The right way to stop charging?

[Zdenko Meglic]

Hi. I am writing my own software for the charger but have a problem with stopping the charge.

Can anyone tell me what is the correct way to temporary stop the charging? If I just disconnect the relay, the car (Renault ZOE) is happy, but I dont think that is the right way to do it.

So I stop the PILOT signal in a HIGH level, but then the car reports "charger ERROR", so that can't be good.

Can anyone tell me what the correct way(sequence) to do it is?

Thank you very much!!!

[Sam C. Lin]

The way that the OpenEVSE firmware pauses charging is to simply turn off the PWM .. pilot set to +12V.

I haven’t gotten any reports of any vehicles having trouble with this.

Would you try the stock firmware and see if your ZOE has a problem with it?

[Lee Howard]

Last time I tested turning off PWM during State C while charging a Chevy Volt the OnStar service sent "charging interrupted" text messages to the configured cell phone.  I can't remember for-sure, but I think that there was a similar message on the in-car console as well.  The Chevy Volt will also sometimes give a "check engine" message in such situations that takes a subsequent full charge cycle to clear.

In the event that the EVSE needs to independently stop the charging - I don't think that there is a way you can prevent with certainty that no car will ever complain about that.

As for just disconnecting the relay... that's probably not good except in extreme conditions because you're opening contacts under load which will result in arcing and wear on them.

Thanks,

Lee.

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[Zdenko Meglic]

Hi. Thank you for you answer! Good to hear I'm not the only one who encountered such a behaviour. I will do some more testing, and post the results.

[Zdenko Meglic]

I will try it and report back.

[Zdenko Meglic]

OK, I did some more tests, and the car does stop charging when the pilot goes HIGH. That is good news. 

The error I received was from the pilot being less than 6A, and that is OK, but not related to stopping the charge.

The problem that remains is, once the car stops the charge it will go to sleep and will not continue the charge once the pilot returns...

Any ideas?

On Tuesday, April 10, 2018 at 11:35:04 PM UTC+2, lincomatic wrote:

[Sébastien Maccagnoni]

2018-04-12 9:35 GMT+02:00 Zdenko Meglic <z.me...@gmail.com>:

The problem that remains is, once the car stops the charge it will go to sleep and will not continue the charge once the pilot returns...

​I'm sorry I can't be specific, but I experienced something similar when I had a ZOE, a few years ago.

After doing some tests, I realized that the code to pause the charge made indeed the car go into sleep mode and it didn't wake up.

... and I found out that, if I reinitialized the charge (complete stop and complete start), the ZOE wakes up.

But I don't remember which where the code I sent to the OpenEVSE RAPI...

--

Sébastien
https://www.maccagnoni.eu/

[Zdenko Meglic]

Thank you for you comment. Good to know at least there is a solution! Looks like I will have to do some more tests. 

I wonder what a "complete stop and start" could do. Maybe pull  the pilot LOW, and than high...

Thank you!

[Sébastien Maccagnoni]

After reading the list of RAPI commands again, I think it may be related to:

- "$FS" for sleeping, and which didn't work

- "$FD" and "$FE" (disable and enable), which worked (or maybe even "$FR" (reset) instead of "$FE"...)

But I'm not 100% sure these are the commands I used.

By looking at the OpenEVSE source code, you should be able to see the difference...

2018-04-12 10:10 GMT+02:00 Zdenko Meglic <z.me...@gmail.com>:

Thank you for you comment. Good to know at least there is a solution! Looks like I will have to do some more tests. 

I wonder what a "complete stop and start" could do. Maybe pull  the pilot LOW, and than high...

--

Sébastien
https://www.maccagnoni.eu/

[Zdenko Meglic]

Thank you everyone for your help.

The final solution is to pull the PILOT HIGH, and disconnect the relay within a second. Anything longer and the car (ZOE) will report a charger error!

This seems strange to me, but that's the way Renault implemented it.

[Sam C. Lin]

Hmm. Interesting. I was afraid of arcing the contacts if I just immediately open the relay.

What I do in the OpenEVSE code is I set the pilot to +12V, then wait for the EVSE to respond by going back to STATE B, indicating that the car has stopped charging, before opening the relay.

If it doesn’t do it within 3sec, then I just open the relay.

