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  Recommendations, Ideas & Parts
  • When selecting your 'Donor" car choose one which is structurally sound with little or no rust.

  • Choose a lighter car as possible to keep the power requirements as low as possible eg. motor size and battery capacity.

  • If you must place holes in the floor or any part of the car body, ensure that these do not weaken the vehicle's structural strength. If holes are near seat or seat belt mountings, they could weaken these mounting points and cause some of the Australian Design Rules (ADR's) to fail on examination.

  • If using lead acid batteries the weight of the batteries should be at least 30% of the vehicle's GVM (Gross Vehicle Mass).

  • Get hold of the book by Bob Brant and Seth Leitman, "Build Your Own Electric Vehicle" - 3rd Edition. This book (352 pages) has a wealth of information about all aspects of vehicle conversion, EV history, batteries, motors, controllers, EV examples etc. The best place to get this book is from www.biblio.com. Prices start from a few dollars for second hand books. Also available from eBay or Amazon
    Make sure you get the latest edition - like the one shown on the right...
    January 29, 2013  0071770569  978-0071770569 3

  • See the links at the bottom of the What Car? page for car specification websites.

  • Batteries recommended are: Lithium Iron Phosphate (LiFePO4).
    Available in Australia from EV-Works who also supply the BMS to suit. 
    To visit the website of the manufacturer: Winston Battery Ltd.


  • The book "Convert It!" by Michael P. Brown is available from various outlets and
     I have found this book to be very good, but a little dated.


  • Hook up with a local Electric Vehicle club - eg. in Australia there is the
    Australian Electric Vehicle Association. Join in and gain knowledge by
    associating with experienced people who may be able to answer your questions.


  • Purchase the DVD "Who Killed The Electric Car?" from the Plug In America website
     for $US10.00 plus post.


  • Purchase the DVD "Revenge of the Electric Car" from the Plug In America website       
     for $US27.00 plus post.


  • Join EVCAST for regular EV Podcasts and discussion groups.   

Protecting the DC-DC Converter from System Power Drain

See PDF or image below for explanation.

This idea came from Jack Rickard (EVTV) after many failures of his DC-DC Converters.

The secret of the whole circuit...

The series diode (D1) prevents the DC-DC converter from supplying power to the rest of the system as the pack voltage droops under sudden load eg. acceleration.


Using a PB-6 Pot Box with a Kelly Controller.

This is normally a difficult situation. Some say to open the PB-6 throttle pot box and connect to the third terminal of the pot. If this is done the controller will work with the PB-6 except that the top speed of the vehicle will be limited to under a third of the speed that would normally be available. This is because of the fact that the pot inside the PB-6 is in fact 20K ohm and not 5K ohm. Because of the limited movement of the actuating arm the pot wiper travels over only 5K ohms of the full value.

I have developed a circuit which will convert the 0-5K ohm from the standard PB-6 (2 wires) to 0-5V to suit the Kelly controller.

I have incorporated two additional features as well:-

  • One is the reverse speed control making use of the reversing switch in the gearbox. This operates a relay and limits the output voltage to much less than 5V. An optional valet switch is also included.

  • The second feature is protection against having 5V applied to the controller in the case of the pot box going open circuit or being partly disconnected, which would normally be full throttle!. This uses a voltage sensing circuit and another relay to reduce the output to 0 volts if this happens. This can only be reset by turning the car off and on again.

In actual fact the output from the circuit I built is 0 - 4.65V but this is close enough as the Kelly setup allows for this in the configuration program.

The 0-5V circuit is powered from a 12V isolated supply which I use to power the Kelly controller internal circuitry. I have included the circuit in JPG (190Kb) and PDF format (2.7Mb).
There are more notes on the actual circuit to explain some of the component choices. This is a hand drawn circuit only - no excuses.

NOTE: I take no responsibility for the resultant construction by any other person.

PS. Someone claims that the true Curtis brand PB-6 pot box actually has a reduced travel (40 degrees ?)
      5 K ohm pot inside. If someone could verify this I would be pleased. If this is the case all three
      terminals could be used as a potentiometer to produce the 0-5V output. It will still work in the
      circuit below with two terminals to take advantage of the open circuit protection.

0-5K Ohm to 0-5Volt converter  (Reduced JPG version)
(Updated 14 March 2009)


Using the Standard Tacho in an Electric Car.

I found a circuit on the the net, shown in an article in Silicon Chip (Australia) magazine September 1997, page 30 and 31, and have modified it to work between a Hall Effect pickup and the original standard tachometer which did rely on high voltage pulses from the original engine ignition coil terminal.

The circuit presented here supplies those high voltage pulses required by the tacho.

Available as PDF.

For an original 4 cylinder (4 stroke) engine you need a soft iron (steel) disk with 2 slots, each slot at least longer than the width of the Hall Effect unit (approx 20mm or 3/4inch) evenly spaced.
For a 6 cylinder: 3 slots ...etc..

The Hall Effect device that I used was from Jaycar: ZD1900 which is a HKZ-101 or similar.

Design for Lead Acid Battery Box Control/Timer.

Please note that this was designed for use with Lead Acid batteries mounted within the vehicle cabin.

      ...it was obviously not used in the EVRIC EV (which is Lithium Iron Phosphate powered).

Please use/modify the design as you wish. The circuit presumes that you have a +12Volt signal available when the batteries are being charged (C).
NOTE: I take no responsibility for your construction of this design.

The Australian regulations for charging Lead Acid batteries, which are in the cabin of the car, requires the installation of sealed/vented battery boxes with fan forced ventilation. Part of the requirement is that the fans stay on for a period after the charging is completed or turned off. (Input C)
The regulation also requires the fan(s) to be running while the car is being driven. (Input D)

This design allows the fan(s) (F) to remain on for 2 minutes after the charging circuit has been turned off.
This ensures that any gasses present are removed from the battery box.
The 2 minutes may have to be varied depending on the size of you battery box and the air movement of the fan(s).

This unit was designed on a PCB which fitted into a JAYCAR box HB6014,(130 x 67 x 44mm).

Eric Rodda

Download A4 PDF here                Reduced size JPG shown below.

Using a diode from a diode bridge to connect a DC-DC converter to a 12V aux. battery
to prevent the DC-DC Converter from draining the 12V battery.


Download PDF here



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