OpenEVSE Plus v3 and Current Measurement

[bpm...@gmail.com]

Where does the current measurement CT plug in if you're building the v3 board? Is it the A_CT jumper? Is there polarity involved or will either way work fine?

Thanks

-Brian

[Craig Kirkpatrick]

I'm surprised this question went unanswered. First you can find the build instructions linked from the OpenEVSE store and the answer is there. Yes, connect the CT to the A CT two pin header and since it is an AC transformer the polarity does not matter. Run one of the hot lines from the AC input through the CT not both (like you do on the GFCI CT). Actually the instructions say to put the CT upstream of the GFCI CT but honestly space is pretty crowded in that spot compared to the input side. Maybe you'll measure a little idle current when the car is not plugged in but who cares about something like 0.1 AMP. Let me know if this does not make sense since nobody is born knowing how to do this and acronyms don't help everyone.

[bpm...@gmail.com]

Chris answered me when I emailed him directly. I built the kit before the build instructions had been updated for the new current measurement option. Heck, I even ordered my own CT from Digikey because he didn't have them in stock yet. Everything works like a champ. Couldn't be happier.

[Craig Kirkpatrick]

Chris runs a class act.  Now I get why nobody appeared to reply to your query.  Chris is a gentleman who understands customer service so well I'd hire him myself if he wasn't super happy in his current situation. 

I'm happy you are taken care of. Happy EV miles ahead for you. 

Best Wishes,

Craig 

On Oct 16, 2014, at 6:42 PM, bpm...@gmail.com wrote:

Chris answered me when I emailed him directly. I built the kit before the build instructions had been updated for the new current measurement option. Heck, I even ordered my own CT from Digikey because he didn't have them in stock yet. Everything works like a champ. Couldn't be happier.

--
You received this message because you are subscribed to a topic in the Google Groups "OpenEVSE" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/openevse/K_iqvvT1t48/unsubscribe.
To unsubscribe from this group and all its topics, send an email to openevse+u...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[chris1howell .]

Thanks guys... OpenEVSE has been a very fun and rewarding project for me. I really enjoy meeting so many like minded people with a desire to build and understand how things work. It is my pleasure to be a part of this growing EV community.

Chris

[Mark Moorcroft]

Now that I finally have my car back with the battery pack replaced, and the electrician installed the outlet, I have been able to start trying out my 50A OpenEVSE. I'm wondering if the current reading is normally so poorly "buffered" that it's impossible to read, or this is a function of my Fiat pulling wildly varying current. I can tell that it varies from under 10 amps to over because the second digit goes on and off. But aside from that it's impossible to tell what the current draw is. I also wonder if there is any calibration needed in the firmware or if you just get what you get. Is there room in the firmware to slow down the response so the reading can handle these apparently wild swings? I installed my transformer as suggested in this thread on the input side to keep it away from interference and because there is more space. I can check the current with my meter but to be honest I'm less concerned about accuracy than I am about getting it so I can read it all. And the meter won't help me with that. I have a few other comments and questions too that I am posting in a new thread.

[Craig Kirkpatrick]

I could post a firmware file that I use from firmware modifications I made in order to have a running 32 averages so the reading is more like you and I expect. It works nicely.  I coded calibration coefficients also in mine so I get perfect measurement correlation to a panel meter I put in my home circuit breaker box. You'll need the programmer Chris sells in order to download the firmware. The cable powers the board so you can shut off the 240V breaker and work on this safely.  I'll post it later today or tomorrow. 

Best Wishes,

Craig

--

[Craig Kirkpatrick]

Ok. Here is the firmware with the measurement averaging. Test it and tell me if you like it or if you see anything needing some attention.

https://dl.dropboxusercontent.com/u/54693684/OpenEVSE/open_evse.cpp.hex
https://dl.dropboxusercontent.com/u/54693684/OpenEVSE/openevse_Craig.bat
https://dl.dropboxusercontent.com/u/54693684/OpenEVSE/eeprom.bin

Best Wishes,
Craig

[lincomatic]

Please post the source code so I can merge your changes into the official firmwares.
Thanks.