 

Code snippet:

 

    if (chargingIsOn()) {

      // wait for pilot voltage to go > STATE C. This will happen if

      // a) EV reacts and goes back to state B (opens its contacts)

      // b) user pulls out the charge connector

      // if it doesn't happen within 3 sec, we'll just open our relay anyway

      // c) no current draw means EV opened its contacts even if it stays in STATE C

      //    allow 3A slop for ammeter inaccuracy

      if ((phigh >= m_ThreshData.m_ThreshBC)

#ifdef AMMETER

                 || (m_AmmeterReading <= 3000)

#endif // AMMETER

                 || ((curms - m_ChargeOffTimeMS) >= 3000)) {

               chargingOff();

#ifdef FT_SLEEP_DELAY

               sprintf(g_sTmp,"SLEEP OPEN %d",(int)phigh);

               g_OBD.LcdMsg(g_sTmp,(phigh >= m_ThreshData.m_ThreshBC) ? "THRESH" : "TIMEOUT");

               wdt_delay(2000);

#endif

      }

    }

 

 

From: open...@googlegroups.com <open...@googlegroups.com> On Behalf Of Zdenko Meglic
Sent: Tuesday, April 17, 2018 11:54 PM
To: OpenEVSE <open...@googlegroups.com>

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[Lee Howard]

On 04/18/2018 06:20 PM, Sam C. Lin wrote:

What I do in the OpenEVSE code is I set the pilot to +12V, then wait for the EVSE to respond by going back to STATE B, indicating that the car has stopped charging, before opening the relay.

If it doesn’t do it within 3sec, then I just open the relay.

That is the approach that I've found to work best.  However, Chevy Volts will still send a notice via OnStar to the registered mobile phone of a charging interruption and will also sometimes put the "check engine" light on with a charging error code (which goes away after a subsequent successful charge cycle).

I don't think that there is a guaranteed way on the EVSE to stop the charging without flagging some kind of notice on some EV models.  There's no way for the EV to realize that the ended charge cycle was deliberate on the part of the owner (like is concluded when the proximity switch is closed - which also tells the EV to cease charging) and not a malfunction of the EVSE or the EVSE detecting a fault in the EV charging system (like a failed diode).

Thanks,

Lee.

[gnuarm.del...@gmail.com]

I can't say anything about the J1772 standard does it, but I currently charge my Tesla through a 120 V wifi controlled switch to start and stop charging.  I realize that is not the best way to handle this, but it is presently the only way.  lol 

I see no errors reported by the car, it simply stops charging when power is cut.  There is a mobile connector in the path that does the same sort of "control" as the OpenEVSE device.  The car also starts charging again when power is restored.  In other words, it works just as you might like.

I do realize that this is putting wear on the contacts of the wifi switch.  This is not particularly important to me because it is a very inexpensive device, about $15.  Ideally there would be a way to control charging through an app controlling the car.  I think there may be some third party apps, but I'm not willing to give them the keys to my car.  lol  I'll wait for Tesla to come up with this... or I get a high current outlet to charge from so I don't need to worry about timing the charge end. 

Is there a way to tell the car to stop charging?

  Rick C.

  - Get 6 months of free Supercharging  
  - Tesla referral code - https://ts.la/richard11209

[Nuno Leitao]

With OpenEvse you can charge for x hours, from x to y time or x kw...

Other way might be, cannibalize the pilot wire and interrupt it with a relay, controlled by your wifi plug?

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[gnuarm.del...@gmail.com]

Can you tell me exactly how to send these commands.  Is there presently an app?  Or does it require me to write software on a phone or PC?

  Rick C.

  + Get 6 months of free Supercharging  
  + Tesla referral code - https://ts.la/richard11209

[Marcin Chojnowski]

Openevse has control over serial api. You can do it yourself or use ready solutions based on esp with wifi. 

[Nuno Leitao]

With the wifi module, you access the integrated web page from computer or phone browser and select the option.

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Nuno Leitão

[Nuno Leitao]

have a look on my interface in this moment, will this list support attachments?

if not check the link below

https://photos.app.goo.gl/NKwtrV4Rto2V89j1A

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Nuno Leitão

[gnuarm.del...@gmail.com]

So the device is a web host?  I suppose security is up to the operator to not put this device on a net that is accessible?  I haven't looked into the wi-fi interface at all. 

Thanks for the image.

  Rick C.

  -- Get 6 months of free supercharging
  -- Tesla referral code - https://ts.la/richard11209

[Marcin Chojnowski]

You connect diferrent device that talks to evse via serial. If you want you can expose it publicly but it's better idea to VPN in and then use the web UI. 

[Nuno Leitao]

yes, the wifi module allows you to do many stuff there.

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Nuno Leitão