should be.

Does anyone know what a normal AMP output for the various brake settings should be?

[marininn]

thanks. wiring is not the issue. There are just two wires that are hard to mess up, unless the wiring is shorted to itself there is nothing left there. I did put new wire in, bypassing the trailer wiring, I put two wires at the plug and went straight to the brakes. 4.x volts, but no action at the brakes. Is 4volts enough? 5 is supposed to be the max it puts out.
I tested magnets individually and one worked fine and made the brake work, another did not work - just made a whining noise, did not test the other two, gave up and ordered 4 new magnets. we will see…

[BenK]

ops...those links no longer work...these do...

LAdams article on rewiring his trailer brakes
LAdamstrailerbrake trailerbrakeharness trailerbrakewiring rewiring


Jbarca's write-up
http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/23458294/gotomsg/23459585.cfm#23459585

[BenK]

Better to replace the whole trailer brake wiring and here is a link to the best article
on this portal and reminds me how much missing Les Adams...

You most likely will end up with a Hodge-pog wiring system that will cost more
both in time and money and still not have as good a harness vs replacing the
whole thing in the first place

Wiring Electric brakes
Ladamstrailerbrake trailerbrakeharness trailerbrakewiring

[marininn]

Anybody know. Was my assumption right?
I am having trouble with my trailer brakes. There are 4. I know the controller worked on a friends trailer with 2 brakes. I tested at the hitch and get almost 6 volts at full over-ride position. I will not give 12 volts.
In the trailer I get a little less.
There is nothing happening at the brakes, no click, nothing.
I re-did the wiring connections, cutting the old and connecting wires on freshly exposed copper.
I don't think the brakes have ever been used in 20 years, previous owner did not have controller.
Pads look new except for dirt.
I cut trailer cord and wired on a new 7-pin connector.
Wiring goes - blue wire to black wire from brakes. white/ground from vehicle goes to common ground in trailer (including coach battery). White wire from brake goes to this common ground.
I have tested things with coach battery connected and not connected…
At this point I have to start replacing things. What should I look for first?

[kaninyeg]

thanks for all the replies.
The brakes on the trailer are fine. I had the bearings repacked the drums and shoes inspected, each wheel was adjusted to the point that the shoes were just starting to drag.

Both the trailer brake place and the Ford dealer had a testing box which they hooked up the trailer plug on the truck. When the brake controller was activated manually with a setting of 5.0 and then the max of 10.0 both boxes recorded the same thing, 12 volts and 11 amps for both settings. The Ford repair manual states the system is working if it puts out 12 volts, no mention of AMPs. So if you get the same readings for all settings how do you get stronger braking by increasing the number on the brake controller. What am I missing?

[BenK]

marininn wrote:
BenK, i think they are talking about voltage, not ABS.
From what I surmise, the on and off pattern of the brake controller is not for ABS, I was not thinking that, but for voltage. Sounds like the brake controller puts out the full 12 volts, but when it cycles on and off quickly it roughly equates to a lower voltage. Am I correct here?

The PWM will simulate a constant voltage (RMS) and the inductance of
the magnet will smooth it some more (hysteresis)

So, 50% on 50% off time-wise yields a kind of dirty 6 volts (is what I assume). This happens too fast for the mechanical brakes to respond to, so the effect happens at the brake (the spring, pad and magnet).

See below comments and is the inertia/RMS voltage

If I understand… The brakes are powered by the movement of the wheel. The brake drum rotates around the stationary brake pad. The magnet pushes the pad into the drum and friction pulls the pad, or wedges it almost, into the braking action. Compared to the electronics on the other end, this is a slow process.
Someone add to this as is all I understand so far…

Yup, the inertia in comments below

Sorry, am also answering a PM thinking PWM'ing the signal to the
trailer is a form of ABS

ABS...Anti-Lock Braking System and is to keep the tires from skidding by
NOT holding their rotation at the point to skid

Not stopping rotation, just slow the rotation down enough to keep the
tires from skidding. This is part of what is meant by modulation of
the braking

Today's ABS will reduce the MC Hydraulic PSI sent to the calipers many
times per second...buzz them with reduced PSI and then back to high PSI
Pulses per second and as for how many per second you'll have to look that up

There is a rotation sensor on each wheel and is basically a gear toothed
ring, but many call it the tone ring



NOTE: this is why when changing tire rev's per mile...you must or should
tell the computer(s) of that change, as they do NOT really sense skid
but look up on their tables for 'that' tire's rev's per mile vs the
MPH you are going...AKA changing tire size/type/class/etc...gotta
tell (reprogram) the computer(s) to use a different look up table and
why some can NOT be reprogrammed...their DB does NOT have that tire's
rev's per mile listed...




