OpenEVSE - Open Source Charging Station

[lincomatic]

In regards to on the fly current resetting, you can always just disconnect power to the car and then reconnect it. I don't think it would be much of a problem.

That doesn't work when you try to charge by overriding timers, which is what I usually do when I'm not at home.

 

[Barbouri]

Is github OK with everyone? They just released a new Windows client to make things easier to use, and it's easy to download the whole repository as a single zip file.

github works for me. Just upgraded to the latest github windows client.

All my Open EVSE boards are socketed 28 pin dip, so I will try out the watchdog timer next week, and update after a few days of use.

Greg C.

 

[DarkStar]

It would be great if cars actually pay attention to the pilot's PWM duty cycle during charging and to adjust their current draw on the fly, but I have a feeling that this isn't very common.

Per the J1772-2011 specification, vehicles are required to adjust their current draw within a set period of time if the PWM duty signal changes. I know the Nissan Leaf has been verified to do this.

Our local EVSE manufacturer, Shorepower, added a current monitor on the EVSE output to automatically power off the output if the vehicle doesn't respond to a PWM duty cycle change, maybe OpenEVSE could do something similar?

 

[lincomatic]

Per the J1772-2011 specification, vehicles are required to adjust their current draw within a set period of time if the PWM duty signal changes. I know the Nissan Leaf has been verified to do this.

The spec requires the car to lower the current draw in response to PWM duty cycle changes, but there's no requirement the the car has to adjust it upwards if the duty cycle changes to offer more current. Therefore, say an EVSE has 2 cars charging, and one of them finishes ... the 2nd car might not increase its current draw in response to a pilot change. Is the Leaf verified to increase current draw in response to PWM duty cycle changes? I think I tested this last year, but forgot what result I got.

 

[coolfilmaker]

Regardless, we should have the ability to network OpenEVSEs together and set a group max current.

 

[chris1howell]

Regardless, we should have the ability to network OpenEVSEs together and set a group max current.

I agree. I have been working on a communications protocol for EVSE to GUI comm... I will add something in so we can play with EVSE to EVSE as well...

Here is a thread I posted a while ago about EVSE grouping and current pooling...
http://www.mynissanleaf.com/viewtopic.php?f=26&t=7254

 

[lincomatic]

OK, I just pushed my development code to https://github.com/lincomatic/open_evse" onclick="window.open(this.href);return false;.
From now on, the github repository will contain the bleeding edge modifications to the code.

Please feel free to fork it and submit pull requests with your changes/additions/bug fixes.

Stable code releases will still be available for download from google code as before.
I will also put them on the github download page: https://github.com/lincomatic/open_evse/downloads" onclick="window.open(this.href);return false;


The code I just checked in is not fully tested, and isn't ready for production use yet.
Changes:
1) 1 button configuration menu for setting max current, service level, enable/disable diode check, etc.
short press cycles through the menu items, long press selects. To use it, you need to hook up an SPST switch between A3 and ground (optionally, add a 10K resistor in series), and make sure #define BTN_MENU isn't commented out.
2) fix for Chevy Volt timer - doesn't seem to be working correctly yet .. needs more work
3) some code cleanup. global lcd object moved into OnboardDisplay class.

I will post in this thread when the code is fully tested and released.

 

[garygid]

I thought that the LEAF did NOT follow the Control Pilot once the charging had started.
Am I wrong, or was that only for 2011 models, or only for the first firmware?

 

[DarkStar]

I thought that the LEAF did NOT follow the Control Pilot once the charging had started.
Am I wrong, or was that only for 2011 models, or only for the first firmware?

The testing that Shorepower has done was on a 2011 Leaf and reflected that it followed the PWM pilot signal both up and down.

 

[Ingineer]

Darkstar is correct, it obeys the pilot. It wouldn't be J1772 compliant if it didn't.

-Phil

 

[GlennD]

I just loaded your beta code to my test unit. Moving through the menus and changing a perimeter works well. How do you save the settings? When I power up the EVSE it comes up as L1, 0 A selected. This would be a disaster trying to resume after a power failure.

 

[lincomatic]

I just loaded your beta code to my test unit. Moving through the menus and changing a perimeter works well. How do you save the settings? When I power up the EVSE it comes up as L1, 0 A selected. This would be a disaster trying to resume after a power failure.

Hmm. It was working before. I guess some of the recent changes I made broke it.
Thanks for giving me the heads up.
I have a different issue, which is that whatever current I set is completely ignored after a reset.

