Electric brakes, how it works

[Hugo-H]

I have a Bullet Premier Lite 31BHPR (2016).
Today's vehicle inspection showed me that the brakes don't work sufficiently enough...(although I adjusted them before going to the vehicle inspection(

Front axle 50%
Rear axle 33%...
Can anyone help me by telling me how the brake system on the trailer is build up?... a diagram would be very helpfull too...(since I cannot reach the keystone site from where I live in Europe...

I suppose the brakes don't use the voltage coming from the brake controller directly...

[flybouy]

50% 30% of what? Voltage? Yes, the brakes from the factory are powered by a single blue wire carrying varying positive voltages directly from the tow vehichle brake controller. The ground (or negative) is carried by a white wire. The 4 brake magnets are wired in parallel so each wheel should be receiving the same voltage.

[Hugo-H]

Originally Posted by flybouy

50% 30% of what? Voltage? Yes, the brakes from the factory are powered by a single blue wire carrying varying positive voltages directly from the tow vehichle brake controller. The ground (or negative) is carried by a white wire. The 4 brake magnets are wired in parallel so each wheel should be receiving the same voltage.

The 30 and 50% is the efficiency, compared to 100%...
Inspection requires at least 50% per axle, and both axles together should be also at least 50%...

[Hugo-H]

thx...so there is no kind of electronic device between the blue cable from the car's brake controller and the magnets on the axles?...

[chuckster57]

50% of what? How do they determine it?

If for example you have a Tekonsha prodigy brake controller, it will vary the output voltage based on settings and conditions.

[flybouy]

Originally Posted by Hugo-H

thx...so there is no kind of electronic device between the blue cable from the car's brake controller and the magnets on the axles?...

Not from the factory. How do they determine the the breaking efficiency?

[JRTJH]

There are multiple factors to consider in determining how the RV braking system functions.

First, you have to determine which brake controller you're using and how it functions. As said previously, a proportional brake controller will only apply a portion of the maximum braking electrical power, based on conditions it senses at the time.

Second, the "total braking power" is divided by the number of brake magnets connected to the system. As an example, if the "maximum available power" (100%) is controlled by the brake controller which determines that only 60% power is required for the specific braking action, then that 60% is divided by 4 on a tandem axle trailer, and 15% of the maximum is applied to each brake magnet for that event. There are, in my estimation, very few "100% power applications", except for when the break-away device pin is pulled. If so, then there would be far more "locked wheel stops" than there are "proportionally managed stops"....

Third, in many "newer brake controllers" there is a speed circuit. If the vehicle/trailer are not moving, the brake controller "KNOWS" that braking is not required and only a token signal or no signal at all is sent to the brake magnets......

So, depending on what type of brake controller and the conditions at the time of "braking demand" you may not ever reach the "required inspection criteria"...

Here's a few links to a RV brake theory for you:
https://vehq.com/electric-trailer-brakes/
https://www.curtmfg.com/trailer-brakes-controllers
https://www.hayesbc.com/how-to-trail...-systems-work/

[Hugo-H]

Originally Posted by JRTJH

There are multiple factors to consider in determining how the RV braking system functions.

First, you have to determine which brake controller you're using and how it functions. As said previously, a proportional brake controller will only apply a portion of the maximum braking electrical power, based on conditions it senses at the time.

Second, the "total braking power" is divided by the number of brake magnets connected to the system. As an example, if the "maximum available power" (100%) is controlled by the brake controller which determines that only 60% power is required for the specific braking action, then that 60% is divided by 4 on a tandem axle trailer, and 15% of the maximum is applied to each brake magnet for that event. There are, in my estimation, very few "100% power applications", except for when the break-away device pin is pulled. If so, then there would be far more "locked wheel stops" than there are "proportionally managed stops"....

Third, in many "newer brake controllers" there is a speed circuit. If the vehicle/trailer are not moving, the brake controller "KNOWS" that braking is not required and only a token signal or no signal at all is sent to the brake magnets......

So, depending on what type of brake controller and the conditions at the time of "braking demand" you may not ever reach the "required inspection criteria"...

Here's a few links to a RV brake theory for you:
https://vehq.com/electric-trailer-brakes/
https://www.curtmfg.com/trailer-brakes-controllers
https://www.hayesbc.com/how-to-trail...-systems-work/

how they determine it?... I think they measure the friction...and the computer gives the result output..
I have a controller Prodigy 2...working through an inertia sensor???, and it always has been working good... few days before I went to the inspection, I took off the drums to clean the brake shoes... and I saw that the shoes on the rear axle were worn out less then the shoes on the front axle (I included 2 pics from the right side front and rear)... I regulated them equally, but still not enough braking power... IF, the blue wire is connected to the 4 magnet wires in parallel, without any kind of box or device between them... I start thinking it can be an electric problem with the wires or grounds of the magnets... Problem is, I have no idea how to check it (which procedure) to determine where the problem can be?...

