The openinverter project mainly aims to reuse existing components from production electric vehicles. We also aim to give some general guidelines on how to convert a vehicle to electric drive.
Before you begin:
Please take the time to read.
You undertake your project at your own risk.
The information provided on this wiki and the support forums is intended as information only. The Open Inverter project and contributors to the forums and this wiki take no responsibility for how you use the information on this site, nor any liability for injuries, or death, that may result from your actions.
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Welcome to the open inverter community
Different countries have different legislation, if you want your car to certified for the road in your country please take the time to review this section. It might save you going down the wrong direction and creating something that can never be driven, or incur costs.
The open inverter started as a scratch built inverter and control board led by Johannes Hübner who designed and built his open open source AC motor controller dubbed the "open inverter".
Since then, the community has established and documented hardware and software approaches to reuse OEM inverters with the Open control board, and has more recently started on controlling OEM inverters over CAN, a process which doesn't require replacing any internal parts.
The main goal of the open inverter community is to reverse engineer many of these components for use in a variety of projects such as:
- EV conversion
- Energy storage
- Power generation
- Charging infrastructure
Open inverter projects now span over many different areas surrounding PEV, HEV, and PHEV components, such as:
- Motor Controllers
- 1-3 phase power converters
- DC/DC converters
- buck/boost converters
- Battery Management Systems (BMS)
- Vehicle integration
As a result, there is a growing collection of open source software and hardware designed for the never ending list of OEM parts.
There's a variety of methods of repurposing these OEM components. Methods here are generally chosen with future proofing in mind , reducing chances of firmware or software updates from the manufacture "bricking" or blocking the open source control efforts.
such efforts include:
- Mainboard/brain replacement
- Sync serial
- Sirmware/software reprogramming
Resulting in many bespoke boards running the main open inverter software or other open/semi-open source code designed to ether replace OEM motherboards or VCUs.
This has lead to a large collection of different boards and software, many with redundant features. To unify many of these development projects, the community at large is focused on making a set of standard VCUs and replacement control boards which handle the ever growing list of OEM components.
Many of the VCU and replacement boards consist of these 3 main parts:
|The design and development of the control hardware based around an STM32F103 chip. This provides the control signals to the power stage and on to the attached components.||The development of the code that goes on the STM32F103 chips and determines, amongst other things what signals are sent to the power stage and the attached components.||Using an ESP8266 chip, the development of a simple web based interface to adjust the parameters on the firmware chip and to display values returned from the chip, for example motor speed (RPM).|
Please note: Performing a 'full' EV conversion can often be more straight forward than trying to make small modifications to OEM vehicles - an OEM system will normally require a set of components all talking to each other and keeping each other happy! Trying to, for example, add a different battery charger, or bypassing certain restrictions will often require significant reverse engineering of the existing system to ensure that the new component(s) do not cause errors or problems in the system which can avalanche into significant problems! A full EV conversion, in comparison, can usually focus on just keeping one component happy at a time (although integrating these different components can still require a lot of work).
The Community is focused on the electrical systems required for an EV, and may not be best placed to assist with mechanical issues specific to your vehicle.
Glossary of Terms
It is recommended you read the Glossary of Terms before you begin. Often you'll find TLAs (three letter acronyms) peppered through the support forum and on this wiki, take the time to familiarise yourself with them before hand, remember this exists, or bookmark/favourite it so you can referent back to it.
A few main parts are needed for an EV conversion, such as:
- (Note: ZombieVerter projects require a matched pair of Inverter and Motor as they would have come out of a vehicle)
- Chargers / Charge Controllers
- DC/DC Converters
- HV Junction Box
- Brake Assist
- Vacuum Pumps
- Electronic Brake Boosters
- Power Steering
- Rapid Charging
- VCU Comparison
Existing information on these items can be found on the EV Conversion Parts page.
