chris1howell
Posts: 649
Joined: Tue Aug 10, 2010 1:40 pm
Delivery Date: 15 Jun 2011
Leaf Number: 4122
Location: Lancaster, Ca

Weekend(s) Project - DIY EVSE

Tue Feb 15, 2011 9:58 am

This weekend I decided to see if I could build a control pilot based on the J1772 Spec. I am really frustrated with the current lack of good options. I received an outrageous quote from AV like most others here and I am not about to buy from them and have it installed.

My perfect EVSE would be:
Simple
Small (portable)
Inexpensive
It does not need any features other than those to keep it safe and make it work well. The cars can implement all the cool stuff.

So... I pulled together some parts I had on hand. An Atmel 328 Microcontroller an LCD screen some switches, resistors and a few other basic components.

I was able to generate the 1khz pilot signal and use a couple of switches to select higher/lower current settings by telling the micro controller to adjust the duty cycle of the pilot.

The Micro controller properly detects all the J1772 EV states by “Not Connected" 12V, "EV Connected" 9V, "EV Ready - Charging" 6V - "EV Ready - Ventilation required" 3V and pilot "Error" 0V.

I have not implemented the Negative 12V safety check and GFI detection because I did not have the required parts on hand.

I have posted a pretty bad video on youtube here: http://www.youtube.com/watch?feature=pl ... MfpxmG4zNE
Sorry for the quality, I was late for work but I wanted to get it posted.
Last edited by chris1howell on Wed Aug 10, 2011 10:03 am, edited 1 time in total.
2011 LEAF: Red SL #04122
2012 Tesla Model S #01530
EVSE: OpenEVSE, 40A L1/L2 -- http://www.openevse.com
PV System: 28 x 210W -> 5.8 kW DC

OpenEVSE Store: http://store.openevse.com

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garygid
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Re: Weekend Project - J1772 Control Pilot

Tue Feb 15, 2011 10:35 am

Good work, Thanks.
No audio with your video?

The little board was your EV-simulator?

What's your next step?
PM if you want any help.

If you put in one external "Reset" input button, then you can control the Max-Current with that. In firmware, detect Reset held for 5 seconds to go into Parm-Set mode. Then, short press to cycle through parms, if there are more than one. For the Max-Current, start low, at perhaps 8 amps, then 12, 16, 24, and 32 amps. Possibly also 10, 15, 20, 30, 40 for 1-hour charging (not a continuous load)?

In any case, nice work.

I found a 40-amp 240v rated relay used for turning A/C systems On/Off. The L1 EVSE appears to use two single-pole relays.

Also, a "Universal" voltage input AC to 12v regulated DC power supply, where one might add some components to make the 5v and -12v? I have not looked extensively for a dual-output unit.

Perhaps add a small relay to switch the power relay, as the L1 EVSE appears to do?

Or, we could take apart an L1 EVSE and actually tell folks what we find, if EVD... does not want to share what they found in the L1 EVSE?
See SOC/GID-Meter and CAN-Do Info
2011 LEAF, sold in 2015
2010 Prius, 2014 silver Tesla S
Nissan EVSE, mod to 240/120v 16A
PU: SDG&E
Solar PV: 33 x 225W -> 7 kW max AC
To Sell: X-treme 5000Li EV motorcycle

chris1howell
Posts: 649
Joined: Tue Aug 10, 2010 1:40 pm
Delivery Date: 15 Jun 2011
Leaf Number: 4122
Location: Lancaster, Ca

Re: Weekend Project - J1772 Control Pilot

Tue Feb 15, 2011 11:24 am

Thank you Gary.
Sorry No Audio, I was in a hurry this morning. I will make another video soon. I want to also show a striped down version with no LCD, just LED status indicators and current set by jumpers.

You are correct the little board is my EV simulator.
Both switches off is 2740 Ohms bringing the Pilot from 12V to 9V indicating EV connected.
Switch 1 on brings resistance to 886 Ohms pulling the Pilot to 9V indicating the EV is ready accept to charge
Switch 2 on sets resistance to 246 Ohms and a voltage of 3V indicating Ventilation Required.

I like the 1 button idea. Simple is better, I will make the changes.
I have been looking at components to make this project a full EVSE. My next step is to add the Universal power supply to power the Microcontroller\Pilot\Relay and add the higher power relay control (there is currently an LED in its place). I plan to use a transistor to drive the coil, the ATMEL chip only puts out 40ma. For DC Power I will just use a single output transformer with two regulators to get both 12VDC and 5VDC.
2011 LEAF: Red SL #04122
2012 Tesla Model S #01530
EVSE: OpenEVSE, 40A L1/L2 -- http://www.openevse.com
PV System: 28 x 210W -> 5.8 kW DC

OpenEVSE Store: http://store.openevse.com

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garygid
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Re: Weekend Project - J1772 Control Pilot

Tue Feb 15, 2011 11:34 am

With a transformer, you will be making a L2 (or an L1), but not an L1/L2 version, right?

What is generating (will generate) the -12v, nothing yet, right?

Where are you located?
See SOC/GID-Meter and CAN-Do Info
2011 LEAF, sold in 2015
2010 Prius, 2014 silver Tesla S
Nissan EVSE, mod to 240/120v 16A
PU: SDG&E
Solar PV: 33 x 225W -> 7 kW max AC
To Sell: X-treme 5000Li EV motorcycle

DarkStar
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Joined: Sat Jul 17, 2010 10:06 am
Delivery Date: 25 Mar 2011
Leaf Number: 568
Location: Hillsboro, Oregon, USA
Contact: Website

Re: Weekend Project - J1772 Control Pilot

Tue Feb 15, 2011 11:44 am

Looks awesome! You should chat with David at Modular EV Power as he is currently working on a full EVSE control board.

