Power voltage to brakes??

[ivbinconned]

Never been happy with braking on our C Creek. Just installing all new brake assemblies and checked voltage at right rear and it shows only 9.5 volts!!
This is not via the truck. I have it connected directly to a tested 12.6 volt battery .
Should I see that kind of a drop from the battery?

[Mmaxed]

Believe it or not, your IBC is much better over any of the current aftermarket controllers even with some of the short comings of it.

Absolutely not true, if his Ram is like my '15 was from the factory.

Someone at Ram decided that below 30 mph the trailer brakes would only need about 60% input. On the bigger brakes, 12" x 3" if memory served it was dangerous. More than one fellow reported rolling through an intersection. Ram did update the programming. My 2020 has very good trailer braking.

[Gdetrailer]

ivbinconned wrote:
Thanks. I had hoped that by soldering all connections at both ends of both axels I would get better results but if any it was only slight.
I did hook up to my much lighter goose neck flat deck and by pulling the brake lever the tires stand.
So. Would you recommend an aftermarket controller because of the weight of the trailer.
Where good response trailer brakes becomes very necessary is when descending a long grade in icy and snowy conditions.

Believe it or not, your IBC is much better over any of the current aftermarket controllers even with some of the short comings of it.

Comparing your gooseneck which is lighter and most likely shorter than your RV tells me controller you have is fine. If you had same problem with gooseneck that you have with the RV then the problem would be more likely on the truck end.

The only aftermarket controller I liked was the Jordan Ultimate 2020 which used a physical cable attached to your brake pedal.. That direct physical connection didn't rely on brake lights, brake light switches or complex computation curves required by accelerometer type aftermarket controllers. By the way, the accelerometer based controllers just like your IBC also trim down the output while sitting still. Stands to reason, if you are sitting still no need to keep applying the max output.

Unfortunately The Jordan Ultima 2020 was sold to Camco, Camco promptly dropped the entire brake controller business and the only option is to find used units and most folks that have one would rather take them to their grave over parting with them.

You had stated that you were getting 9V-10V at the axles when you pulled the break away pin, that is a huge drop from 12.5V at the trailer battery! A 3.5V drop is unacceptable, I would have expected not much more than .5V! You have either too light of wire from tongue to axle or you have damaged wire from tongue to axles. This voltage drop is excessive and using the trailer battery via the break away switch removes your truck as the main source of the problem.

Go back and reread my post which gives the wire gauge resistance and you can see for yourself how much percentage of braking power you can lose..

You really need to try to bypass the wire going from front to the axles, even if it is temporary to see if you have hidden damaged wiring. While wire now days isn't cheap, you could buy some 10 gauge SJ jacketed cable with three 10 gauge wires. Use that for a test, if you see an improvement as in less voltage drop then you may wish to consider bypassing the OEM wire permanently.

You could even use that SJ jacketed cable to make the bypass permanent or buy RV 30A 120V ends and make it an extension cord for your RV shore cord from the wire you bought for the test.

You can also use a 30A RV extension cord as a temporary bypass by buying 30A replacement plugs and make adapters for each end that terminate with wire..

You can even buy a couple of 25-50ft rolls of stranded "building wire" from Home Depot or Lowes (one in black and one in white) and use that as a bypass and even still use it if you need to bypass the OEM wire permanently.

Lots of ways to approach the problem.

[opnspaces]

The IBC may not put out full voltage sitting still so I would take the truck and IBC out of the equation. Do not hook the truck up at all to the trailer.

The breakaway switch it nothing more than an on off switch. If you pull the pin the connection is made. This is a simple 2 minute test that should tell you if you are getting full braking.

Again truck disconnected from the trailer as in no umbilical connected.
Pull the emergency breakaway pin. With the pin pulled take a voltage reading at the battery. Then take a voltage reading at each wheel. The wheel voltage should be within a tenth of a volt or two of the battery.

Plug the breakaway pin back in to stop draining the battery.

[ivbinconned]

Thanks. I had hoped that by soldering all connections at both ends of both axels I would get better results but if any it was only slight.
I did hook up to my much lighter goose neck flat deck and by pulling the brake lever the tires stand.
So. Would you recommend an aftermarket controller because of the weight of the trailer.
Where good response trailer brakes becomes very necessary is when descending a long grade in icy and snowy conditions.

[Gdetrailer]

Yes, most IBCs now days have some compensation for light or heavy trailers, your trailer weight most definitely would fit in the heavy setting. That should be helpful as it will tailor the output more for your heavy load.

