For the auto elec gurus out there. Would it be possible in theory to power the brake controller (and hence your van brakes) from your on-board van battery?
Brake controller power source.
- Thread starter Soaring
- Start date
Soaring, I suppose you could, it is only another power sauce. But not really sure why you would want too, you would need to bring a wire through the trailer plug and up to your dash as you still need the controler in the cabin.
It would also make the controller useless for any other trailer in the future, as your controller would have no power when connected to any other trailer other than yours. But anything is possible.
It would also make the controller useless for any other trailer in the future, as your controller would have no power when connected to any other trailer other than yours. But anything is possible.
Thanks for the responses TT and Cracka.
So where Im going with this is I turn over my company car about every 5 months. I don't want to keep installing/removing the controller each time.
I've purchased a male and a female 12 pin plug, and am looking at making a "patch lead" up that sends the indictors and stop signals, aux power etc straight through, and taps into the the brake signal and sends it to the controller in the cabin.
For power & earth I was looking at using a one of the power outlets in the vehicle (cigarette lighter points), however these are only rated to 10A. I figure the max load with a duel axle van would be around 12A. (I'm happy to be corrected here) Hence looking for an alternate source of power (other than a hard wire to the vehicle).
I figure the breakaway brake system use its own separate battery mounted within the van, and that is OK, so why not pick up power from the van battery? Obvously I would have to ensure the van battery has sufficient charge prior to towing, but given I have solar, battery charge shouldn't be a problem.
There are spare pins on the 12 pin plug I could use, or go with an anderson style separate plug.
Good point, that this would limit me to tow only my van, but I've never had to tow anything else up to now, and I see the Tug as being a bigger issue.
So where Im going with this is I turn over my company car about every 5 months. I don't want to keep installing/removing the controller each time.
I've purchased a male and a female 12 pin plug, and am looking at making a "patch lead" up that sends the indictors and stop signals, aux power etc straight through, and taps into the the brake signal and sends it to the controller in the cabin.
For power & earth I was looking at using a one of the power outlets in the vehicle (cigarette lighter points), however these are only rated to 10A. I figure the max load with a duel axle van would be around 12A. (I'm happy to be corrected here) Hence looking for an alternate source of power (other than a hard wire to the vehicle).
I figure the breakaway brake system use its own separate battery mounted within the van, and that is OK, so why not pick up power from the van battery? Obvously I would have to ensure the van battery has sufficient charge prior to towing, but given I have solar, battery charge shouldn't be a problem.
There are spare pins on the 12 pin plug I could use, or go with an anderson style separate plug.
Good point, that this would limit me to tow only my van, but I've never had to tow anything else up to now, and I see the Tug as being a bigger issue.
BTW teh controller is the P3. I noticed in bothe the instructions and the harness, that only thre blue (brake feed) and the Red (power) are thicker gauge, Im guessing 6mm. the earth return is the same gauge as the brake signal wire.
Its been a while since my elec engineering subjects, but current in a circuit is limited by the weakest link. In this case the earth.
Am i missing somethig here.
oe is it jsut becasue the expectation is the eath will be a short run, fixed to sheet metal, close to the controller.....( I do remember somthing in the instrtuctions saying to run directly to the battery negative terminal though, making it the same run length as the power in a standard install.
Its been a while since my elec engineering subjects, but current in a circuit is limited by the weakest link. In this case the earth.
Am i missing somethig here.
oe is it jsut becasue the expectation is the eath will be a short run, fixed to sheet metal, close to the controller.....( I do remember somthing in the instrtuctions saying to run directly to the battery negative terminal though, making it the same run length as the power in a standard install.
All good thoughts, but are you having tow bar and wiring fitted to new car anyway, and therefore brake controller as well as a standard fit assuming that you are running power from car battery to caravan as well. Another suggestion would be to develop specific connectors for the brake controller so that it is easy to remove. Knowing how much of a pain this can be unless you have the same person fit each time is frustrating (especially every 5 months).
On the Electrical Eng side and the wires I think the theory goes like this:
Power circuit for the brakes is from +ve battery through fuse, wiring to brake controller, power lead (red), brake controller, brake feed (blue), wiring to trailer pin, wiring to caravan brakes, brakes and then return through earth (both pin 3, any other ground pins and tow ball if caravan grounded to chasis).
