Project Parts

WARNING  boring technical post

Australia Post has been delivering more of the components I’ve purchased for one of my projects.  Many of the components are coming from China via eBay.  I did look at sourcing the same items in Australia, however it didn’t take long to realise the cost usually increased by approximately 500%.  We frequently hear the expression “Purchase locally and buy your children a job!”  But, like me, the local sellers are purchasing from China and then adding a massive margin.  I’ll buy local when it’s value for money or the quality is superior.

This particular project is to add a number of components to our new Isuzu 4x4.  They include:

• Tyre pressure management system
• CB radio
• Trailer electric brake controller
• LED light bar
• Dash camera
• 2nd battery charging system
• 12V charging power to a camper trailer
• Additional usb charging ports

The power supply for the trailer electric brake controller must be directly wired to the vehicle starter battery without a fuse.  Not having a fuse is unusual, but the logic is you don’t want the brake controller to fail when towing a heavy trailer because a fuse ‘blew’.  The purpose of any fuse is to protect the cable from overheating or failing, so I’ll run a high capacity cable between the battery and brake controller in an effort to ensure there are no safety issues.

Apart from the dash cam, the remaining components will only be able to be turned on if the engine is running or the ignition key on and turned to Accessories.  The dash cam will be powered 24/7.  This is because the dash cam has an automatic ‘bump’ recording mode. (ie, it will automatically start recording if the parked and unattended vehicle is bumped or knocked).  It’s unlikely the dash cam will draw enough power to flatten the started battery during the time the vehicle is unattended.  However to avoid the possibility any of these “accessories” might flatten the vehicle starter battery I am going to fit a voltage sensitive relay (VSR) between the starter battery and these additional components.

Essentially the VSR is an automatic switch which engages when the starter battery voltage reaches 13.3V and then disengages if the starter battery voltage drops below 12.8V.  So the VSR serves two purposes.  It ensures the starter battery is charged first and then it protects the starter battery from being discharged below 12.8V.  So using the VSR will prevent my accessories from inadvertently draining the starter battery.  Obviously I don’t want to be stuck in the middle of the Great Sandy Desert with a flat battery.

The TPMS and dash cam arrived from China last month.  I have yet to buy the CB radio, LED bar and brake controller.  However the plan is to install all the wiring and then fit these three items later.

So what items have I received.

From top right clockwise

• 125A circuit breaker which will fit between the starter battery and the VSR
• Two 20A circuit breakers for the main power supply to the accessories
• Voltage Sensitive Relay (VSR)
• Soldering jig and magnifying glass (old eyes and shaky hands)
• 1m of flexible curtain cable to act as a ‘draw cord’ to feed the wiring through the back of the dashboard
• Range of cable terminals.
• Switch holder (below VSR) which will hold four switches.

Yet to be received

• 12V fuse panel
• Switches
• Cable and lugs

I remember the first car I owned.  It was a 1967 Vauxhall Viva and there was oodles of free space under the bonnet.  After looking under the bonnet of our Izuzu I can see it’s going to be interesting trying to squeeze in some of the above components. 

My tools haven’t yet arrived so at least I have time to think through this problem!

The media server project has also come to a halt whilst we wait on our UK boxes.  One of these contains the computer hard drives.  The boxes also contain my woodworking tools which means no progress on the bed project.