Improving brakes performance

[femuse]

It has been suggested that an improvement in braking power can be had by increasing the size of the wire throughout the system from the typical 14 or 12 gauge up to 8 gauge. That would be from the battery, to the controller, and all the way back to the magnets at the wheels. Additionally, the same wire size could be used for the brake magnets Grounds, running them all the way back to the tow vehicles battery negative terminal.

No doubt the reduced resistance would result in more of the voltage reaching the magnets. But would this really help? Judging by the wire size provided by the controller manufacturer, it doesn't appear that they think the brakes require a huge current to work efficiently.

What do you think ?

[Pick]

Mike, what I think, is that the brake controller has a lot to do with how good your brakes work. Since replacing my Voyager with a Jordan, I have seen quite a difference in brake performance. As far as I am concerned that Voyager shouldn't even be on the market, in my opinion. The difference is astounding.

Now one of the nicest things about a Jordan is the buit in AMMETER. You should in theory, be drawing 3 amps per brake magnet, so a 4 brake system will draw 12+ amps at full braking power. With the built in digital ammeter you KNOW if all magnets are working. If you are drawing 12 amps and not stopping then you know the brakes need adjustment or some other kind of maintenance. This also tells you your wiring integrity is good.

All the Voyager has is a red led. You know how much current is being drawn by how red the led turns, but since it works on 1-4 axle brake systems, it really doesn't tell you anything, except that it is sending SOME current to the brakes.

[Silvertwinkie]

I think based on my findings on the forum that controller has a bunch to do with it (as long as the brakes are in good shape and good working condition).

I found that the Voyager isn't really really that good. The brakes seem to be grabby, need constant adjustment, etc which is similar to what others were posting about it.

I found a member on the forum that had a used Prodigy that he wanted to sell. I bought it because it got rave reviews from folks here and in a few other circles. So I am going to try that. If that does not improve it, I will try the Jordan next since I think I recall that was the next one on the list.

I'll post when I get the unit and have some time on the unit to compare the findings on both Voyager to Prodigy.

I miss the old brake units that were tied to the cars master brake cyl. Those units worked flawlessly. These electronic ones are nice, but so far my exp with the Voyager has been less than positive.

Regards,

Eric

[femuse]

OK, guys, nice try.... but ....that was not our question:

It has been suggested that an improvement in braking power can be had by increasing the size of the wire throughout the system

Bellow is an answer on target, we received from "Lou Schneider on the Escapees Forum:"
Could somebody comment on this please ?

"Let's take a typical example, upgrading from #14 wire to #8.

"14 gauge wire has a resistance of .0026 ohms per foot.

"Trailer brakes draw 3 amps each at their full rating, so four brakes will draw 12 amps.

"12 amps * .0026 ohms = 0.031 volts lost per foot of #14 wire.

"A typical 30 ft. 5th wheel will have at least 30 ft. of wire between the controller and the trailer brakes. Multiply this length by two, since the current has to go to the trailer axles and back again.

"60 ft. * 0.031 volts per ft = 1.86 volts lost along a run of #14 wire.

"Now let's look at using #8 wire.

"8 gauge wire has a resistance of 0.00067 ohms per foot. At 12 amps it will lose 0.008 volts per foot, about 1/4 of the voltage lost in #14 wire.

"60 ft. * 0.008 = 0.48 volts lost along a run of #8 wire.

"The difference is 1.38 volts, or about 11% of the system voltage.

"Gaining 11% in voltage delivered to the brakes may not sound like much, but remember that Power = Voltage squared. 11% more voltage = 22% more power developed by the brake magnets.

"Your mileage may vary, depending on the particulars of your rig. But the numbers are nothing to sneeze at."

Any thoughts on his comments ?

[Silvertwinkie]

If it's a mod your interested in, that's great, but I would assume that unlike GM they engineer it thinking of voltage loss. I gotta tell you, that the voyager brake controller, even with the voltage loss still can lock the brakes on the trailer loaded, no problem. Could that be because there is more meat to grab since it's very new? Perhaps, but properly maintained brakes I don't think would make a difference if you lost 1.38 volts. Power may equal voltage squared, but remember all you are doing is forcing brake pads/shoes against a drum/disc. Now add the fact that you would have 4 well maintained brakes, that should be able to stop your rig with the assistance of the two vehicle.

If if gives you piece of mind, fantastic, but also keep in mind that I am dealing with only one axle and 5000lbs gross.

I could also compare this situation to the way GM does front disc rear drum brake proportioning. On a 5300lb gross car, the front has 65-70% of the braking. The rear drums get about 30-35%. Given those stats, could the car stop better,? Sure, if I had the time, money and desire. But it's within spec and still can stop on a dime provided I have all 4 brakes in proper condition.

Anyway, those are my .02 comments.

I'm sure John HD could comment further.