But, I suspect you are still leaving a lot of braking power sitting on the table unused and unavailable until you can get more than 9-10V at the axles with your breakaway pin pulled fixed..

IBCs like most any brake controller can't supply voltages higher than the charging voltage they get from the engine. In fact most modern brake controllers use PWM or Pulse Width Modulation which switches the 12V on off rapidly. The width of the pulse is adjusted and the output average voltage varies with that width. They work like a buck regulator and does not have boost (can't increase output voltage above the input voltage. With a buck system, the max output is always less than the input..

So, it is critical to ensure all wire losses are minimized so all of your braking capacity is available.

[ivbinconned]

Ok
Here’s what I now know and can report. I have learned that my Ram will not provide full brake voltage standing still. It’s smart.
There is also a setting on the Ram to adjust that voltage response on the touch screen. Two options “ “light towing” or “heavy”. My has always been on light.
Learned this on a Cummins forum.

[C_Schomer]

FWIW, I had a cargo trailer that had much bigger magnets than the same 12 x 2 Dexter drum magnets that were on my fifth wheels and that cargo trailer stopped like a champ but the 5ers were terrible. The cargo trailer brakes had the biggest magnets that Dexter listed… I think they had white wires.
I wish I would have known the difference in the magnet sizes before I spent $1700 for disc brakes on my current fifth wheel.
I even tried premium riveted and pre-arced shoes on that lighter 5er with 10 gauge wire to both sides and there was minimal improvement from all of that work. The cargo trailer with the bigger magnets didn’t even need increased wire gauge to make it break so well. Craig

[Gdetrailer]

ivbinconned wrote:
The trailer is a 34 footer and around 12,500 pound.
Couldn’t get at it today but tomorrow I will start by testing my battery voltage under the load of full braking.
If it is good I will then cut the wires where they first appear under the belly at the first axel and test the voltage there.

The brakes two wires are encased inside there own grey coating and appear to be in a loom right to where they emerge under the belly.
We will report tomorrow.
Thanks for all your comments

Most likely standard off the shelf jacketed brake wiring, looks like this..



The problem is, with the wiring run with a wire harness or loom and disappearing somewhere and the resurfacing elsewhere you are not able to verify if there is multiple splices or damage to the wire.. With it hidden, you could have even had a rodent decide to make a meal out of the jacket and chewed through a bunch of the strands for good measure.

Then there is the added issue of typical RV manufacturing laziness of using a very small ga wire running through the axle tubes, that wire often breaks or gets chaffed.. Either way result is less than stellar braking.

[Gdetrailer]

ivbinconned wrote:
Ok. Just Cut the power wires to the first axle there I had 12 1/2 V. As soon as I hook up the brakes to the front axle only it dropped to 10 1/2 when I hook up the rear axle to the furthest away wheel I’m still at 9 V.

I’ll do a road test next and see if all new brake assembly’s has improved my breaking. So glad I have an engine brake on the ram.

There is still some seriously high resistance in the wiring, I would have expected no more than .5V drop and even that would be high.

If you have some 14 or 12 gauge wire hanging around, might be easier and faster to bypass the wire from tongue to the axle as a temporary test. You could feed the test wire through a window at the front and then out a window nearest to the front axle. Doesn't have to be super fancy for a test. Heck even a 14ga or 12ga extension cord could be employed and if you didn't want to cut the connectors of the extension cord you can make some adapters to connect it temporally.

Sometimes it is not worth the damaged brain cells to fret over the junk wire used by RV manufacturers and abandon it.

[Gdetrailer]

Glad folks have found some of my information helpful so far!

For a bit more advanced information I have done some "back of the napkin" noodling.. Bear with me, this got a bit long..

Wire line resistance has a profound effect on low voltage and low resistance items so to demonstrate how much this can affect your electric brakes braking efficiency I have made some measurements to get some known information of what voltage is needed to get a brake magnet for 3,500 lb axle family to draw 3A.. From the voltage an current measurements I can calculate the DC resistance of the brake magnet.

To get 3A draw from a brake magnet I set my adjustable lab power supply to 12.21V at the brake magnet wire connections, measuring only one magnet (my adjustable Lab supply only can handle 6A per output).

Brake magnet measurement of 3A at 12.21V = 4.06 Ohms

4 magnets at 4.06 Ohm in parallel = 1.015 Ohms (resistance in parallel is divided by the quantity)

Assuming 25’ from tongue to brakes, we must double the length since we must account for pos and negative wires = 50’ of wire.

So for our calculations we are assuming 50ft of wire round trip.