This does not include the earth on the brake controller as there is no earth return from the caravan to the brake controller.
The earth on the brake controller is only for the electronics in the brake controller and will not carry the braking currents. Hence the size of the wire. The red lead is used to supply the brake controller electronics (as well) so a small amount of the current is returned via the brake controller earth.
Sorry for the words rather than a picture.
On the Electrical Eng side and the wires I think the theory goes like this:
Power circuit for the brakes is from +ve battery through fuse, wiring to brake controller, power lead (red), brake controller, brake feed (blue), wiring to trailer pin, wiring to caravan brakes, brakes and then return through earth (both pin 3, any other ground pins and tow ball if caravan grounded to chasis).
This does not include the earth on the brake controller as there is no earth return from the caravan to the brake controller.
The earth on the brake controller is only for the electronics in the brake controller and will not carry the braking currents. Hence the size of the wire. The red lead is used to supply the brake controller electronics (as well) so a small amount of the current is returned via the brake controller earth.
Sorry for the words rather than a picture.
Thx Millers,
Unfortunately, no accessories other than factory can be fitted, HD tow bar with 12 pin is a factory option but not controller.
Not that Im complaining about the new car every 5 months
I understand what you are saying re the wiring. But even the pin 3 wire is small gauge. I don't like the idea of grounding via the ball. Grease, paint on the hitch, and the flopping around of the hitch in the receiver etc does not make for good a circuit.
I think I'll go with an anderson style plug back from the van, both ground and power, and attached the ground to a convenient bolt at the rear of the tug.
Unfortunately, no accessories other than factory can be fitted, HD tow bar with 12 pin is a factory option but not controller.
Not that Im complaining about the new car every 5 monthsI understand what you are saying re the wiring. But even the pin 3 wire is small gauge. I don't like the idea of grounding via the ball. Grease, paint on the hitch, and the flopping around of the hitch in the receiver etc does not make for good a circuit.
I think I'll go with an anderson style plug back from the van, both ground and power, and attached the ground to a convenient bolt at the rear of the tug.
Something else to remember with the brake controller, is your ability to control the van brakes independently of the car, from the drivers seat, if the controller is not in the car you loose access to this important safety feature.
Definitely will have the controller mounted to the dash. I've got a spare fuse box cover I've mounted the P3 to. I'll feed the controller harness from the 12 pin, through the lift gate seal and along the sills to the dash.
Fuse box cover with P3 mounted. 12pin plug and socket. Twin core for stop signal and earth coming from pins 3 and 6. The 6mm lead is the brake wire to pin 5. Just got to get back to Jaycar and pickup some 6mm for the power. Will use spare pin 12, and run a lead to the van battery.
I suppose you will need to make your wiring to suit different models as the Australian Ford Territory's days are probably numbered, so its probably a good idea with what you are doing. I wonder if you could research how caravan hire companies fit their loan brake controllers. I hear the next Territory will be a Ranger 7 seater.
I have a friend who has a similar dilemma, his company cars are Klugers, he has made up a loom and it fits in the spare wheel well, but I don't think that is good as he cant access it in emergency situations.
Cheers Geoff
I have a friend who has a similar dilemma, his company cars are Klugers, he has made up a loom and it fits in the spare wheel well, but I don't think that is good as he cant access it in emergency situations.
Cheers Geoff
cheers Geoff. Quite right, I may need to have this fit other models. What they may be...........
I've done a little research in the hire company side. most seem to have a drawbar mounted controller. Massive pain in the butt. No in cabin control, and you have to stop to adjust the brake settings depending on load.
The other issue is that if you use a controller like a Tekonsha which measures the movement of the tow vehicle to apply braking force proportionally, it would be confused it is in the caravan.
Yep, understood, but the controller is in the cabin, mounted to the fuse box cover on the dash.
Just a thought, don't you also risk the what if factor if the van battery is dead and not charging then you are without brakes?
At least if the car battery is dead you can't actually drive anywhere.
At least if the car battery is dead you can't actually drive anywhere.
:barbershop_quartet_member:
I do have solar, so hoping my van battery should be maintained pretty well.