A variety of OEM parts members of the community have reversed engineered for custom use cases:
- Isabellenhütte Heusler
- Land Rover/Jaguar
- VAG (VW, Audi, Skoda, Seat, Porsche, ...)
To perform a successful EV conversion, you may require the following skills and/or knowledge (this is not an exhaustive list)
- You will need to have the skills, knowledge and tools required to perform significant mechanical work on your vehicle. A service or workshop manual will be useful.
- Basic DC electrical knowledge, such as using a multimeter, soldering, identifying components.
- A willingness and ability to troubleshoot problems (mechanical, electrical, code...).
- Safety in relation to high voltage DC systems. HV DC can be more dangerous than AC mains voltages!
- Basic understanding on the purposes of various EV components (motor, inverter, DC-DC...)
- A grasp of 3 phase motor control concepts can be useful (especially if using an openinverter control board)
- An understanding of CAN (and other digital communication systems) will be very useful
- The legal restrictions and requirements for your country/state
- Common Inverter FAQ - questions common to all hardware variants
- Tesla Inverter FAQ - questions regarding Tesla Large Drive Units and Small Drive Units
- Electronics Basics - general advice for troubleshooting electronic circuits
- cheap EV conversions - this entry point for the penny pinchers
- performant EV conversions - where torque trumps money
Mechanical Design Database
here you will find measurements, models, files, etc for a variety of components such as:
- adapter plates
- motor couplers
- drive shaft flanges
- battery mounts
Open Inverter Projects
Open Inverter (Core Project/s)
|Description / Notes|
|ZombieVerter VCU||Designed around a matched pair of Inverter and Motor taken from the original OEM vehicle the ZombieVerter is there to make those two components believe they are still in the original vehicle and are fed necessary commands to act as if they still are and interpret and responses back from the equipment for feedback (regen / rpm / etc)|
|Open Inverter Hardware||Quite flexible in its application. The Open Inverter can be used to build a custom inverter itself where you supply the high power and high voltage components to create your own inverter, or to be used as the basis to take over control of OEM inverters so that they can drive nearly any attached motor to that inverter.|
|Open Inverter Software||Two of the more important software aspects to master are below.|
Common across boards is the ability to communicate with a CAN Bus, which is a 'control area network' or a technical way of saying how various components, sensors, controls, etc communicate with one another within the car. Read more about CAN Communication
There is also a project to standardise the messages across the various control boards, read more
The openinverter firmware uses a set of about 70 parameters to adapt it to different inverter power stages, motors and position feedback systems. Also it lets you calibrate the throttle pedal, change regenerative braking settings and so on.
Open Inverter Related Projects (Control Boards/VCUs)
|Project||Description / Notes|
|Tesla Small Drive and Large Drive Units:||Commonly there is a large drive unit and small drive unit available from the Model S.
These combine the inverter and motor into a single package.
The control boards for these replace the existing control board within them.
|Lexus GS450h Drivetrain:||The GS450h contains a gearbox (where the motors are located).
Using the ZombieVerter VCU, the inverter and the gearbox itself provide
a powerful set up suitable for rear wheel drive set ups, replacing the existing longitudinally mounted gearbox.
|Prius Generation 3 Inverter:||A cheap available inverter from the popular Prius hybrid, this
board goes inside that inverter and allows you to control the features of it.
|Auris/Yaris Inverter:||Similar to the Prius board, there's subtle differences between them
and therefore the need for a separate board.
|Nissan Leaf Gen2 Board||Replaces the nissan OEM logic board with a rev 3 openiverter main board|
|Ford ranger ev board||openinverter kit for the ford ranger ev|
|All Control Boards / OEM Inverters|
Use inverter as a battery Charger
Both the open inverter and some OEM inverters can be used as a battery charger, further saving on component costs. You can read more about how the open inverter and the theory of charging here.
Open Inverter Renewables Projects
Recently added to the forums are projects and discussions around turning the Open Inverter project towards capturing, storing and using renewable energy.