EVSE Charging Power Monitoring with EKM

[garygid]

In response to questions in the OpenEVSE thread,
I decided to investigate the monitoring and logging or
power usage usiing the EKM devices and software.
I started this thread to avoid poluting the OpenEVSE thread.

1. Testing the EKM Dash (dashboard, Beta) software,
using their 30 day free, full-fuction trial.

 

[garygid]

EKM Dash Software:

In case you want to try the EKM Dash (Beta) software
for reading and logging their remote ELM demo meters,
here is what I tried.

Download their ZIP file from:
http://www.ekmmetering.com/ekmdash" onclick="window.open(this.href);return false;
instructions at:
http://documents.ekmmetering.com/EKM_Dash_Setup_Instructions.pdf" onclick="window.open(this.href);return false;

I downloaded the Windows version onto my Vista laptop,
into an ELM folder that I made on my more roomy D drive.

Unzip the ZIP file, and Run the ".exe" file, and choose the
30 day free trial option.

The EKM Dash overvies or description:
http://www.ekmmetering.com/ekmdash" onclick="window.open(this.href);return false;
says that the Beta comes pre-configured with their demo meters,
but you see no meters.

So, click the Meter icon and choose "New Meter", which provides
a dropdown list of the EKM demo meters. I chose the "Meter #3093 (25EDSP)",
which the preconfiguration says is meter model "25eDSP-N v2".
You can see that it is Remote, apparently located at meters.ekmmetering.com
and Meter serial number 3093, with (apparently) ID or port 50000.
Note that it will Query the meter every 5 seconds.

After clicking OK to add this meter to your (empty) list of meters,
click the green "Start Reading" icon, and watch the data come in.

Comments on the data:

Viewing data as a graph:

Logging the data:

Viewing the Logs:

 

[garygid]

Connections:

Ethernet, Local or Remote

 

[garygid]

Connections:

RS-485

 

[garygid]

240v Meters

------
Wire(s) Passing Through Meter:

Some of these meters require a Neutral, but I think that at least one does not.
For example, this one might work well inside the EVSE: for use with
Single-phase 120 or 240 Volt, 3-wire 60Hz, the EKM-25IDS-N v.2
http://www.ekmmetering.com/ekm-metering" onclick="window.open(this.href);return false; ... s-nv2.html

Even though it mentions 3-wire, it appears to be for a 120v or 240v
single phase (2-wire) circuit, which is exactly what the EVSE uses.

------
Using Current Transformers (CTs):

 

[garygid]

Misc 1

 

[garygid]

Misc 2

 

[waidy]

I am not able to download a csv file. If you are able to download one, would you provide a URL for download? I would like to see what data is provided in the csv file. Thank you.

 

[waidy]

The meter needs voltage inputs and current inputs that can be obtained directly from the line side of the EVSE (at the EVSE or junction box). Small donut-shaped current transformers around the supply conductors provide the current inputs. Voltage inputs come from connections to the line side conductors also. The voltage inputs should be fused with 1 ampere inline fuses to protect the meter and the small wires going to it. The meter is powered from the voltage inputs so it does not need a separate low-voltage power supply but it will need the neutral conductor in addition to ground and line conductors. I have been using a couple of EKM meters to monitor my Leaf power consumption and the power usage at my workshop garage for several months, but have not yet tried data logging. I will be looking at the thread Gary started for tips on the software and RS-485 connections.

Gerry

Oh no, I told my electrician not to feed a neutral to the EVSE. However, my ground wire is upsized from 8awg to 2awg (yes, I will have 3 2awg wires:red,black,green). The reason for using 2awg wiring is because I have several wheels of 2awg wires left over from the construction of my home.
Ouch, Ouch.. I guess I will have to use 2Awg Black, 2Awg Red, 8Awg Green, and 8Awg White. By the way, the OpenEVSE geniuses said the OpenEVSE doesn't take neutral. Oh, I am so confuse.

 

[garygid]

True, the OpenEVSE does not use or require a Neutral (usually white) wire.

Some of these meters require a Neutral, but I think that at least one does not,
for example this one might work well in the EVSE:
for use with Single-phase 120 or 240 Volt, 3-wire 60Hz, the EKM-25IDS-N v.2
http://www.ekmmetering.com/ekm-metering-products/electric-meters-kwh-meters/single-phase-energy-meter-for-120-240-volt-3-wire-60hz-ekm-25ids-nv2.html" onclick="window.open(this.href);return false;

What csv file?