For different lengths of wire or different ga of wire refer to a wire resistance calculator, I used
THIS ONE HERE

16 ga = .201 Ohms add that to 1.015 Ohms = 1.216 Ohms.
Divide 12.21V by 1.216 Ohms = 10.04A
Divide 10.04A by 12A = .87 or 87% of max braking, basically 13% loss of potential braking.

14 ga = .126 Ohms add that to 1.015 Ohms = 1.141 Ohms
Divide 12.21V by 1.141 Ohms = 10.7A
Divide 10.7A by 12A = .89 or 89% of max braking, basically 11% loss of potential braking

12 ga =.079 Ohms add that to 1.015 Ohms = 1.094 Ohms
Divide 12.21V by 1.094 Ohms = 11.16A
Divide 11.16A by 12A = .93 or 93% of max braking effort, basically 7% loss of potential braking

10 ga = .05 Ohms add that to 1.015 Ohms = 1.065 Ohms
Divide 12.21V by 1.065 Ohms = 11.46A
Divide 11.46A by 12A = .96 or 96% of max braking effort, basically 4% loss of braking potential

8 ga = .031 Ohms add that to 1.015 Ohms = 1.046 Ohms
Divide 12.21V by 1.046 Ohms = 11.7A
Divide 11.7A by 12A = .98 or 98% of max braking effort, basically 2% loss of braking potential

6 ga = .02 Ohms add that to 1.015 Ohms = 1.035 Ohms
Divide 12.21V by 1.035 Ohms = 11.8A
Divide 11.8A by 12A = .983 or 98.3% of max braking effort, basically 1.7% loss of braking potential

To be clear, every single splice or wire connection will add some resistance, absolutely no splice is 100% resistance free and that resistance adds to the overall wire resistance. Moisture from the air and even direct moisture getting into unprotected splices over time creates a oxide coating on the wires in the unprotected splice, that coating affects the resistance of the splice and with repeated exposures over time weakens the wire to the breaking point adding further resistance. Damaged or compromised insulation can allow moisture to seep into the wire and degrade the wire.

It is critical to use a good moisture proof connectors if the connector is going to be exposed to the weather (yes, even the connections under the trailer get exposed to moisture, driving in rain splashes water and soaks the underside of the trailer).

For the ones advocating using Amp meters to trouble shoot this, generally most DVMs with built in 5A or 10A amp reading will insert too much resistance and that resistance will severely affect your overall circuit amperage draw and reduce the voltage, severely skewing your measurements and results.

[ivbinconned]

Ok. Just Cut the power wires to the first axle there I had 12 1/2 V. As soon as I hook up the brakes to the front axle only it dropped to 10 1/2 when I hook up the rear axle to the furthest away wheel I’m still at 9 V.

I’ll do a road test next and see if all new brake assembly’s has improved my breaking. So glad I have an engine brake on the ram.

[MFL]

^ eHoefler...good explanation! Some excellent points here, from a man that understands the trailer braking system!

Jerry

[eHoefler]

As long as all 4 brake assemblies are connected, you will never see 12 volts at the magnets, each of them are a designed short to ground and, will drop the voltage. Every splice in the system adds resistance and will drop voltage. If the splice is not a solid connection and water tight, they will corrode, add resistance, and drop the voltage. The cross over wire are usually inside the axle tube, where the jump around, rub, and chafe, which will short to ground and drop voltage.

I can go on, but I digress.

To improve performance, each magnet should have equal wire length to the source. The way they wire them, using under sized wire, is to run one lead down one side or the other, splice at the first axle, then to the second axle, then splice each axle to the other side. Resulting in the farthest wheel from the source will be the weakest braking wheel while the first in line closest to the source being the strongest.

The best way to wire them for best performance is to run 2 wires, one down each frame rail, then splice them at the center of suspension to each wheel. That way you will have the same wire length to each wheel.

And while your at it, use 10ga wire down the frame rails and splice 12ga to each wheel.

When all done and said, and got tired of not having comfortable feeling braking, I replaced the whole system with disc brakes and have never looked back.

[GottaRunGottaCa]

Gdetrailer, thanks for the great information, time to start checking things till I find the problem, What I meant about locking up the brakes is just for setting up the gain on them, and yes you don't want your trailer brakes to lock up.
Again thanks for the information!

[ivbinconned]

The trailer is a 34 footer and around 12,500 pound.
Couldn’t get at it today but tomorrow I will start by testing my battery voltage under the load of full braking.
If it is good I will then cut the wires where they first appear under the belly at the first axel and test the voltage there.

The brakes two wires are encased inside there own grey coating and appear to be in a loom right to where they emerge under the belly.
We will report tomorrow.
Thanks for all your comments