Tag Archives: SAE

May 13 2012
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computer, electric vehicle, electrical, energy, engineering, interview, mechanical, Uncategorized, vehicle

Open-EVSE, an OSH Charging System for Electric Vehicles

Everyone should start keeping track of what Google is doing (if they weren’t already).

Just a few days ago Openalia posted about Google’s open source simulation software for planning heliostat arrays. Today it’s about the hardware and software for an Arduino shield that charges any electric vehicle (EV) off of household current.

The Open-EVSE (electric vehicle supply equipment) is for charging J1772 compliant EVs. SAE J1772 is a specific type of connector.

So, basically, EVs get parked in the garage and plugged into a special computer to recharge their batteries. It’s important that the wall power be carefully metered out to maximize the life of the expensive battery pack. This thing does that, but it costs way less than its commercial equivalents and it’s open source.

Today we will be interviewing Chris Howell, the driving force behind OpenEVSE.

Okay, Chris, what is your background?

  • I am a Network Engineer and have way too many hobbies… Pilot, Electronics, Ham Radio, RC planes/UAVs…

Did you have any engineering experience before you started?

  • I build networks for a living. I did not have any experience in building complex electronic circuits or programing before I started.

When did you start and when did you decide to go open source?

What made you decide to open source the project?

  • The decision to Open Source “OpenEVSE” was made because the Electric Vehicle industry desperately needed an inexpensive Charging station/ Electric Vehicle Supply Equipment (EVSE). The existing hardware is far to expensive ($750+) and the manufactures are taking advantage of consumers with outrageous labor costs to install the charging station.
  • My quote to install the charging station form Nissan’s partner AV was over $1200. I already had a breaker in the panel and the charging station was to be located 18 inches away.

Did you choose one particular license over others? Why?

  • Not really… The licences are pretty confusing, we just picked a common license.

Were there any tools/resources that were vital to your success?

  • The Arduino paved the way for OpenEVSE. I bought an Arduino and out of frustration with my ridiculously high Charging Station quote I decided to see if I could use it to generate a J1772 pilot signal. J1772 is the standard in use by the EV industry. It is a 1khz square wave generated by the Charging Station. The voltage drop determined the EV state and duty cycle tells the EV how much current it can draw.
  • After a couple hours with the Arduino I was able to implement the pilot.
  • Other resources that were very helpful were the tutorials from Adafruit and Sparkfun. I had to learn a lot about SMD stenciling, microprocessors and opamps.
  • DorkBotPDX is great for the many prototype boards and OHARARP for the SMD stencils.

Any tools that were just really cool that everyone should know about?

  • I really like the DSO Quad scope. It has been really useful for this project.
  • The electric skillet for solder reflow is awesome.

Could you suggest one really important skill people should learn first?

  • Learn how to program an Arduino.
  • Once you know what a microprocessor can do lots of ideas start flowing.

Were there any significant changes between revisions or forks?

  • No significant changes just a slow progression of improvements and added features.

How much of the project was individual effort and how much was social?

  • The hardware was mostly individual with a few suggestions from really smart people. I brought the project to the stage that I was able to successfully charge my Nissan LEAF. Shortly after I recieved an email from “lincomatic” another LEAF owner who offered to make improvements to the software.
  • Now I still do most of the hardware, but both lincomatic and I add to the software. OpenEVSE is starting to see some small contributions from the community. Hopefully more people will contribute to the project over time.

Are you anywhere close to feeling “done” with the project?

  • The project is not done but it is mature. Open EVSE fully supports J1772 and all the same safety features as the “big boys”… GFCI, ground monitoring, stuck relay detection.
  • There are a lot that can still be added touch screen LCD, Internet connectivity, energy metering, etc.

Do you plan on selling anything when you’re finished?

Has it been successfully used in a real job? By anyone else?

  • Yes, OpenEVSE is in use by owners of the Nissan LEAF, Chevy VOLT, Toyoda PiP and Mitsubishi i-MiEV. Tesla and BMW Active-E owners are currently building Charging Stations. To date over 50 OpenEVSE boards have shipped.

Where do you want to take the project from here?

  • I would like to interface OpenEVSE with a Raspberry Pi to provide a rich web interface and also a graphical interface.

What do you think about open source as a philosophy? As a strategy?

  • Open Source is a great way to get people interested in a project and to spark innovation.

Do you follow any other open source projects?

  • Arduino and Raspberry pi.

In your wildest dreams, what would be open sourced next?

  • Everything…
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