--
You received this message because you are subscribed to the Google Groups "OpenEVSE" group.
To unsubscribe from this group and stop receiving emails from it, send an email to openevse+u...@googlegroups.com.

[Craig Kirkpatrick]

https://dl.dropboxusercontent.com/u/54693684/OpenEVSE/Source%20Code/open_evse.h
https://dl.dropboxusercontent.com/u/54693684/OpenEVSE/Source%20Code/open_evse.ino

Best Wishes,
Craig

[Craig Kirkpatrick]

I should have mentioned that I did not touch the Rapi stuff. And browsing the stuff I did touch you'll find reasonable comments.
Best wishes,
Craig

[chris1howell .]

Thank you, Craig for contributing to the OpenEVSE Source code...

Best wishes,
Craig

[James Klafehn]

Is love to add that eBay meter to my next portable, dual voltage EVSE. 

I am not a code guy so I won't be able to modify any hex files myself if that's needed. I'm more of a "follow instructions kind of builder". 

Will this work with any v2 or v3 board? How does it get connected?

Thanks!

--

Jim Klafehn
Three Hills Properties LLC
Emma's Acres LLC
Ithaca, New York 14850
607-229-0082
www.threehillsproperties.com
www.emmasacresllc.com

[Craig Kirkpatrick]

The OpenEVSE V3 board adds a 2-pin connector for the amperage sensing CT connection. You need to get the correct CT coil or the voltage produced across the V3 sense resistor could be way to high for the microcontroller. The OpenEVSE store has everything you'll need.

To blast a hex file into the V3 (or even the V2) you will want to get the OpenEVSE programmer from the OpenEVSE store. Yes it could be done with another tool but the one from the OpenEVSE is a turn-key tool that makes your life simple. I posted my hex file with the improved current reading. With a V3 board and the programmer cable it should be child's-play to update the V3 board firmware and if for some reason you want to fall back to the shipping revision of firmware then find that hex file also on the OpenEVSE store and blast it into the V3 board with the programmer.

For safety' sake I turn off the 240V to my OpenEVSE before I connect the programmer cable to the V3. The programmer will power the V3 since the other end of the cable is getting 5 volts from your PC USB connector. The OpenEVSE project pages have good step by step instructions for using the programmer cable. If all that you want to do is to blast a new hex file into your OpenEVSE controller board then absolutely no knowledge of software nor programming is required. The steps involved boil down to this:
1) turn of AC to the OpenEVSE first for safety
2) connect the OpenEVSE programmer between laptop USB and the OpenEVSE controller board ISP pins
3) run the batch file that executes the download program which will erase the prior firmware and replace it with the new hex file (you may need to edit the batch file to give the correct name you have for the hex file)
4) if the J1772 is still connected to the car you want to disconnect it before restoring AC power to your OpenEVSE project. Cross your fingers now ;-)
5) after pulling the OpenEVSE programmer from the OpenEVSE ISP connection, restore the AC power and your OpenEVSE project should boot and run he self test as usual.
6) the V3 amperage display will show when the EV is connected again and charging.

If you have an OpenEVSE 30A project the best approach could be to buy the 30A to 50A conversion kit and also a polycarbonate enclosure and a new J1772 cable. If you do that then you'll end up with a nice 50A project in the metal enclosure plus a 30A convenience charger in the polycarbonate enclosure for backup or for carrying in your EV for travel. Thinking about it also get a new NEMA 15-50 plug for the 30A travel kit so you make the travel kit most versatile on the road.

If you haven't built the 50A kit with the contractor then do it. You will love it.

[Craig Kirkpatrick]

Another thought: Get yourself a USB extender cable from a local store that sells stuff for PCs. That way you have a nice long cable from your laptop to the OpenEVSE programmer when it is connected to your OpenEVSE project. You can get it to work without the extender cable but if you get an extender cable you will thank me for that advice.

[Craig Kirkpatrick]

Photos now for fun.

[James Klafehn]

Thank you. I do have a programmer and Chris has emailed me a few hex files to fit my needs.