Eric

[femuse]

Eric, Thank you for your comments.

Having been through a few brake controllers, I have some idea what they Can and Can't contribute to trailer brake performance.

However, my post was about the effect of a change in wire size and the attendant decrease in electrical resistance. I never mentioned whether I was or wasn't delighted with the performance of my current brake setup.

Over the past 12 years I've dragged travel trailers through most of the states east of the Mississippi. Much of it on the smaller mountain roads. I've experienced more than simply inadequate brakes. We've seen plenty of brake fade from heat, brake lock-ups, hydraulic failures, disk failures, and brake fires, and I've been on a couple of unwanted roller coaster rides. I take braking seriously.

Discounting under-loading, I don't think I've ever seen a rig that had too much braking power. And probably as important is precise control of the braking action. Brakes that lock up can kill you quite as dead as those that don't. If someone plausibly suggests I might make a refinement to my braking system that might help realize its full potential, I'm going to look in to it.

The gain in power at the magnets sounds interesting to me and I intend to pursue it further.

Thanks again for your interest.

[j54mark]

If the brakes can be locked up with the existing wiring, it is not at all clear to me what bringing higher voltage to the brake magnets is supposed to accomplish. If, on the other hand, the voltage was not high enough to allow the maximum braking possible, I could see making the change.

Could higher voltage allow better control? That is, could it allow the brake controller to act with more finesse?

Mark

[Pick]

Mike, I guess the real solution to the question is this: Hook up a digital voltmeter to the brake magnets at the splice and see, if indeed there is a need for increased wire size. It would be also helpful to know how many WATTS the trailer magnets are capable of handling. An increase in voltage could be detrimental to the magnet coils, and cause heating, shortening the life of the magnet. I doubt however that this is the case. I would think that they would engineer them to withstand 18-24 volts.

They say the new oval magnets have 40% more power than the earlier round magnets.

[john hd]

to quote pick:" They say the new oval magnets have 40% more power than the earlier round magnets."

i would make sure everything was in working order first, then upgrade the magnets if you had the round ones. before rewiring the truck and trailer.

mike,

can you even tell if the trailer is brakeing behind that international?

the brakes on mine at work are very good. (air) even with huge loads behind it i have not noticed any lack of stopping power.

john

[Silvertwinkie]

John,

I'd be interested on your thoughts on femuse's post at 10:43am today. I know you are the pro when it comes to electricity. Whadda think of the different wires vs. delivered volts, etc.?

Eric

[femuse]

1-No airbrakes.
2-When we have to change the magnets, will make sure we get the oval ones.
3-What a lot of people have missed: this was a rethorical question. Mike had followed various conversations on that subject on Compuserve. So he was curious. Could always be useful in the future.
We do not have any problem with our brakes. In fact we have used our new trailer only 160m to take it home with the van. Flat ground.

can you even tell if the trailer is braking behind that International?

Only because we tested it carefully and know what it feel like. Do we need brakes? By law : YES. I guess we want them anyway.

Here is a question for you John:

I hate the common crimp connectors you find in blister wrap at parts stores. The finished job looks half baked and failure prone. More to the point, I'd expect them to have high resisitance due to the nature of the contact between the wire and the sheath it is inserted into.

On the Compuserve CARS Forum, I got into an interesting discussion when I suggested that soldering connections would have to be better that crimp connectors. Some of the respondents had aircraft experience and made a strong case in favor of well made crimp connections, but also made the point that industrial crimp tools made a much superior job of it. That leaves me still wondering about the type of crimp joint I'm likely to produce without specialist tools, etc.

It was also argued that soldered joints had a tendency to be fragile. The idea being that for a number of reasons, wires often fracture immediately next to the solder. I found that interesting and credible, but I don't think it is necessarily unavoidable.

What do you think?

[femuse]

Pick

I do plan to use a multimeter. And in fact, this might be just the excuse I need to get an Ameter. We'll see.

I kind of think the magnets are going to be designed for the maximum an automotive system is likely to put out. There's probably a margin of top of that. But I really don't know, but I really doubt that running heavier wire will do any harm.

I had heard that the oval magnets were more powerful. Also that they don't wear as fast. I'd be happy with either one of those benefits.



Mark

If the brakes can be locked up with the existing wiring, it is not at all clear to me what bringing higher voltage to the brake magnets is supposed to accomplish

Frankly, I'm not at all sure I understand that either. One benefit might be that given fully realized peak power, you might be able to spread the spectrum of power levels over a broader range instead of being force to set your controller to the max and hope for the best.
I like your use of the term "finesse". Braking should involve real control.

