Jump to content

Recommended Posts

Posted

Hi all, Went to register my boat trailer last Friday and assumed all would be easy , have just replace the complete electric brakes and new bearings on front axle, new disc pads for the over ride brakes , near new tyes, all electrics working fine after sparkie fixed the turn signals on friday , so this should be a piece of cake, NOT QUITE SO!!!

Apparently since 2007 there has been a requirement for a"state of remote battery charge"" warning system to be fitted to any tow vehicle of trailer over 2 tons, I should also note that for the record this is ONLY a NSW regulation!!!!

I have attached below a copy of bulletin 6 and highlighted the relevent parts,

Now you really need to get your head around this , whenever the trailer is attached to the vehicle the battery is under charge from the tow vehicle(12 volts) so if you take a reading at the battery it will say 12 volts , any way the good news is that there is a company in SA that has produced a warning system for this purpose!!apparently they were aproached by RTA NSW to make this item and we will make it law to have it fitted!!!!!!!!!!this is what they told me!!!!!

so the good news is there is such a system , this system elecronically disconnects the charging stage of the remote battery whenever the brakes are applied the sends a state of battry charge signal to the warning box. But wait theres more good news, this system is only made to suit this companys breakaway brake system and you guessed it that system is not fitted to my trailer!!!! the end result will be that i will need to fit a new breakaway system and associated warning kit, sorry dont forget the decal!! about 400 bucks and fitting. :ranting2:

cheers snr

copy of vehicle inspectors bulletin 6 november 2007.

This bulletin is issued to clarify the minimum requirements and to outline the testing procedures for electric braking

systems fitted to large trailers.

The Road Transport (Vehicle Registration) Regulation 2007 requires that all trailers with a Gross Trailer Mass (GTM)

exceeding 2 tonnes be provided with a braking system which will operate automatically and promptly upon breakaway

of the trailer from its towing vehicle, and that such application should be maintained for at least fifteen minutes.

Such trailers, if fitted with electrically actuated braking systems, must be equipped with a device which applies the

brakes in the event of a breakaway from the towing vehicle and maintains application for at least fifteen minutes. It is

essential therefore, that an energy source, such as a battery, be carried on the trailer and that means be provided to

ensure that the battery is maintained in a fully energised condition. In this regard, it will be satisfactory if any trailermounted

battery is constantly charged by the towing vehicle and a warning device is fitted to warn the driver (from

the normal driving position) if the trailer battery charge falls to such a level as to render the trailer brakes incapable of

meeting the requirements.Trailers required to be fitted with breakaway systems are not registerable if there is no means for maintaining the

breakaway energy source in a fully-energised condition (for example, if a charging and warning circuit is not fitted). An

acceptable warning circuit must incorporate either a visual or an audible warning device.The earthing system between the electric brake units and the trailer chassis must be by an earth wire and not via

suspension components or wheel bearings.

In order to vary the trailer braking effect in unison with the towing vehicle, some trailer brake controllers use a

pressure sensing device fitted to the towing vehicle’s brake system. The controller and its connections should be

examined for any hydraulic leaks. If the vehicle is subject to ADR31/--, Hydraulic Braking Systems in Passenger Cars

or ADR35/--, Commercial Vehicle Brake Systems, installation of the control unit must not change the design of the

towing vehicles’ braking system. In particular, all the functions of the dual circuit system must be retained.

Whenever a trailer is presented for inspection, the towing vehicle must be equipped with a compatible charging

system which is connected to the trailer and is fully operable. Any vehicle not so equipped must be rejected.Any trailer equipped with electric brakes, must have a label affixed which states that ... any towing vehicle must be

equipped with an acceptable charging/warning circuit.Test procedures for electric brake systems are outlined on pages 2 and 3.

Posted (edited)

Essentially the warning system would not be that complex, you monitor the trailer battery voltage, compared to the incoming from the car and if the car voltage disappears or battery voltage drops you signal an alarm. 2 stages would be better, one for loss of charge voltage and another for low battery.

The break away system would not be difficult either. A simple solution would be to provide a looped circuit through the trailer adapter with a relay held open by the current, when current disappears on break away, the relay is closed and switches power to activate the brakes.

