Question on breakaway battery monitors

Here is an extract from the NSW Vehicle Inspectors Bulletin
Requirements for large trailers equipped with electrically operated brakes
"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."


My reading of the requirement is that an energy source (battery) is required in the trailer but not necessarily a separate dedicated battery.
However that energy source (battery) must be maintained in a fully energised (whatever that means !!). It is stated that this requirement can be achieved by charging from the towing vehicle.
I am not sure that if solar panels on the van were the only means of charging the battery the requirement would be met. - If you were driving at night, there would be no charging of the battery even though you may be OK due to the 400Ahr capacity of your system.


Ken

Thanks Ken. Your words are encouraging. I have a 60 amp dc-dc charger from the tow. I guess I'll have to check with the inspector.
Keith

Hi Keith,

Yes, in NSW you need a monitor that checks the breakaway battery voltage. I had a simple hard-wired monitor (via a single wire through the trailer plug to the dash) but replaced it with a Hummingbird wireless monitor. It costs considerable more but there are no wires to put through the caravan or tow vehicle and it can monitor several batteries, not just the breakaway, in a colorful display with user-set alarms. In my case I monitor the vehicle's main battery, my deep-cycle secondary battery as well as the caravan's main battery and the breakaway. Small transmitters are connected to the batteries (but not the vehicle's main vehicle battery because it is monitored via the Hummingbird's power supply, say the vehicle's cigarette lighter socket). The transmitters' range is pretty good, maybe 50 metres or more.

Cheers, Mark

Keith, a separate battery should be required. Many units for breakaway systems actually incorporate a battery monitor so there is no need to install one. I have one on the tandem trailer very similar to this unit on fleabay.

Breakaway Battery

As a side issue, one of the main problems with plugging a Bluetooth wireless monitor onto those small batteries is the drain. It may be only milliamps but over a period of months it will drain the battery if it is not connected through your vehicle plug or charged regularly. On a 400A/H, not a worry but a small 4 or 6 A/H, mate it will be dead flat in no time.

Cheers,

Mick

I read the extract carefully. Itstates : It is essential to have the battery on the trailer, but not essential to have the charging system on the trailer. It is satisfactory to have the charging stystem in the tow vehicle. Now if this second phrase was not included, the rules would demand the charging system be on the trailer too. Therefore by having the charging system on the trailer you have met and exceeded the requirement.

That just about settles it. Thanks everyone for your help.
This is a great forum for getting informed and sensible answers.
Thanks again,
Keith