The minimum requirements for breakaway devices is set down in the Vehicle Standards Bulletin VSB1 you can read a copy
here. . On top of these minimum federal requirements each state has the power to impose additional requirements as well so it is important to check with your relevant state department.
A good guide is also available on Alko's site
here
So in short we need
A self contained power source capable of powering the brakes for at least 15min.
A means to keep that power source charged
Which one of the following methods you employ may vary with the type of controller in use. you will need to have a look at the install documents to make sure.
All of the units will have a provision to charge the battery from some sort of external source and that is where you will likely need to connect your charge wire to. In most cases this will be directly to the battery but may vary for units with some form of battery monitoring. In my diagrams I will just show the connection directly to the battery for simplicity.
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Use a 240v charger to keep the battery topped up. Yes a bit obvious but for those that have access to 240v this will be the quickest way to go. You will need to get a charger that is made to be connected to the battery for long periods of time without overcharging the battery. You can get dedicated breakaway chargers from specialty caravan shops and also most of the chargers meant to keep 12v alarm batteries topped up will work as well.
No drawing needed really just plug it into a power point and connect it to your breakaway battery.
The advantage to this method is with use of the correct charger your breakaway battery will be maintained at a high state of charge. It will be kept separate from your van battery so any faults in that setup will have no effect on your breakaway battery.
On the down side you will need access to 240v and if you choose not to hard wire it in place you will have to remember to plug it in when needed. Also your breakaway will receive no charge when you are disconnected from your tug and camping off grid. I don't see that as a major problem though.... unless you are camped out for a few months trying to avoid an alien invasion or the tax man etc.
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Use a small portable solar panel to keep the breakaway battery topped up.
Again this method will keep the breakaway well charged and separate from the van system. if you fit a lead with a plug to your breakaway battery it will be a simple operation to connect up when needed.
no real downsides to this method that i can see, other than the initial cost to setup. That shouldn't be very much.
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Connect your breakaway battery to your vans battery system and use the charging output from the setec and or van solar to keep the breakaway topped up.
Advantages:
The setec is well suited to providing a long term charging solution. Your breakaway battery will be receiving a charge any time the van is hooked to 240v and if you have solar on the roof any time they are in the sun.
disadvantages:
240v required if no solar installed
Your breakaway battery will be directly affected by your van batteries state of charge. so if you are camping off grid and managed to flatten your van battery you will take your breakaway battery down as well.
Your van battery will be directly affected by your breakaway system any problems there may also cause problems for the van.
If your breakaway switch is activated the van brakes will draw power from both batteries. While this will certainly mean the brakes will stay on for the required 15min it could also cause possible damage to the brake activators if they are not rated to be held on for very long periods of time. Depending on your van battery size this could be many hours.
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A variation on the above would be to add a blocking diode to the positive line. This will now stop the van system from draining the breakaway battery. A good safeguard to ensure your breakaway battery stays charged even if the van system is flattened.
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Remove the breakaway battery all together and just hook up to the van battery. The major advantage here (getting rid of the annoying breakaway battery) is also the major disadvantage as your breakaway now will rely totally on the van battery. Any problems there and your breakaway will be out of action. If you do a lot of off grid camping you would need to have some means of keeping the battery charged up. Not sure how this would go with the in car battery monitor required in NSW.
With all of these methods you will need to be sure the breakaway does not get activated by accident while the van is sitting. That will be the biggest down side to hooking up to your van battery system.
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If you have Solar installed in your van you could also fit a second small regulator and use it as a dedicated breakaway charger. Of course this will be of no use if the van is stored under a cover or in a shed.
So there you have it , a few ideas to think about. Sorry it is all a bit rough but am busy this weekend installing all the bits into my new tug.
Comments, suggestions and constructive criticism always welcome
shane
HI all, is is the unit i have with one small wire coming off it, wheres the battery you speak of ? , is it inside the unit ?