Thanks

[john hd]

mike

i was taught at line school that good connections are:

clean

tight

adequate (right size)

i have used soldered connections in high vibration areas on my vintage bike for years. with no failures. but, i always use heat shrink tubing over a splice. it acts not only as an insulator but also provides strain relief. it also keeps the water out.

not running a ton of solder into a joint helps too, don't fill the wire up! just the joint. pre tinning helps this so less solder is used.

i also use crimp connectors with a good quality tool, makes good joints. i also use shrink tubing on these for the same reasons.

on connectors that terminate at a screw i slide the wire through the connector just enough to be captured by a washer. a little extra insurance if you make a bad crimp.

loom your wires! not letting wires blow around or vibrate will last longer!

you get what you pay for with connectors! buy good stuff and you will get good results. tools too!

as far as your idea about the wire size, i see no flaw in your logic. if you find that you have excessive voltage drop, more than a couple of percent, then change the wire size.

assuming all of your connections are in good working order of course.

with the overall length of your rig, i can understand why this might be an issue for you.

john

[nickcrowhurst]

I find it useful to be able to disconnect the wires behind each wheel and measure the current to individual wheels when the brake line is activated. I use a digital voltmeter with a 20 amp capacity.This helps me to track down an imbalance in braking, indicated by differing hub temperatures between wheels after a trip.In automobile or marine work I use solder and heat shrink for a beautiful result, but for Airstream brake lines I use exterior grade wire nuts, pre-filled with silicon, (Home Depot), or fill my own empty wire nuts with silicon calk. Just another option, but it works for me. Nick.

[Inland RV Center, In]

Round brake magnets cannot be replaced with the oval magnets.

If someone wants to update their brakes to the more efficient "oval" magnet type, then the entire backing plate must be changed.

The round magnet 12 inch brakes have 5200 pounds maximum braking power, per axle. The 12 inch oval brakes have 7000 pounds per axle.

Andy
inlandrv.com
airstreamparts.com
airstreamcandy.com

[femuse]

Andy

As far as we know, our brakes are OK for now (used trailer only 160 miles, haven't looked at brakes yet).

We have a question for the future:

Do you know what magnets they would have used originally on an Excella 32' 1990 ?

When did they start using oval magnets, and are the round magnets discontinuted ?

Thanks

[Inland RV Center, In]

Round magnets are still available.

Oval magnet brakes have been used since the mid 80's.


Andy
inlandrv.com
airstreamparts.com
airstreamcandy.com

[femuse]

Andy : thanks


Nick,

I find it useful to be able to disconnect the wires behind each wheel and measure the current to individual wheels when the brake line is activated.

Are you arguing against making a solder joint to each magnet? Or is this process a one time only affair?

I use a digital voltmeter with a 20 amp capacity.

It looks as though I'm about to buy one myself. There are several ways I'll need it in the near future.

...imbalance in braking, indicated by differing hub temperatures between wheels after a trip.

Yes. I always check the temperatures at the hubs, drums, and tires after the first few miles. After that I check at fuel stops or any other opportunity.

...but for Airstream brake lines I use exterior grade wire nuts ...

Is this because, knowing you'll be replacing magnets occasionally, you don't want a permanent connection?

...exterior grade wire nuts ..., pre-filled with silicon ...or fill my own empty wire nuts with silicon calk.

Sounds like a good way to keep the water out. Good idea.

Many thanks


John, Thanks for several good points:

use heat shrink tubing over a splice. it acts not only as an insulator but also provides strain relief. It also keeps the water out.

not running a ton of solder into a joint helps too, don't fill the wire up! just the joint.
pre thinning helps this so less solder is used.

use crimp connectors with a good quality tool

connectors that terminate at a screw ... slide the wire through the connector just enough to be captured by a washer.

loom your wires!

you get what you pay for with connectors! ....... buy good stuff

voltage drop, more than a couple of percent, then change the wire size.

Regarding soldering: "don't fill the wire up! just the joint"
I take it you mean not to let the solder creep up the wire, away from the joint?

As far as good tools and connectors: I tend to buy at NAPA, but as I mentioned, I'm not delighted. Is there a better place to buy? Tool-wise, I bought the best crimp I could find, but I'd say it's only marginally better than the stamped steel one I already had. Where do I find a good one and what do I look for ?

Somebody on the Escapees Forum told us:

" If you are bothered by the common crimp connectors (especially under your trailer) you could use the GM weatherpack connectors. These are available from any good parts store. Hot rodders use them when rewiring a car. They are wetherproof and you can get them with 2 or even 10 or more contacts. Soldering is still required. "

We have not been able to find them. Any idea ?

Many thanks

[john hd]

"I take it you mean not to let the solder creep up the wire, away from the joint? "

yes that's right!

as for tools, i believe the good ones are made by an outfit called AMP.

i'll look around and see...

john

[john hd]

mike

i'm sure your napa tool is ok, this is what i am reffering to...

crimper

this kinda stuff is way out of my budget!

if you ever find one, let me know if i can borrow it!

john