 

[QueenBee]

True, the OpenEVSE does not use or require a Neutral (usually white) wire.

Some of these meters require a Neutral, but I think that at least one does not,
for example this one might work well in the EVSE:
for use with Single-phase 120 or 240 Volt, 3-wire 60Hz, the EKM-25IDS-N v.2
http://www.ekmmetering.com/ekm-metering-products/electric-meters-kwh-meters/single-phase-energy-meter-for-120-240-volt-3-wire-60hz-ekm-25ids-nv2.html" onclick="window.open(this.href);return false;

What csv file?

You will not need a neutral to use the EKM meters. The one Gary linked to above will use just your two hots. It supports .375" diameter wire and that appears to be about the size of #2 wire so you should be good.

In fact if you were making a portable unit to operate at 120 volt or 240 volt you could get their Omnimeter with 1 CT and it would measure at either 120 volt or 240 volt:
http://www.ekmmetering.com/ekm-omnimeter-i-v-3-3-phase-3-wire-or-4-wire-120-to-480v-50-60hz-single-phase-2-or-3-wire-120v-to-480v-50-60-hz.html?___store=default" onclick="window.open(this.href);return false;

 

[GerryAZ]

Waidy,

Which EKM meter do you have? Is your installation for a standard 120/240-volt single-phase circuit? If so, depending upon which meter you have (or intend to purchase), you may not need the neutral. Using the larger ground wire for your EVSE is good because harmonic filters in the onboard charger (and EVSE if so equipped) dissipate to ground. After you answer the questions, I will look at possible meter connection configurations and offer more recommendations.

Gerry

 

[waidy]

Waidy,

Which EKM meter do you have? Is your installation for a standard 120/240-volt single-phase circuit? If so, depending upon which meter you have (or intend to purchase), you may not need the neutral. Using the larger ground wire for your EVSE is good because harmonic filters in the onboard charger (and EVSE if so equipped) dissipate to ground. After you answer the questions, I will look at possible meter connection configurations and offer more recommendations.

Gerry

I haven't gotten one yet. I am in the research stage looking for a power monitor that has data logging. I am also waiting for GaryGID's and others' reviews At this point, I want to do as much prep work (wiring) as possible while I am installing the EVSEs. So far the EKM-25IDS-N looks promising. If it split out a csv file that contain event triggers I will get it.

 

[waidy]

I should add the reason why I want event trigger is because I want to be able to write a script to produce a chart/graphs to show "start time, end time, hours charge, kWh juiced". Below is an example of my charging history since Feb 2011. I used 7.841MWh (7,841,000 kWh) in transportation since Feb 2011. The 7.841 MWh usage does not include my 2002 Rav4EV or any outlets (120V and 240V) I used on any "opportunity charging" locations. It also does not include the superchargers.
The 7.841 MWh driving represents a GHG savings of 11,142 kg or 1,638.75 Gallons of gasoline.

 

[garygid]

The meters generally respond to queries over the RS-485 bus,
and send data out, generally to the request.

So, a communication connection is needed to some program that
makes the queries, perhaps every 5 seconds, and gathers the results.

The RS-485 can end in an RS-232 serial port, or a USB port that
creates a virtual Comm Port in the computer, or an Ethernet
connection. The data is requested and captured by a program
like the EKM Dash program, which appears to hold the data in
memory until the user Exports the data to a CSV file. I did not see
a way to set up periodic auto-Export (file writing) but that might
be (should be) planned for the future.

Manually, you might write a file once a week or so, but I do not
yet know what the data capture-size limits are.

 

[garygid]

Event triggers:
Presumably you want these Events to be Start or End charging.

One could easily process the EKM CSV file to aggregate the data
into continuous "off" (below some charging-related threshold)
and "on" (during charging) periods.

Then, the resulting data would be just Start events, and Stop events.,
which would be very close to what you graphed above.

 

[garygid]

If you do not want to have a computer always on to
Qurey and collect the data, the EKM Push system can
collect the data in the Cloud, and you can download
the collected data at your inconvenience, with EKM Dash,
Export the data to a CSV file, just as if you had collected
it locally.