I did a search on an electronic supplies site and they have voltage sensor kits for around $20 and 20-30A automative relays for under $10. PM me if you want some more details. This assumes you want to tackle the job yourself of course. Sometimes it's just easier to get it done professionally :)

Edited by EmptyHooks
Posted

Essentially the warning system would not be that complex, you monitor the trailer battery voltage, compared to the incoming from the car and if the car voltage disappears or battery voltage drops you signal an alarm. 2 stages would be better, one for loss of charge voltage and another for low battery.

The break away system would not be difficult either. A simple solution would be to provide a looped circuit through the trailer adapter with a relay held open by the current, when current disappears on break away, the relay is closed and switches power to activate the brakes.

I did a search on an electronic supplies site and they have voltage sensor kits for around $20 and 20-30A automative relays for under $10. PM me if you want some more details. This assumes you want to tackle the job yourself of course. Sometimes it's just easier to get it done professionally :)

Impressed, EmptyHooks, very impressed.

Tuffy

Posted (edited)

Thank Tuffy but I'm not that clever. I just realised I forgot to ask an important question. Is the break away for complete separation from the tow vehicle or just the loss of hitch when the safety chain takes up the load? The trailer jack might not pull out when the safety chain is holding it. If the safety chain is holding it you wouldn't want the trailer brakes to lockup, depending on the mass of the boat it could drag the ass of your car all over the road (or off it altogether).

Edited by EmptyHooks
  • 3 years later...
Posted

I know this is an old post, but having just gone through the rego process it reminded me of how I solved this and I thought I'd contribute my experience for any newcomers.

Yes, the Brakesafe system apparently meets all RTA specs out of the box, but I was quoted about $450 for the unit and another $500 for installation. Seemed steep especially since the unit replaced a lot of what I already had and which was working - the breakaway system and the trailer battery charging circuit.

What my rig missed was the monitoring system so I went down the path Emptyhooks outlined. The specs state that the warning circuit can be visual - I opted for a digital voltage meter mounted on the dash and visible from my driving seat. In normal driving operation this meter reads the charging circuit voltage, when I press the brakes a relay disconnects the charging circuit and the meter reads the trailer battery voltage.

The rig passed rego again today.

If anyone is interested PM me and I will send you the details of the Auto Electrician that wired up my rig. (I am not sure if I am allowed to post his business details here outright).

Posted

Yes. All trailers that exceed GMT 2T need brakes that come on if the trailer separates away from the car. These brakes are usually electric so there is a battery that powers the breakaway unit in the event of separation from the tow vehicle. My breakaway unit is a Hydrastar electric Hydraulic system that drives 4 disc brakes.

Full RMS specs are here: http://fullnulled.com/doc/pdf/download/www__rms__nsw__gov__au--registration--downloads--vib_06_-_guidelines_for_light_vehicle_modifications_nov_2007.pdf

Posted

Looks good. I guess if I was starting from scratch with a naked trailer I'd go for this or the Brakesafe I mentioned before, but when the existing rig works, but it needs a few tweaks to stay compliant a different set of criteria come into play. Still have not got to the stage where cost is not an issue.... sadly.

Posted

Ok can anyone help with my question. Can you have mechanical brakes on the four wheels. Mine work fine on the front two wheels,and i dont think the rms states you have to have electrical brakes.

Posted

No, and as stated if the BMT weight is over 2T you need electric break-away brakes that use hydraulic lines to the calipers.

Posted (edited)

Hi AT SEA, quoting from the RMS spec sheet for electric brakes - for which I posted the link above, this is what it states:

"The Road Transport (Vehicle Registration) Regulation 2007 requires that all trailers with a Gross Trailer Mass (GTM)
exceeding 2 tonnes be provided with a braking system which will operate automatically and promptly upon breakaway
of the trailer from its towing vehicle, and that such application should be maintained for at least fifteen minutes.

Such trailers, if fitted with electrically actuated braking systems, must be equipped with a device which applies the
brakes in the event of a breakaway from the towing vehicle and maintains application for at least fifteen minutes. It is
essential therefore, that an energy source, such as a battery, be carried on the trailer and that means be provided to
ensure that the battery is maintained in a fully energised condition...."

The text in blue is the generic requirement. The easiest and cheapest way to comply as Huey says is with an electric/hydraulic system that has a battery on the trailer as the energy source. I guess you could also comply with compressed air brakes and have a compressed air cylinder on the trailer, much like truck trailer braking systems - but that would be mega bucks. I don't think there is a way you could comply with mechanical over-ride brake systems.

Edited by zmk1962

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...