You do have me thinking now though. What I might do is provide a "T" point for power in where in the unlikely case of dead van battery, I can run a cable into the vehicle engine bay/battery (perhaps out the window and through the hood/fender gap) to provide a temporary power source.
Good point antman. In that case the P3 should tell me prior to driving off right? Either error code, or low voltage to brakes?
I do have solar, so hoping my van battery should be maintained pretty well.
You do have me thinking now though. What I might do is provide a "T" point for power in where in the unlikely case of dead van battery, I can run a cable into the vehicle engine bay/battery (perhaps out the window and through the hood/fender gap) to provide a temporary power source.
Brad while i can see why you are looking at doing this (wish i could have a new terry every 5 months!) i would strongly advise against powering your brake controller from the van battery. As antman has so eloquently put it above you are certainly introducing a mighty what if factor. I know you have solar but on rainy days (just when you need trailer brakes the most) solar output will be very low and if your battery is down to start with having camped all night you may be placing yourself in an undesirable situation. On top of that you are virtually doubling the length of cabling by running from your van to the car and back again so voltage drop will be a real issue. I certainly think you will need wiring larger than 6mm for that sort of run. On top of this you will need to supply the van with between 10 to 20 amp for your fridge ( depends on size) plus adequate power to run the brake unit as well as supply power to charge the van battery and the breakaway battery. remember this is brakes you are talking about not some add on accessory. I would find a way to get power from the car if possible.
Soaring
Brakes are too important to mess around with. Also, in the event of an accident, crash investigators and/or insurance assessors might have a field day, leaving you high and dry
Another option you can look at is getting a Tekonsha wiring harness to suit your vehicle. These are made with the appropriate vehicle manufacturer's plugs to just connect the electric brakes.
Check out this link to the 134 harnesses available for Tekonsha brake controllers.
This would solve most, if not all your issues. Just need a new harness/connector is you change vehicle model/brand.
Cheers,
Rohan
Brakes are too important to mess around with. Also, in the event of an accident, crash investigators and/or insurance assessors might have a field day, leaving you high and dry
Another option you can look at is getting a Tekonsha wiring harness to suit your vehicle. These are made with the appropriate vehicle manufacturer's plugs to just connect the electric brakes.
Check out this link to the 134 harnesses available for Tekonsha brake controllers.
This would solve most, if not all your issues. Just need a new harness/connector is you change vehicle model/brand.
Cheers,
Rohan
Ok, got it sorted. Thanks to boots antman & Ronem for your concerns. Had a chat to the elec eng guys at work today, and while not opposed to the idea bra powering from the van, they did suggest That There is an easy to get to grommet under the passenger side of the dash Through the firewall Witch I can easily run power and earth.
So now the system looks like this. Power direct from battery via above grommet Using supplied 30 amp breaker.
brake switch signal from the trailer plug using 4mm cable (this is actually recommended rather that the brake switch).
the brake supply is a 6mm out through the tailgate, into the adapter 12 pin socket connected to the van. Earth is same routing as power.
so really, what I'm saving with regards to car to car installation is a, connection to the brake switch, and connection of the brake actuation to the car 12 pin. ( this was really the part that was always going to be a pain in the butt.)
This image still shows the power and earth coming from the van as per previous design, but you can see how the brake actuation, and brake signal are being fed back to the controller from the adapter plug/socket.
So now the system looks like this. Power direct from battery via above grommet Using supplied 30 amp breaker.
brake switch signal from the trailer plug using 4mm cable (this is actually recommended rather that the brake switch).
the brake supply is a 6mm out through the tailgate, into the adapter 12 pin socket connected to the van. Earth is same routing as power.
so really, what I'm saving with regards to car to car installation is a, connection to the brake switch, and connection of the brake actuation to the car 12 pin. ( this was really the part that was always going to be a pain in the butt.)
This image still shows the power and earth coming from the van as per previous design, but you can see how the brake actuation, and brake signal are being fed back to the controller from the adapter plug/socket.
This would be the ultimate for what you want http://www.tekonsha.com/content/products.aspx?lvl=2&parentid=1400&catID=1435&part=0 but I don't believe that they have the required rf appro als for australia.