Yes I have built a few portable, dual voltage kits now. I have been using the chinese relays because they allow dual voltage. I use my portable evse for 110 and 220. Here are couple of my builds.
http://s59.photobucket.com/user/jimbo69ny/library/Dual%20OPENEVSE%20Builds
http://s59.photobucket.com/user/jimbo69ny/library/High%20power%20portable%20OpenEVSE%20Builds

Will Chris' CT coil work with this display? This one here,
http://store.openevse.com/products/current-measurement-transformer-kit

I just ordered the Chinese display. It will probably take 3-4 weeks to arrive so I have a little time to plan.

Do you have a link to the HEX file you posted? I couldnt find it.

How does the display get connected to the EVSE? It looks like there are only 4 wires. 2 are for the CT coil. Are the other two 12v dc?

Thanks for your help!

On Sat, Nov 8, 2014 at 9:29 AM, Craig Kirkpatrick <crai...@comcast.net> wrote:

Another thought: Get yourself a USB extender cable from a local store that sells stuff for PCs. That way you have a nice long cable from your laptop to the OpenEVSE programmer when it is connected to your OpenEVSE project. You can get it to work without the extender cable but if you get an extender cable you will thank me for that advice.

--
You received this message because you are subscribed to the Google Groups "OpenEVSE" group.
To unsubscribe from this group and stop receiving emails from it, send an email to openevse+u...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[James Klafehn]

 I just noticed your photos, your display shows the amperage! Thats what I would like to do to. What is the 13 figure? Is that total Wh from the wall?

I thought I had to have this Chinese relay in order to get all this info.

On Sat, Nov 8, 2014 at 10:45 AM, Craig Kirkpatrick <crai...@comcast.net> wrote:

Photos now for fun.







Best Wishes,
Craig Kirkpatrick

On Nov 8, 2014, at 6:29 AM, Craig Kirkpatrick <crai...@comcast.net> wrote:

Another thought: Get yourself a USB extender cable from a local store that sells stuff for PCs. That way you have a nice long cable from your laptop to the OpenEVSE programmer when it is connected to your OpenEVSE project. You can get it to work without the extender cable but if you get an extender cable you will thank me for that advice.

--
You received this message because you are subscribed to a topic in the Google Groups "OpenEVSE" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/openevse/K_iqvvT1t48/unsubscribe.
To unsubscribe from this group and all its topics, send an email to openevse+u...@googlegroups.com.

For more options, visit https://groups.google.com/d/optout.

--
You received this message because you are subscribed to the Google Groups "OpenEVSE" group.
To unsubscribe from this group and stop receiving emails from it, send an email to openevse+u...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[Craig Kirkpatrick]

Jim,
The numeral 13 in the photo of my project while charging shows the time of day according to the real-time-clock. I did not set the time of day so it is 13 minutes after I switched on the circuit breaker.

Maybe I'll get motivated to remove the RTC code and timer code and replace it with instantaneous Watts and accumulated WattHours. Hmm, maybe event better would be accumulated WattHours and accumulated $.¢¢ with some menu to enter the electrical rate from the utility company. That is more valuable and entertaining to look at since the EV cars seem smart enough to handle delayed charging on their own, not needing the EVSE RTC to support it.

Thanks for helping me clearly see a motivation for diving back into the code. I'm having fun re-learning software skills that I put on the shelf back in 1989.

Best Wishes,
Craig

[Mark Moorcroft]

I agree, that the delay code could be better used program space on most setups.

[vegasbrad]

Craig, thanks for sharing! I just fired up my 3rd build tonight built around a v3 board I bought just because of the integrated current display. YEP that thing is very spazmatic! It needs help. I will try your code and post back, thanks soo much

[vegasbrad]

To help other Arduino newbies I did the hard parts and copied the linked .ino text into a folder then added all the required support files as well as the linked "H" file. i zipped it and attached here. I also edited the current tables to what my new EVSE will use. PS if you don't have WinRar get it now. way more powerful then just a zip program and widely used.

[Craig Kirkpatrick]

Brad, thanks for making this easier for folks. I was extremely limited in free time last week but wanted to share my changes asap.
Best Wishes,
Craig

[vegasbrad]

Craig, it was perfect, I knew just enough to make it work and want to help other Ardunino newbies like myself get a leg up. Thanks again for sharing, im going to run outside and try it now on my LEAF

[vegasbrad]

just tested, worked great on my LEAF!!!

