Support

Hi, I have a brand new, less than 48 hours old v5.5 board which worked for a few good charges, but now won't hold the relay closed for more than about 30 seconds.  It starts humming, then releases and gives a grounding error.  The ground error makes since, as the test is expecting a closed relay.  Disconnected, the relay draws 158mA, which seems to be in spec.  I suspect this is an issue with the Q2 transistor not sinking enough current, and the coil voltage falls off.  Any thoughts?

Thanks,

Chad

Just wanted to chime in-- just like Neon.leon I recently got a 5.5 board to replace the electronics (appears the old wifi module power cable got too close to to contractor and fried all my electronics... my error in cable routing but the new 5.5/wifi is better placed, at least) and I ran into both the relay opening and the incompatible button issue-- I'd second adding a note about the current button connector type.

Fortunately I got a wifi module with my new unit.   Changing to the recommended PWM settings appears to have fixed the issue (or at least its run for a few minutes now with that setting).

Might want to send emails to people getting 5.5 boards to warn them of this. If it weren't the middle of the night when I first had the opportunity to test it I probably would have torn down the unit and checked all the grounding lugs before searching for a support issue. :)

This was a very irritating problem for me as well.  I had two of the units not working correctly.  The problem I had was using the command $Z0 RAPI to make the changes stick.  So thank you for mentioning this.

I feel like this thread needs to be stickied

I have found the same issue.  I ordered a new main board and just received it last week and installed it a few days ago.  It worked briefly but I noticed right away that the unit had produced a weird squeal-hum noise.  When i tapped the box, the relay dropped out and display showed the error "Error No Ground".

On the support site, i just found this article: https://openev.freshdesk.com/support/solutions/articles/6000248647-openevse-closes-relay-may-charge-for-some-time-then-displays-error-no-ground-earth-ground-

This explains the same thing you all described.  I am VERY irritated about this.  I purchased this board to fix my older unit that died, and now I need to add a Wi-Fi module just to change a setting!!!  Why is this "variable relay power" feature enabled by default?   

And another note the connectors are different on this board and not compatible to the older display and button on older stations. And you can't just by the cables needed on the OpenEVSE parts store.  I wish the part store would mention this concerning replacement for older charger stations.

@Support and @Tyler,   Success!   I have tried the value to disable the feature, "$Z0 255 255" and that worked.  I now measure 11.77VDC and 0VAC on the Relay coil.

I have also tried the value "$Z0 200 200"  and that works too.  I measured 9.07VDC and 4.61VAC on the Relay coil.  I figure the value of 200 is almost 80% for coil power which should hold the contacts closed.  I now can tap on the relay and box and the relay no longer looses contact.

Open EVSE Support, thank you for the feedback.  I do suggest adding more details about this feature and explain WHAT this feature is intended for and how to disable it and the exact values to enter.  I'm not a programmer for systems like this and would not expect the data to require spaces.   It would be helpful for others to have examples of values and the percentage Relay coil power it provides, and the expected response from the RAPI command box. 

Thank you again for the support and I hope to continue using my Open EVSE product as long as I can.

Side note, the reason I had to replace my main board and display is due to a lightning strike that blew out the fuses and apparently killed the boards.  I AM ADDING lightning protection to my power inputs to the main board.  I suggest that you add this to your next design.  I'm adding MOVs, and replaceable primary fuses before power feed to the boards.

@Support  Thank you for the reply.  The spaces are required?  I would have thought spaces would be stripped out and not necessary.   I did not try it with spaces, so I will try this now.

Neon.Leon

I share your frustrations.  I've got 5 openEVSE units in my family.  The two newest with this feature are always causing me trouble.  Like you, I've done the suggested commands, but one of my units is very unreliable.

I've been a been fan of openEVSE for a while.  But this problem has left somewhat of a sour taste in my mouth. The charging equipment we use should be dead-on reliable.

Please post here if you come across any helpful solutions or if your new support ticket results in anything.

I am once again disappointed by this feature because the solution DID NOT WORK for me. After purchasing a new WiFi module, waiting for weeks to receive it, and finally installing it, I find solution provided (the command $Z0 RAPI) fails to work. I’m extremely frustrated with this.

The relay still has a high pitch squeal/hum and the voltage reading on the relay coil is low, where I measure 5.7 VAC and 2.96 VDC.

I still don’t understand why this “variable relay power” feature is enabled by default. This can cause the relay contacts to burnout due to loose contact pressure and CAUSE A FIRE!!! I cannot use this EVSE in this condition.

I know the WiFi communication works since I can control the EVSE because I can pause charging, read charging current and other items. Plus when I enter the RAPI command $Z0 , I receive the response “<$OK^20”. By the way, documentation of this never mentions what a user should expect as a response.

First I want to note that I chose to set the “ms to run at 100%” as 200 milliseconds.

I have tried entering the values: $Z0200160, $Z0200194,$Z0200200, and $Z0200255 with no change found in the hum noise or relay coil voltage.

Note I calculated these values as:

160=63%, 194=76%, 200=78%, 255=100% Again I wish documentation would provide more examples of potential values to use.

I’m going to submit another trouble ticket on this and HOPEFULLY get a response.

That worked but I'd be interesting to know what the defaults are and why I had to change it???

Hi,

I found the solution, but the forum is not showing my post until it is "approved."  

Bottom line, go to dev mode, RAPI, and type the following:

$Z0 100 105

The relay pin is using PWM after it closes the relay to reduce the hold voltage.  This is causing the humming, and eventually it lets go.  This command fixed mine in one shot.  

Here's how it works:

Enter the command $Z0 xxx yyy

xxx = the number of ms to run 100% power

yyy = the power out of 255 (example 90/255 = 0.35 or 35% power)

Hope this helps,

Chad