Drum/shoe braking systems do NOT have the ability to set and release
the shoes from the drums that quickly, as it has to travel much farther
than a disc/pad system (actually, the pad just kisses the rotor at
all times)

So the pulsation frequency for drum/shoe setups are much lower in frequency
Since most drum/shoe braking systems has one shoe self wedging, ABS
does not work well, as since they are self wedging...they will NOT
release quick enough for true ABS to work well

Maybe with a magnetic based shoe, it can be pulsated to simulate a
rudimentary ABS of sorts...but then the impedance of the magnets
would then become a factor on how fast they can be pulsated. The raising
and falling flux field would have too much inertia (impedance) to be
an effective ABS braking system

Then add in the known for most trailer OEM's NOT using the best practices
for their brake wiring, there are those impedance's from too small
a wire gauge, poor connectors and poor routing




If the tire continues to skid or approach skidding, the ABS computer will
continue to increase the pulse cycles to reduce the amount of braking
Why I don't really like ABS for 'me', as I can modulate my brake system
better than any of the ABS system on my vehicles



The PWM (Pulse With Modulation) of the IBC signal to the trailer is
just a form of controlling the signal. Instead of a steady voltage
signal. Simplistic explanation, but won't go into that technology here

Think that is the confusion thinking IBC's will ABS the trailer brakes

True ABS system for the trailer will require a tone ring (that ABS
sensor) on each trailer brake wheel/tire. There should be mention of
a 5th ABS channel (along with a disable or feature where it senses
whether there is a ABS equipped trailer)

Otherwise, it just buzz's (PWM) the signal. Think the frequency is set and
the amplitude (voltage) is variable, but am not sure and maybe they
do have the ability to change the PWM frequency

[marininn]

BenK, i think they are talking about voltage, not ABS.
From what I surmise, the on and off pattern of the brake controller is not for ABS, I was not thinking that, but for voltage. Sounds like the brake controller puts out the full 12 volts, but when it cycles on and off quickly it roughly equates to a lower voltage. Am I correct here?
So, 50% on 50% off time-wise yields a kind of dirty 6 volts (is what I assume). This happens too fast for the mechanical brakes to respond to, so the effect happens at the brake (the spring, pad and magnet).
If I understand… The brakes are powered by the movement of the wheel. The brake drum rotates around the stationary brake pad. The magnet pushes the pad into the drum and friction pulls the pad, or wedges it almost, into the braking action. Compared to the electronics on the other end, this is a slow process.
Someone add to this as is all I understand so far…

[BenK]

Controllers normally manage volts and amps comes along via Ohms law...there are
some current controllers, but they are more expensive (both parts and design)

As for using the TV's ABS to ABS the trailer brakes...as long as there is inertia
on the trailer braking system...they CAN NOT be ABS'd well...

Modulation of the friction on cast iron needs to be crisp (fast and short times
between voltage spike). DrumShoe setups CAN NOT be modulated fast enough for any
kind of effective ABS. Trailers with disc setups has the inertia of the on-board
trailer controller between the feed from the TV and the trailer disc brakes

[mkirsch]

The brake controller controls VOLTS. It's the only thing it can control.

The Volts it puts out in conjunction with the condition of the wiring and the condition of the brake magnets, is what determines how many Amps are flowing.

[Diesel_Camper]

Could be worn axle seals letting grease into one or more brake drums.

[Searching_Ut]

lenr wrote:
Whether the controller is controlling amps or volts is an interesting question. I always assumed it was volts. Amps is actually what determines the strength of the magnetic field but it should be directly proportional to amps.

I haven't ever checked a Ford, but my GM, Ram, and Prodigy controllers I've owned have actually controlled both voltage and current in a crude sort of way. What they actually do is send the full voltage from the Circuit breaker to the brake solenoids, but do so by switching on and off really rapidly. (Pulse Width Modulation) the frequency, or number of pulses per second stays the same, but the duration of how much of how much time during each pulse power is switched on varies (Duty cycle). Some millimeters, and all oscilloscopes that I know of can measure this for you, and with a scope you can see a graphical representation of the voltage waveform which is handy for visualizing what's going on. (Yes, I'm one of those guys who carries a pocket scope in the tool box of my truck)

If you have a newer RAM truck, the duty cycle maxes out at 65 to 66 percent, with Chrysler saying it goes up with speed. (My own testing says otherwise) My trailer brakes draw about 12.3 amps when connected straight to a battery, but max out at approximately 6.5 to 6.8 with the IBC on my truck. I'm still working with Chrysler to try to resolve this, but it causes inadequate braking to put it mildly. To add insult to injury my trailer brakes work fantastic if towed by my neighbors ford, or with a cheap aftermarket brake controller. How embarrassing ;-}

[lenr]

Whether the controller is controlling amps or volts is an interesting question. I always assumed it was volts. Amps is actually what determines the strength of the magnetic field but it should be directly proportional to amps.

[lenr]

I have experienced 3 different trailers that developed weak brakes because the electrical connections breaking. The connections outside the wheel are in a very bad envirement. I've gone from inadequate brakes at 10 to too much at 6 by doing a complete rewire with 2 12 gauge cables from the front of the trailer. 10 to 11 amps is kind of in between 3 magnets and 4 magnets--you might have 1 magnet with a broken connection.

[lenr]

Pretty sure that the manual for my F350 says that it only reduces output when activated by the brake pedal--the manual lever does not reduce.