24 v / 12v wiring

[schnitzel]

Okay not totally toyota related but does involve the trailer I use for towing.

At present i use a 12 volt vehicle for towing however for a number of reasons i am about to buy a motorhome which is 24 v to do the towing. Problem is trailer needs to be usable for both 12v and 24 v and I dont want to keep swapping globes.
Lights are easy to fix nowadays with the multi voltage LED lights now available and I will be using these so they are not a problem, trailer however has electric brakes and carries it's own 12v power.

Question is can i use a relay in the brake circuit which will let me trigger brakes on either 12v or 24 v by using the 12v battery on the trailer to feed the brakes. i.e. is there a relay available which will allow me to use both 24v and 12 v as switch.

Note have already worked out how to keep battery on trailer charged at all times.

[YLD-16L]

The relay like you mentioned or a voltage converter (google them there are heaps available) would do the job.

I was looking at voltage converters last week to go from 12V to 5V and noticed that there were lots available with a wide range of voltage conversions. Jaycar, DSE etc seemed to have a few.

[celicapain]

yeah, most low voltage relays are designed to run 5-30 v dc, so you shouldnt have a problem. just go to jaycar.

[RA40peter]

You can but you will need an electric brake controller that is mounted on the trailer. This way you can supply a relay with either 12v or 24v from the tow vehicle which will switch the 12v in the trailer to turn on the controller. The controller will then determine how much brake to apply. If you use a controller that mounts on the dash then convert that output to 12v, you will only ever apply full brakes to the trailer.

Peter

[schnitzel]

You can but you will need an electric brake controller that is mounted on the trailer. This way you can supply a relay with either 12v or 24v from the tow vehicle which will switch the 12v in the trailer to turn on the controller. The controller will then determine how much brake to apply. If you use a controller that mounts on the dash then convert that output to 12v, you will only ever apply full brakes to the trailer.

Peter

Thanks your input, this makes me think that perhaps I should be running the brake controller ( I Use a tekonsha Prodigy which is an awesome unit) after a 24 v to 12v transformer and isolating it from the bus power system, and switch it through a relay firing from earth. Will need to check now what amperage I can get from the transformer as require 30 amps to run the brakes.

Greg

[Kebin]

What you need is a 24v to 12v voltage reducer. The company Redarc make them... quality endorsed company etc. I fit the type of reducers your after at my work for similar aplications.
Heres a link: http://www.redarc.com.au/vrt.htm

[BradW]

I would suggest using a dash mounted trailer brake control unit such as the Tekonsha Voyager. We fit these at work and have never had a problem. They are easy to fit, easy to operate, reliable, have adjustable gain control so you can adjust how much force is applied by the trailer brakes and a slide control to apply the trailer brakes independently of the motor home brakes (very good for controlling a trailer that is starting to sway around behind you ).

For a 24v vehicle you will also need to use one of these. These are a very handy item that will integrate the 12v brake light input required with the brake controller, with the vehicles 24v brake light circuit. It also has a built in charge equalizer that allows you to run the brake controller off the 12v side of your vehicles battery bank. Have a read of the page, it will explain how it works.

This setup will give you full control of the trailer brakes from the drivers seat of the motor home without having to modify the trailer at all. It isn't the cheapest option but I believe it is the safest.

[Kebin]

Also shop around amongst the other brands because Redarc isnt that price friendly

[schnitzel]

Had a look at the redarc site, they make a vrt 30 which will do the job, but as you said they are pricey so will check out Jaycar etc.
Scary thing nowadays is I must go into jaycar too often thay all know me by name, helps that one of them is a celica nut though.

[Kebin]

helps that one of them is a celica nut though.

So doesnt that mean special celica nut discount then??