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Discussion Starter · #1 ·
Hi, I've been browsing this forum for several years, been inspired by many of the people on here including MoltenMetal and Baratong because of their work on Triumphs, and joined a few months ago when I decided to embark on my own project. I have minimal experience working on cars, but know a fair bit about the electrical side of things, have worked with plenty of small electric motors and controllers before, and am motivated to learn. My goals are to create a fun, weekend car that can last me for years to come, as well as to learn hands on as much as I can about electric cars and the systems involved since I'm less than two years out of a computer engineering degree and hope to work in the electric car industry in the near future. Luckily I know several longtime mechanics who have been giving me guidance and help as needed. About six months ago I picked up a 1974 Triumph TR6 without an engine in it, but with a solid body and a frame with minor rust. Since then have stripped all the parts, removed the body shell, sandblasted all rust off the frame, and am about to repaint it before putting the body shell back on. I also just got a Vitesse Mazda transmission kit to install and am going to get help rebuilding the differential. Once the body shell is on, and the transmission and diff are back in I'll be ready to start converting it.

Here's my current plan:
For major parts I plan to use:
- A NetGain Hyper9 motor
- 5-7 Tesla 5.2kWh battery packs from HSRMotors (Still need to build mockup cardboard batteries to test fitment)
- An Orion BMS 2 (either 36 cell or 48 cell)
- An Elcon 3.3kW charger (I may replace this and the DC-DC converter with a Stealth EV all-in-one 3.3kW charger and 1.0kW converter, but curious about everyone's thoughts)
- An Elcon 1.0kW DC-DC converter
- Likely a Tesla pump to pump coolant through the batteries, may end up using two since I'll likely have the batteries split between the front and back and not sure if it is smart to plumb cooling lines through the center of the car.

For safety controls I plan to implement:
- An inertial switch between the battery and controller
- A microswitch on the brake pedal to cut acceleration when the brakes are pressed
- Might also add a circuit to prevent charging if the battery temperature is too low, though I'm not sure if charging when the temp is too low simply doesn't work or can cause damage

I have a good idea of how those parts will be wired together, but there is still a lot that I'm currently figuring out. I'm sure with time I'll be able to find the answers on my own, but any help would be appreciated. Some of these issues may seem basic, but this is my first electric car build.

Here are the main things I'm currently trying to figure out:

- What the best solution is for the accelerator pedal voltage output. I see a lot of options available, but not sure which is the easiest to implement and which is most reliable.

- I'm having trouble deciding how to size my battery system for the motors/motor controllers packages I'm looking at, and my current thoughts are based on assuming that the Vmax of my battery system cannot be higher than the Vmax of my controller, but if these controllers are built to accomodate more headroom or there's a way to drop the input voltage to the controller without wasting power that would make decisions a lot easier. The standard Hyper9 has a max voltage of 132V, and the high voltage Hyper9 has a max of 180V, and the batteries I'm primarily looking at are 22.2Vnominal and 25.2Vmax. Using 5 batteries in series would yield 111Vnominal and 125.2Vmax which would work well for the standard motor, but only provide 26kWh of battery. 6 would give 151.2Vmax and 133.2 Vnominal which exceeds the 132V max of the standard controller, but with the HV controller at Vmax and max controller amperage (500 amps), the output would be over 12kW less than the max the motor can produce. 7 give 176.4Vmax and 155.4Vnominal, which would be perfect for the HV motor/controller, but then prices creep up fairly significantly from a 5 battery, standard controller option. Is there a way I can make the 6 battery, 31.2kWh system safely provide max output to the standard motor/controller, or are my best options to either use 5 batteries with the standard motor, 7 batteries with the HV motor, or find different batteries?

- While I ultimately want to try to utilize as many stock gauges as possible, I first want to also add a display system either with a screen or gauges to show basic information such as temperatures, charge state, power output, and BMS errors. I'm still determining the best way to do this, especially since I'd ultimately like to make it a fold-away display to make the interior look stock.

- I'm not sure which fuses will be best to use in order to get something that works without overpaying, and am curious what most people here use.

- As well, I could easily implement logic controls for a battery heater, pump, and DC-DC convertor using an Arduino or similar device in conjunction with relays, but I'm curious if there's any better, more common solution for this.

Overall I'm estimating that the above plans will cost between $15,000-$18,000 more depending on which option I go with for my battery system and motor/controller. While less is of course better, the budget is fairly flexible and can be expanded a bit if needed.

If anyone has any advice on ways to implement the things I'm still figuring out, suggestions for things I should do differently, or ideas such as safety circuits I'm missing, I'd truly appreciate it.
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