[Craig Kirkpatrick]

Wonderful news to me since I had no other feedback about folks testing the small improvements I made. It would be interesting to somehow compare measurement accuracy from one build to another. I have a small panel meter with a CT that presently is at my circuit breaker box. I put some scale factors in the OpenEVSE code so that I got good measurement correlation between my EVSE and that meter. I have another V3 board and CT from the OpenEVSE store that I want to use to retrofit my 30A build so I get to see amperage on that one too. I probably won't have time to play with it until two weeks from now during our Thanksgiving holiday. And if I get time I'll also try to add the feature of showing money spent on electricity during a charge - that will let me learn how to interact with the button and display user-interface.

Brad, the Leaf charges at about 28Amps? Or does it have a 10kW charger thus drawing almost 40A?

Best wishes,
Craig

[vegasbrad]

Yep about 27.5. its a 6.6Kw charger (input side) i believe 6.0Kw output to batt pack.
Unfortunatly i just noticed something, the time and delay time are missing from the menu now.

[vegasbrad]

I just DL the individual files and created a ez self executable folder like Chris's HEX's are, unfortunatly it has the same problem, missing time and delay time in menu.
i posted the zip incase it helps anyone

[Craig Kirkpatrick]

Brad, I also noticed the RTC functions are not completely working on my V3 like they work on my V2. I don't use the RTC much since I can set charge times in my Ford EV so I made no attempt to debug it. I believe it was like this before my minor enhancements to the Amperage measurements. Chris has a released V3 hex file on the OpenEVSE store that could put you back to the code without my current measurement smoothing enhancement. Testing that for proper RTC operation will tell if I somehow buggered things. Like I said, I think I saw problems there before I even worked on the amperage smoothing function which did not touch any real time clock code.

I won't have time to investigate this until Thanksgiving.

Best wishes,
Craig

[civicturbo _]

I loaded Chris's HEX off the v3 board's homepage and the RTC is back, but when i DL the firmware source from github (v3.2.2)  they call it rapi, compile & load, then the RTC is gone again, so i agree something is funny.

> Date: Fri, 14 Nov 2014 14:01:30 -0800
> From: crai...@comcast.net

> To: open...@googlegroups.com
> Subject: Re: OpenEVSE Plus v3 and Current Measurement
>

[chris1howell .]

Nothing funny... The RTC code is a really horrible RAM hog. So if CLI or RAPI is enabled RTC gets disabled.

--

You received this message because you are subscribed to the Google Groups "OpenEVSE" group.

To unsubscribe from this group and stop receiving emails from it, send an email to openevse+u...@googlegroups.com.

[Craig Kirkpatrick]

Chris, thanks. Brad, if you want to go into the OpenEVSE.h file you can disable the API things and the RTC should work OK again. I won't have time to mess with this for a week or more.

[lincomatic]

Actually the RTC support isn't disabled when RAPI is enabled, but the button menus on the LCD are. And that's because of RAM issues, as Chris stated. But it's not RTC that's disabled when RAPI enabled, but DELAYTIMER_MENU ... so the menus go away, because they're huge. The web interface I'm working on actually uses the timer functions still, but are configured via a web browser instead of the LCD.

-----Original Message-----
From: open...@googlegroups.com [mailto:open...@googlegroups.com] On Behalf Of Craig Kirkpatrick

Sent: Friday, November 14, 2014 3:10 PM
To: open...@googlegroups.com
Subject: Re: OpenEVSE Plus v3 and Current Measurement

[vegasbrad]

Very interesting. What should I change in the code to get the RTC back? I won't be using any rapi on this unit.

[lincomatic]

just comment out RAPI in open_evse.h

 

//#define RAPI

[civicturbo _]

cool, ill try that

---

From: linco...@gmail.com
To: open...@googlegroups.com
Subject: RE: OpenEVSE Plus v3 and Current Measurement
Date: Fri, 21 Nov 2014 23:08:38 -0800

You received this message because you are subscribed to a topic in the Google Groups "OpenEVSE" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/openevse/K_iqvvT1t48/unsubscribe.
To unsubscribe from this group and all its topics, send an email to openevse+u...@googlegroups.com.