I am a partner in an Electric Vehicle Conversion and Parts company, REVOLT Custom Electric Vehicles. So far that has involved designing custom electronics to interface standard components to the vehicle systems.
Our first project was to reverse engineer all of the CAN communications in a Mazda 3. Certain communications from the engine computer (PCM) are required to make the dashboard and power steering system operate correctly. On the Mazda (and most Ford products I've seen) the PCM is part of the engine wiring harness which connects to the car in only one place. This probably makes it very easy to offer different engines in the same vehicle. In our case it made it easy to connect our electric drive system to that one connect. I designed a small PCM around the Microchip PIC 18F2580 processor with integral CAN controller. The PCM listened for certain messages on the bus (like speed, Air conditioning on, and anti-theft), and gathered data from the electric drive system. It then sent messages that updated the odometer, speedometer, tachometer, radiator fan and many other systems. The net effect for the driver is that the vehicle behaves exactly as it did from the factory. For us very little modification of the dash area was required, it is largely a "plug in and go" conversion.
Laying out circuit boards, and designing software is fairly straightforward.. I've been doing hobbyist electronics work since I was about 12. I like to think I'm not half bad despite my lack of a Electrical Engineering degree (I graduated with a Computer Science degree instead). Oddly the biggest problem I face is connectors.
In the hobbyist EV world elevator screw terminals, or faston connectors are the norm. They are both inexpensive, but neither is really vibration resistant enough to trust in an automotive environment. Both also involve having holes in the enclosure where water could potentially enter. I've been looking instead for a connector that is PC Board mount, but can penetrate the enclosure shell in a water resistant fashion. Ideally the mating (wire side) connector should be easy to assemble, since I expect my customers will have to do that part.
As it turns out, there are only a few options.. most water resistant connectors are wire to wire, not wire to board. The best I've seen so far are the Molex MX-150 line. Its rapidly turning out to be a "designing the circuit is easy, designing a complete package with connectors and enclosure is hard". No wonder most EV parts suppliers don't sell electronics in enclosures.
Our first project was to reverse engineer all of the CAN communications in a Mazda 3. Certain communications from the engine computer (PCM) are required to make the dashboard and power steering system operate correctly. On the Mazda (and most Ford products I've seen) the PCM is part of the engine wiring harness which connects to the car in only one place. This probably makes it very easy to offer different engines in the same vehicle. In our case it made it easy to connect our electric drive system to that one connect. I designed a small PCM around the Microchip PIC 18F2580 processor with integral CAN controller. The PCM listened for certain messages on the bus (like speed, Air conditioning on, and anti-theft), and gathered data from the electric drive system. It then sent messages that updated the odometer, speedometer, tachometer, radiator fan and many other systems. The net effect for the driver is that the vehicle behaves exactly as it did from the factory. For us very little modification of the dash area was required, it is largely a "plug in and go" conversion.
Laying out circuit boards, and designing software is fairly straightforward.. I've been doing hobbyist electronics work since I was about 12. I like to think I'm not half bad despite my lack of a Electrical Engineering degree (I graduated with a Computer Science degree instead). Oddly the biggest problem I face is connectors.
In the hobbyist EV world elevator screw terminals, or faston connectors are the norm. They are both inexpensive, but neither is really vibration resistant enough to trust in an automotive environment. Both also involve having holes in the enclosure where water could potentially enter. I've been looking instead for a connector that is PC Board mount, but can penetrate the enclosure shell in a water resistant fashion. Ideally the mating (wire side) connector should be easy to assemble, since I expect my customers will have to do that part.
As it turns out, there are only a few options.. most water resistant connectors are wire to wire, not wire to board. The best I've seen so far are the Molex MX-150 line. Its rapidly turning out to be a "designing the circuit is easy, designing a complete package with connectors and enclosure is hard". No wonder most EV parts suppliers don't sell electronics in enclosures.
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