Test C - EVSE Error no ground

[Christian Hobbs]

I'm on the final step of testing an OpenEVSE built (mostly) at the Norcal workshop last weekend.  

The unit passes all the tests except for test C.  The LCD briefly displays a blue screen and says charging, then switches to a red screen and says EVSE Error no ground. 

It is plugged into two phases of a 3 phase 240. The outlet is properly grounded. Although I haven't checked the ground resistance yet, there is a copper ground wire that runs all the way back to the panel, I'm not relying on the conduit. 

This outlet was previously servicing a Clipper Creek LCS-25 without that unit reporting any errors.

Any suggestions for troubleshooting?

[Christian Hobbs]

This photo was taken before the second set of relay test leads were installed.  

[chris1howell .]

From the photo it looks like the relay is plugged into the lower 2 position of the relay block (Relay 2). For a single relay the relay should be plugged into the upper (closest to ground) and the middle. In the next version of code (2.0B2) it will not matter as both ports are activated.

On Thu, May 23, 2013 at 7:05 PM, Christian Hobbs <christia...@gmail.com> wrote:

This photo was taken before the second set of relay test leads were installed.  

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[Christian Hobbs]

Hi Chris,

I'm sorry, I don't understand your reply. Here's a better photo, showing my completed wiring. As far as I can see, my wiring is functionally identical to the example in the assembly docs posted by Ron Hansen, several other photos on the google code site, and photos of other projects I took at the workshop. The only difference between this and the Hanson example is that I'm connecting one of the relay pairs to the fuse block side of the wire instead of the relay side. 

My project:

Ron Hansen's photo:

The back of the relay is numbered, here are my connections:

Relay 4 - AC Test 1

Relay 8 - AC Test 2

Relay 2 - AC Line 1

Relay 6 - AC Line 2

[Javier Henderson]

I believe Chris was referring to the cables going to the relay coil, which are not clearly visible in the new photo you attached.

-jav

[chris1howell .]

Yes, Jav is correct. I was referring to the connections going to the right side of the Openevse board.

From top to bottom you should have pilot (orange) - ground - relay coil - relay coil - not connected.

From the first photo it looks like your connections are. Pilot - ground - not connected - relay coil - relay coil which would be incorrect.

[Christian Hobbs]

Thanks Jav and Chris!  That was an easy fix. It works perfectly now with the tester and in production. 

I did not realize that OpenEVSE could support a second relay. That's fantastic, I was actually thinking about building a two-headed EVSE at some point, so that two cars could be plugged in overnight and charge serially.  Is this the use case you had in mind Chris or are you intending parallel charging support (or both?). 

This was a really fun project, and much easier than I imagined. The system quality, especially using the Diversified Stage enclosure, is impressive. I'll definitely add WiFi and power monitoring to this unit when I have time. 

Kudos to Chris, Sam and all the contributors. OpenEVSE is a fantastic value. 

[Nicholas Sayer]

I believe the intent of the two separate relays is for each of the two hot lines to be controlled by a separate SPST relay rather than for both to be controlled by a single DPST relay. Using two relays allows for separate stuck-relay tests on each hot line.