openinverter forum

Hello, OpenInverter world!

Intro:
I am new to the EV world, but not technology and cars. I am here because I am interested in learning more about the inner workings of the different EV components and ultimately build my own EV. I am an IoT geek and have been digging into CAN bus lately for fun, along with many other projects. No stranger to a soldering iron, programming, and SBCs.

Shoutouts:
I would like to shout out to the following people who have provided great videos and information that has helped me visualize what is needed in a good EV build and what challenges to expect:
Zero EV - Great videos of the process of building the MX-5 kit, very professional!
Jon Volk - I grew up with an E30 BMW and have a soft spot for them. Very impressed with the performance you have gotten out of yours!
Electric SuperCar - I was exploring the idea of a kit car EV. Great videos showing the build process.
And of course, Damien Maguire! I was thinking to myself "the BMW 8-series is a modern classic and would make a great EV" before I stumbled across your videos and this community!

Goal:
I am looking to build an EV with good performance (sub 5 second 0-60) that I can use a testbed for future projects. I am hoping to start building the electronics part (motor, BMS, charger, etc.) without a vehicle first and with a modest (a.k.a. wife-approved) budget. As the single component that is quite expensive and also "expandable" in some sense, is the battery, I am thinking of starting with good parts all-round, but very few batteries during the initial build. Once everything is sorted out, I will start increasing the battery count to increase range. I'm still making a list of possible cars to convert, ranging from C3 Corvette, BMW E31 8-Series, and even FFR 818 kit.

Components:
Motor: Tesla LDU ($4000)
Inverter: OpenInverter Tesla LDU Community Edition ($400)
BMS: Orion BMS 2 24-cell + Accessories ($1000)
Charger: Elcon TC HK-J 3300W Charger ($600) or StealthEV options? ($1000-$2300)
DC-DC Converter: ?? No need if I pick StealthEV options
Batteries: ??

Questions:
Chargers + Batteries: Correct me if I'm wrong, but it seems that when picking a charger, I need to have planned out my battery pack's total voltage. If I want to get full power out of a Tesla motor, I will need to be in the ballpark of 300-400V. I have been looking at different battery options that people have used, like Tesla S modules, LG Chem, and custom CALB CAM72 modules. If I start with fewer batteries, will I have to change chargers once I add more batteries? Ideally, I have a small capacity pack (in series) with high voltage, then add more in parallel for more capacity. Beyond Elcon and StealthEV, are there any other options I should consider?

LG Chem Batteries: I have not been able to find this anywhere. What search term should I be looking for? They are apparently 60V, so much easier to reach +300V.

Controller: Regarding the inverter board, is it a direct link between that and the throttle? Or is there a controller I need to take into account?


Anyways, thanks for making this far into my first and probably largest post! Hope to get to know everyone here better and contribute my findings once the project begins!

- Costas

Welcome!

Where are you located? Please add this to your profile so others can help with more localized resources. (Ie the US, EU, EMEA)

The LGs have been pulled from the market from a Cease and Desist letter from LG. I do have 6 of them. I'm planning on using them with SimpBMS and Chevy Volt (LG made) BMS modules. I also liked that I only had to buy 6 modules. The downside is I probably should have bought 12.

There are much higher powered Tesla chargers out there (that unfortunately need some modifications to run the OpenInverter / EVMBW controllers), but at significantly cheaper than StealthEV...

Inverter board can be set up for CAN throttle, or direct input.

-Matt

Thanks Matt!

I updated my profile, I'm in Houston, Texas. So far I haven't found any EV related resources here. The closest is Moment Motors in Austin, a 3-hour drive.

I will look into a Tesla charger with the OpenInverter PCB. Any idea if that will charge CALB batteries, should I go that route?

Tagging into this because CostasV has said exactly what I'd have hoped to have said - but I'm considering Ideally two SDUs.
Very best of luck Costas, I'm on the other side of the Atlantic, but your build seems similar to my own aspirations - so I'm extremely keen to follow along from afar.
Very very best of luck,

I know it's been a while but I'm a complete newb as well and interested in how this has progressed. Similar aspirations to mine but mine's an E30 (not as skilled as jon!)

Hello Costas,

It's great to see your enthusiasm for building your own EV and your thorough research into the components required for your project. Let me answer your questions :

Chargers + Batteries:
You're correct that your battery pack's total voltage will determine the charger you need. Most EV components, including the Tesla motor, work efficiently within a specific voltage range. If you plan on starting with a smaller capacity pack and expanding it later, you might need to consider a charger that can handle both the initial and expanded voltage ranges. Some chargers can be adjusted to accommodate different voltages, while others might require a change if your voltage range changes significantly. Both Elcon and StealthEV are reputable options, and you could reach out to them directly for guidance on your specific setup.

LG Chem Batteries:
LG Chem offers a variety of battery modules suitable for EV conversions. To find information on their EV-specific modules, you could search for terms like "LG Chem EV battery modules" or "LG Chem lithium battery modules for electric vehicles." Keep in mind that the specifications and availability may vary over time.

Controller:
The inverter board you mentioned is responsible for controlling the electric motor's speed and torque. Generally, EVs have a motor controller (inverter) that interprets inputs from various sources, including the throttle pedal, and then adjusts the motor's behavior accordingly. You will likely need a separate controller unit that interfaces with your inverter and manages aspects like regenerative braking, traction control, and communication with other vehicle systems. The specifics depend on the inverter and motor you're using, so consulting the documentation provided with your chosen components will be crucial.

It's clear you've done your homework and have a solid plan in mind for your EV build. Remember that EV conversions can be complex projects, so taking your time to research and plan thoroughly will pay off in the long run. Feel free to reach out to the EV conversion communities, like OpenInverter and other EV forums, for more specific advice and experiences from fellow enthusiasts. Best of luck with your project, and I look forward to hearing more about your progress!

Also note that there are many more options these options that I have mentioned are from my mind. Please keep us updated on what is happening.

Good time ahead