A Rough Plan
Hey Electrified Miata (the eMiata name was already taken) team, here's where we are at.
Let me first paint the vision for the Electrified Miata. I want to build electrified miatas in various performance levels, all the way from pedestrian to face ripping. To that end, I purchased 2.5 Leaf motors. One Leaf motor weighs 126lbs and its inverter weighs 36lbs. Here's Kurtis and his EV grin helping weigh the beasts
I've also ordered 1000 LG MH1 18650 3200mAh 10A batteries.
Before we can run (or face rip) we must walk and before we walk we crawl (pedestrian). So, our first pedestrian task is to see if those Leaf motors run or not. An intermediate step to the Leaf's spinning is re-purposing our old electric go-kart as a test prototype.
Very lucky for us, someone has already figured out the magic required to make a Leaf motor go. Even spinning the motor is not as easy as it looks. First we need a power source of 140Volt DC at around 10 amps. Then a 12 volt source, which I have thanks to Korey and his motor cycle upgrades. We also need to be able to send and receive Controller Area Networks (CAN) messages to the inverter. We're at the point where everyone can help on this project.
The tasks in no particular order where help, advice, and/or experience would be greatly appreciated are:
1. Assemble two battery packs in a 20S20P configuration. That is 20 cells in series, each of those comprising of 20 cells in parallel. These packs will do double duty. They will be used on our electric go-kart for battery pack and Battery Management System (BMS) stress testing. The completed packs can also be put in series to power a Leaf motor.
2. The go-kart needs to be re-assembled and the Alltrax 7245 controller needs re-programmed to 72 volts.
3. The BMS will need some assembly. I've never done SMD (Surface Mount Devices), I could use some guidance on how to assemble and where is the best place to order circuit boards.
4. Separate the wire looms on the Leaf hardware to have just the inverter and the required motor resolver interface. Below is the current situation.
There is only one motor connection needed, although the inverter needs 12 volt power, battery mains, and CAN interface connections.
5. Develop hardware and software needed to communicate via CAN with the motor inverter. I have a few BeagleBone Black's and a few raspberry Pi's computers sitting around that should be capable of that with a little bit of extra hardware. I also have some python examples of CAN code. Getting that all working should do the trick, although I don't know what it means to acknowledge a CAN message so more research will be required.
Getting the Leaf motor to turn under software control - sounds pretty easy, right? No, not really, but I've found when multiple people get together, it becomes a whole lot easier and usually quite a bit of fun. Looking forward to meeting with everyone who is interested. Leave me a message with how to contact you and I'll let you know the details of when and where. If you aren't in the ATX area you and your expertise are welcome to join us virtually.
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Bill likes cars that understand the 'go fast now' pedal