Any chance we could see some schematics or source code? I don't know much about AVR programming, except I've played around with an Arduino a bunch (it's a special AVR bootloader), but I can't seem to figure out how to output the proper PWM signal from it... Thanks! :D
Mikiko (2011 Nissan LEAF ETEC) Status:
Reserved: 04/20/10 | Ordered: 10/01/10 | EV Project Blink Installed: 03/22/11 | Delivered: 03/25/11 | VIN: 568

Oregon Electric Vehicle Association | Electric Auto Association

chris1howell
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Joined: Tue Aug 10, 2010 1:40 pm
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Location: Lancaster, Ca

Re: Weekend Project - J1772 Control Pilot

Tue Feb 15, 2011 12:00 pm

DarkStar: I am willing to share the schematics and source code with select members of this community, I am not ready to make them public. I really do not want to encourage everyone to play with high AC voltages and build their own EVSE's.

What version of the Arduino are you using? The Audrino bootloader has 3 default timers whigh set the PWM Frequency. The newer Arduino's running at 16.000Mhz are running Digital pins 5 and 6 at 16 MHz / 64 / 256 = 976.5625Hz. The information is a bit hard to find but searching for "Arduino PWM" will get you headed in the right direction.
Last edited by chris1howell on Fri May 06, 2011 9:11 am, edited 1 time in total.
2011 LEAF: Red SL #04122
2012 Tesla Model S #01530
EVSE: OpenEVSE, 40A L1/L2 -- http://www.openevse.com
PV System: 28 x 210W -> 5.8 kW DC

OpenEVSE Store: http://store.openevse.com

DarkStar
Posts: 2066
Joined: Sat Jul 17, 2010 10:06 am
Delivery Date: 25 Mar 2011
Leaf Number: 568
Location: Hillsboro, Oregon, USA
Contact: Website

Re: Weekend Project - J1772 Control Pilot

Tue Feb 15, 2011 12:45 pm

chris1howell wrote:What version of the Arduino are you using? The Audrino bootloader has 3 default timers whigh set the PWM Frequency. The newer Arduino's running at 16.000Mhz are running Digital pins 5 and 6 at 16 MHz / 64 / 256 = 976.5625Hz which is well within the J1772 Spec. The information is a bit hard to find but searching for "Arduino PWM" will get you headed in the right direction.

Hmm, I I thought the J1772 minimum specification was 980Hz... I've been rockin' the 16MHz Arduino Pro 168 from SparkFun, so maybe I just need to just start trying some things out!
Mikiko (2011 Nissan LEAF ETEC) Status:
Reserved: 04/20/10 | Ordered: 10/01/10 | EV Project Blink Installed: 03/22/11 | Delivered: 03/25/11 | VIN: 568

Oregon Electric Vehicle Association | Electric Auto Association

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garygid
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Re: Weekend Project - J1772 Control Pilot

Tue Feb 15, 2011 1:02 pm

Can one set the "256" divider to a slightly lower count?
For best compatibility with cars, a 250 count divider would be a lot closer to 1000 Hz.

GFI:
Sense net current with a current-sensor core/coil. Net current of around + or - 20 ma (maybe 10 to 30 for testing) is probably good.

Display kWh total for the charging session:
Use some (5 or 6?) LEDs to show a count of whole (or half) kWh in binary?

Display Suggestion:
Keep the display port and firmware support for testing and debugging.
See SOC/GID-Meter and CAN-Do Info
2011 LEAF, sold in 2015
2010 Prius, 2014 silver Tesla S
Nissan EVSE, mod to 240/120v 16A
PU: SDG&E
Solar PV: 33 x 225W -> 7 kW max AC
To Sell: X-treme 5000Li EV motorcycle

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EVDRIVER
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Re: Weekend Project - J1772 Control Pilot

Tue Feb 15, 2011 1:17 pm

Gary, make sure that when all that is complete it is UL approved or at least the power circuits are tested to comply to their standards before anyone uses it or builds one for home use. I know you would NEVER use such a device at your home unless it has been tested as such:) After many hours of designing, building, adding cords, enclosure and making it all built to be durable I'm sure it will be very affordable. Not to say it is not a fun experience to do and learn but in the end it will never match a factory EVSE, even a modified unless one spends considerable dollars making it comply to all design standards. If you are so concerned over UL why bother other than to tinker? Since I know how one works I have no reason to build my own although some hobby types may enjoy doing so.

I think if you are going to discuss UL on all the other EVSE products on the forum you may want to discuss them on home-made EVSE projects:)

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garygid
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Re: Weekend Project - J1772 Control Pilot

Tue Feb 15, 2011 1:29 pm

1. Learn and Tinker

2. Perhaps replace the Control Pilot generation function of the micro-processor in the L1/L2 EVSE (already non-UL) of yours?

3. No, not build an entire EVSE, but I support learning.
See SOC/GID-Meter and CAN-Do Info
2011 LEAF, sold in 2015
2010 Prius, 2014 silver Tesla S
Nissan EVSE, mod to 240/120v 16A
PU: SDG&E
Solar PV: 33 x 225W -> 7 kW max AC
To Sell: X-treme 5000Li EV motorcycle

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