[JRTJH]

Have them "use the manual braking lever/slide on your Prodigy controller. That "might apply 100% power and pass the test".

I can't imagine that if the brakes were working prior to your maintenance and adjustment, that suddenly there would be a problem with corrosion or loose terminals that developed at a distant connection from where you were working.

So, if you adjusted the brakes properly and didn't contaminate the brake surfaces with grease during bearing packing, you should not have an issue with "corrosion or loose connections somewhere in the wiring" if you didn't touch the wiring.....

[Hugo-H]

I used the lever on the brake controller, because it's the only way the brakes can be tested...
However...during our last trip (last month) on our way back home, I noticed already a less efficiency when stopping on the road, after crossing several steep mountainroads... but I thought it would only be a matter of regulation of the brake shoes... I drove around 4000 miles... Since we have a quite high humidity over here (around 80% during autumn till early spring months ) and the TT was stationed from last November till July... could it be, the humidity interferred with the electric cables?... I can not follow the leads from the magnets, since they enter the under belly cover on the TT...

[chuckster57]

Moisture shouldn’t affect brake wiring as there should be waterproof connectors at the backing plates.

3-4 amps per magnet is the general rule so if you put a DC amp clamp on the wire coming out of the break away and pull the pin you should see 12-16 amps on a tandem axle trailer.

[Hugo-H]

Originally Posted by chuckster57

Moisture shouldn’t affect brake wiring as there should be waterproof connectors at the backing plates.

3-4 amps per magnet is the general rule so if you put a DC amp clamp on the wire coming out of the break away and pull the pin you should see 12-16 amps on a tandem axle trailer.

the 12-16 amps, under normal working condition while driving, is the max current delivered by the brake controller directly?

[chuckster57]

Originally Posted by Hugo-H

the 12-16 amps, under normal working condition while driving, is the max current delivered by the brake controller directly?

I haven’t measured actual amps sent by the brake controller during normal operation. We pull the break away to verify the brakes are all working. Too many amps means there is probably a short and too few means probably a broken wire.

[flybouy]

Originally Posted by Hugo-H

the 12-16 amps, under normal working condition while driving, is the max current delivered by the brake controller directly?

From the factory there is no device between the output of the break controller and the magnets. There are a few plugs/ wire connections but nothing else.

[Hugo-H]

Is there any point on the brakes that need to be lubrificated?... like the magnets are mounted on a pivat arm...perhaps that pivot point and what else?... anybody has experience with it?

[chuckster57]

Don’t use any grease on anything other than the bearings. There is no need to lubricate the magnets, shoes or any pivot points.

[wegone]

Goodness, this sounds very confusing.

My brake controller came stock on my truck which allows me to adjust gain, the amount of braking applied to the trailer.

I can squeeze it to 100% in an emergency, or adjust to where I can barely feel the difference when I roll on level ground, I leave it there.

However, I use my tow/haul mode to control my downhill speed where braking is used sparingly....

Am I missing something?

[chuckster57]

Originally Posted by Island Eddie

Goodness, this sounds very confusing.

My brake controller came stock on my truck which allows me to adjust gain, the amount of braking applied to the trailer.

I can squeeze it to 100% in an emergency, or adjust to where I can barely feel the difference when I roll on level ground, I leave it there.

However, I use my tow/haul mode to control my downhill speed where braking is used sparingly....

Am I missing something?

I don’t think so. It started off as a discussion about how to measure the “efficiency” of the brakes. OP is in another country trying to pass inspection.

[flybouy]

Originally Posted by Island Eddie

Goodness, this sounds very confusing.

My brake controller came stock on my truck which allows me to adjust gain, the amount of braking applied to the trailer.

I can squeeze it to 100% in an emergency, or adjust to where I can barely feel the difference when I roll on level ground, I leave it there.

However, I use my tow/haul mode to control my downhill speed where braking is used sparingly....

Am I missing something?

It would help if you had a signature as required by the forum community rules. The tow/ hual feature depends on the year/make of truck as to how it works. It does not replace or apply the brakes. Depending on the truck it may simply downshift the transmission or also restrict the exhaust to create back pressure and create resistance. In any case, it's an aid in braking, not a replacement for the brakes.

[wegone]

I have my TV listed in my profile under "about me"....
Does it go elsewhere?
I do need to update my trailer tho

Goodness, I never said tow/haul was instead of brakes, that makes no sense.

I see folks riding their brakes down long grades, and I always have to answer my wife's question: "Those aren't are brakes are they?"