Thoughts on running 12v Trailer Brakes on 24v

[wanderingwillys]

I have a 66 M35a2c and tow a 79' zehman flat deck trailer with 12v electric wheel brakes - I am wondering if what thoughts you all have about using 24v to trigger the electromagnatic brakes - should work just as a 12v system does (magnet shouldn't care 24v vs 12v...)

I was thinking about 3 seperate ways...

1. A rheostat on the dash to control the inlet voltage to the brakes and then a push button moment switch for those times where you want to dump the trailer brakes...

2. Using the 24v signal from the stop light switch to actuate a 24v relay which would switch a 12v source drawn from the bottom battery in the stack. Again with the same type of modulation at the dash...

3. Pull a 12v feed and use an inertia based brake controller to run the trailer brakes independant of the truck brakes...

I want to be able to use the trailer with a 12v truck and the 24v truck so mods to the trailer are a last resort.

I am putting in LED lamps and will either get units the can handle the range or 12v to 24v or make a jumper off the duece harness that integrates resistors...

I welcome any thoughts on the electromagents in the trailer brakes...

Matt

 

[Pinz25086]

Not sure but I think that the brakes would be applied twice as hard with 24 volts going to them. I would stick with a way to keep the voltage below 14 at the brake magnet. What about wiring the 2 brakes in series as each would use half of the voltage?

Wayne

 

[Sephirothq]

I have a write up on how to do this with a voltage converter. search for my user name you should find it.

 

[wanderingwillys]

I am also looking at going to hydraulic brakes and then use the air pack and m/c off a M200 trailer so I just use the gladhands on the rear of the truck for brakes...

Maybe convert one axle and leave one - then it'll have both electric and hydraulic...

 

[Wolf.Dose]

If you run 24 V through your selenoids of the electric brakes, they will become hot very fast and the braking force will increase (the magnetic force inreases due to higher voltage). And shortly in braking, the brakes will fail due to overheating of the selenoids. The propper testing for that is: full voltage and current for at least 15 minutes. If the brakes survive that without damage, you might use them. If not, ok, they need replasement anyway.
The idea of the use of a voltage reducer is not a good one, for the electric brakes use quite some current. So the reducer will be very expensive to survive this necessary load.
You have air on your truck.
So I would use air brakes on the trailer. If necessary, change axles to air braked axles or use the system with the air actuating a master cylinder with hydraulic wheel brakes. Someone should help you to calculate the correct dimensions of the hydraulic brakes, if you can not do that by yourself. Try and error is to dangerous on brakes.
Wolf

 

[m16ty]

There's a place in Australia that makes an electric brake controler that takes 24v in and outputs 12v to the brakes. I posted the link some time back. I'll see if I can dig it up.

 

[m16ty]

Here's the thread. http://www.steelsoldiers.com/deuce-...g/56185-air-over-electric-trailer-brakes.html

There's also a link in the thread that shows a air over electric setup but you still have to deal with the 24v output with it. I think the 24v/12v controler is the way to go. I contacted the company and while they don't have any dealers in the US, they said they would ship me one.

 

[shovelheadmike]

I would wire up the trailer breaks so they could be switched to work in series for 24 volt and paralled for 12 volt. Use the newer LED brake/tail lights that will work on either voltage.

It would really be a bad thing to burn up the breaks with 24 VDC and then need them to work for a panic stop. BANG, Crunch!!! So much for big trucks hauling a heavy trailer and little cars... Had a personal experience with that once. Very ugly. Car hit totaled, while on the truck I just bent the brush guard. Not a scratch on my truck, terminal for the car (actually a minivan). Wreck happened on Ft. Bragg on Gruber St., so got to go to federal court.

 

[Stalwart]

Or get a battery equalizer that gives plenty of 12V from a 24V system. That's what I'll be using on the HEMTT for all my 12V systems. They run about 97% efficient and only take 3 connections. You can either use the output to power your 12v loads directly OR you can tap the ground side battery for the load and the equalizer will balance the batteries. You can find them on eBay new and used. I got a 100A model new for about $100 plus shipping.

 

[wanderingwillys]

I am leaning towards the air over hydraulic option and will be putting the Maxxima 12-24v LEDs every where so that will be a non issue....

As for the brakes it is easy enough to do the math to correctly size the M/C to the W/C's

Might just use an civy brake controller and some form of isolator or equalizer...

We'll see how it goes... I used to build trailers so I know the brake systems very well - just never had to deal with a dual voltage system....

Matt