All of the settings done through the menu are supposed to be saved to EEPROM, so they are supposed to survive a reset/reboot.

I'll post here once I get it fixed.

 

[lincomatic]

Glenn,
I just pushed a fix for the bug in handling saved settings to github

 

[GlennD]

I just tried your latest and it works fine. It saves the settings and the scope shows that the current tracks.

 

[RickS]

Some pictures of the box I built in a Pelican Case. With cable glands this should have equivalent NEMA 4X water tightness. Got a hold of a REMA cable, which interestingly enough uses aluminum cable.

http://i135.photobucket.com/albums/q122/ricksuiter/Open%20EVSE/2012-06-09_22-02-32_281.jpg" onclick="window.open(this.href);return false;

Padlocked to the front wheel

http://i135.photobucket.com/albums/q122/ricksuiter/Open%20EVSE/2012-06-09_22-22-19_3.jpg" onclick="window.open(this.href);return false;

http://i135.photobucket.com/albums/q122/ricksuiter/Open%20EVSE/2012-06-09_22-21-57_295.jpg" onclick="window.open(this.href);return false;

Up close of everything coiled up with a cable cuff to the handle of the Pelican Case.

http://i135.photobucket.com/albums/q122/ricksuiter/Open%20EVSE/2012-06-09_22-24-41_421.jpg" onclick="window.open(this.href);return false;

 

[Ingineer]

Some pictures of the box I built in a Pelican Case. With cable glands this should have equivalent NEMA 4X water tightness. Got a hold of a REMA cable, which interestingly enough uses aluminum cable.

Great job on your EVSE, But I seriously doubt anyone would manufacture any type of temporary/flexible cable with Aluminum. The metallurgy is simply not up to the task.

Maybe you saw the tinned copper conductors and made an incorrect assumption. AL cable is really only used for transmission/distribution anymore, and they are all clearly marked on their jackets when insulated.

-Phil

 

[QueenBee]

AL cable is really only used for transmission/distribution anymore

Let's leave it at that

 

[Ingineer]

AL cable is really only used for transmission/distribution anymore

Obviously a completely different context than your comments but I learned the hard way that literally almost every low voltage cable relating to computers except for CAT5 is aluminium. (Had a few barrels full of misc. old cables and was hoping for 75 cents a lb but once I started sorting through it and looking at the wires I discovered that literally everything was AL.)

I'm sure you are in error. You can't solder to Aluminum, so it is rarely used in low voltage applications. There would also a big galvanic potential issue, and terrible reliability.

I can't tell you how many people look at tinned copper and assume because it's silver colored it must be aluminum. WRONG!

Go to any electronics supplier, such as Mouser, Digikey, etc. Try to even FIND wire like that. Simply not available! That should be all the proof you need!

The only exception I can think of is Co-ax cable. They routinely use aluminum for this application, especially on the shielding.

-Phil

 

[QueenBee]

AL cable is really only used for transmission/distribution anymore

Obviously a completely different context than your comments but I learned the hard way that literally almost every low voltage cable relating to computers except for CAT5 is aluminium. (Had a few barrels full of misc. old cables and was hoping for 75 cents a lb but once I started sorting through it and looking at the wires I discovered that literally everything was AL.)

I'm sure you are in error. You can't solder to Aluminum, so it is rarely used in low voltage applications. There would also a big galvanic potential issue, and terrible reliability.

I can't tell you how many people look at tinned copper and assume because it's silver colored it must be aluminum. WRONG!

Go to any electronics supplier, such as Mouser, Digikey, etc. Try to even FIND wire like that. Simply not available! That should be all the proof you need!

The only exception I can think of is Co-ax cable. They routinely use aluminum for this application, especially on the shielding.

-Phil

Wow, this makes so much more sense. Count me in that group!! The funny thing is when I was sorting through it I would cut the wires and sometimes see shimmers of copper and then strip the wire to just see silver. But now after more experimenting I see that scraping the tin layer off reveals copper. I'm surprised that the metal recycling guy didn't catch this.

TIL that most (all?) the wires that I thought were made of aluminum are actually tinned copper. Looks like a lot of the foils and maybe shielding might be aluminium still.

Thanks for teaching me new things Phil!!

 

[RickS]

I'll look at it closer and maybe scrape away at some of the ground wire. The cable itself feels a bit on the light side for it's size.