Then process the power flow into Start-Stop events, with
total energy, and date-time information, easy to graph.

I think that EKM says that the Dash program will
accumulate and summarize the data periodically,
and email the results. I have not yet found that
part of the program. Or, was that a Cloud function,
when using the Push system?

 

[GerryAZ]

Waidy,

Which EKM meter do you have? Is your installation for a standard 120/240-volt single-phase circuit? If so, depending upon which meter you have (or intend to purchase), you may not need the neutral. Using the larger ground wire for your EVSE is good because harmonic filters in the onboard charger (and EVSE if so equipped) dissipate to ground. After you answer the questions, I will look at possible meter connection configurations and offer more recommendations.

Gerry

I haven't gotten one yet. I am in the research stage looking for a power monitor that has data logging. I am also waiting for GaryGID's and others' reviews At this point, I want to do as much prep work (wiring) as possible while I am installing the EVSEs. So far the EKM-25IDS-N looks promising. If it split out a csv file that contain event triggers I will get it.

From your answers and rereading your previous posts, I am guessing your installation is at home on a standard 120/240 circuit. If so, then you do not need the neutral for the 25IDS-N. Since that meter has internal CTs, the maximum wire diameter it will work with is about 3/8 inch. I don't know if you will be able to get the 2 AWG wire through its openings. If you are using standard type THHN or THWN building wire, it will be a tight fit. The alternative is the EKM Omnimeter which uses external donut current transformers and fused voltage inputs. There are different ways to connect it using either 1 or 2 current transformers and 1 or 2 voltage inputs. If you use 1 current transformer and 1 voltage, you do not need neutral. If you use 2 current transformers, then you need 2 voltage inputs which means you need the neutral. I suggest you download the manuals for the meters from EKM's web site and look at the different possibilities. There is a lot of good information there. If the conduit for your circuit has not been installed, why not go with one size larger and have the neutral pulled in? That would also allow you to have a NEMA 14-50 receptacle installed (instead of hard wiring) if a future EVSE required that type of connection.

Gerry

 

[waidy]

Event triggers:
Presumably you want these Events to be Start or End charging.

One could easily process the EKM CSV file to aggregate the data
into continuous "off" (below some charging-related threshold)
and "on" (during charging) periods.

Then, the resulting data would be just Start events, and Stop events.,
which would be very close to what you graphed above.

Yes, this is my plan. The TED I have at home can only output 1 day of event by second or by minute (which I understand why. It is because the sec and min events are just too much data to store). If I could export the data everyday.. well, I failed :-( There is no API for me to write a tool for nightly download :-(

Now back to the EKM-25IDS-N ($140), since there is no mac address assigned to the unit I will have to get a EKM RS-485 to USB Converter ($20) + wireless access point with USB2Ethernet cable. I guess I have to get their EKM Dash SW ($30). So the setup is do-able.

Perhaps I should give them a call tomorrow and ask for a sample CSV file.

 

[waidy]

[
From your answers and rereading your previous posts, I am guessing your installation is at home on a standard 120/240 circuit. If so, then you do not need the neutral for the 25IDS-N. Since that meter has internal CTs, the maximum wire diameter it will work with is about 3/8 inch. I don't know if you will be able to get the 2 AWG wire through its openings. If you are using standard type THHN or THWN building wire, it will be a tight fit. The alternative is the EKM Omnimeter which uses external donut current transformers and fused voltage inputs. There are different ways to connect it using either 1 or 2 current transformers and 1 or 2 voltage inputs. If you use 1 current transformer and 1 voltage, you do not need neutral. If you use 2 current transformers, then you need 2 voltage inputs which means you need the neutral. I suggest you download the manuals for the meters from EKM's web site and look at the different possibilities. There is a lot of good information there. If the conduit for your circuit has not been installed, why not go with one size larger and have the neutral pulled in? That would also allow you to have a NEMA 14-50 receptacle installed (instead of hard wiring) if a future EVSE required that type of connection.

Gerry

Hi Gerry, It is my plan to have 3x2awg wires: Black,Red,Green for each of the OpenEVSE. It is 240V and 100Amp breakers. I already have 14-50, 10-50, and 6-50 outlets (among other L6-20, 10-30, etc.) inside my garage so I don't need another 14-50. RTFM is a good suggestion, and I will do that. Thanks for pointing this out.