Author Topic: Having TED ignore a line load?  (Read 6955 times)

Jimmydreams

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Having TED ignore a line load?
« on: March 04, 2011, 04:57:07 PM »
I believe someone has solved this before, and I want to make sure I'm doing the right thing before I continue...(the info is gone with the old support forum)

I have 2 CT's monitoring my main house power.
I have 2 CT's monitoring the line that goes to my Electric Vehicle (EV).

I want TED to show me the main house usage but IGNORE the power going to the EV since it's already being monitored by a separate set of CT's.

I believe it was determined that if I run the power wires for my EV back through the CT's for the main house, that this would cancel out the reading for the EV line....IOW, the main CT's reads X power coming in for the EV, but then reads that same power going the opposite way back through the same CT's, thus the outgoing power negates the incoming power. The main CT's won't show a value if they read the same power going though it in each direction by 2 different sets of wires and since I have another set of CT's reading just the EV line, I can have that value separated out from the main house load.

To make it even easier.....if I run two sets of wires through the same CT; wire A has power running 'in' and wire B has power running 'out'. If wire A is running 500 watts and wire B is running 200 watts, then the CT will register 300 watts and not 700 watts.

Is this understanding correct??

Thanks in advance.

Jim
« Last Edit: March 04, 2011, 08:16:29 PM by Jimmydreams »

Certified Solar

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Re: Having TED ignore a line load?
« Reply #1 on: March 07, 2011, 05:15:03 AM »
Firstly I have to admit to not understanding the problem fully. But it seems to me that handling this in the Setup settings for the MTU is the most straightforward solution. Set anything you want TED to track but not roll into the net as Standalone. That way your hardware setup doesn't get complicated.

TEDSupport6

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Re: Having TED ignore a line load?
« Reply #2 on: March 07, 2011, 10:25:33 AM »
CertifiedSolar is correct. Connect the CTs from MTU1 around the main leads from your utility and the CTs from MTU2 around the lines feeding your EV. Go to Edit > System settings wizard > System layout tab, and modify the MTU configuration so that MTU1 is set as LOAD and MTU2 is set as STAND ALONE. The readings from MTU2 will not be added into your cumulative total this way.

Jimmydreams

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Re: Having TED ignore a line load?
« Reply #3 on: March 07, 2011, 10:41:58 AM »
CertifiedSolar is correct. Connect the CTs from MTU1 around the main leads from your utility and the CTs from MTU2 around the lines feeding your EV. Go to Edit > System settings wizard > System layout tab, and modify the MTU configuration so that MTU1 is set as LOAD and MTU2 is set as STAND ALONE. The readings from MTU2 will not be added into your cumulative total this way.

I'll try that (I thought I tried it before and it didn't work, but....)

I have solar with a 3rd MTU on the solar.

MTU1 on Main set as NET
MTU2 on solar set on Generation
MTU3 on EV set to STAND ALONE

The problem lies in that MTU 3 is 'downstream' from MTU1...IOW, any power that goes through MTU3 will have already passed through MTU1. So MTU1 reads the power that is also read on MTU3. I'm trying to have MTU1 ignore the load on MTU3.

???

TEDSupport6

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Re: Having TED ignore a line load?
« Reply #4 on: March 07, 2011, 11:06:40 AM »
Quote
MTU1 on Main set as NET
MTU2 on solar set on Generation
MTU3 on EV set to STAND ALONE

This setup should work for you. Does your solar feed back through your main panel (MTU1) also? You can take a look at this post to make sure you have your system configured correctly: http://forums.theenergydetective.com/index.php/topic,13.0.html.

Jimmydreams

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Re: Having TED ignore a line load?
« Reply #5 on: March 07, 2011, 11:51:00 AM »
Quote
MTU1 on Main set as NET
MTU2 on solar set on Generation
MTU3 on EV set to STAND ALONE

This setup should work for you. Does your solar feed back through your main panel (MTU1) also? You can take a look at this post to make sure you have your system configured correctly: http://forums.theenergydetective.com/index.php/topic,13.0.html.

My solar feeds back through MTU1, as does the EV circuit. My setup is just like scenario A.

MTU1 reads all power in/out of the main breaker panel. MTU2 for solar reads solar production that feeds into the main breaker panel. MTU3 reads power going from the  main breaker panel to the EV charger. If we need pics, I can easily get them.

I'll try changing the MTU settings to set MTU3 as STAND ALONE and see if that forces Footprints to subtract MTU3 numbers from MTU1. I'm faily sure I did that before, but that was also before the software upgrade.  ::)

Jimmydreams

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Re: Having TED ignore a line load?
« Reply #6 on: March 07, 2011, 05:57:11 PM »
Quote
MTU1 on Main set as NET
MTU2 on solar set on Generation
MTU3 on EV set to STAND ALONE

This setup should work for you. Does your solar feed back through your main panel (MTU1) also? You can take a look at this post to make sure you have your system configured correctly: http://forums.theenergydetective.com/index.php/topic,13.0.html.

My solar feeds back through MTU1, as does the EV circuit. My setup is just like scenario A.

MTU1 reads all power in/out of the main breaker panel. MTU2 for solar reads solar production that feeds into the main breaker panel. MTU3 reads power going from the  main breaker panel to the EV charger. If we need pics, I can easily get them.

I'll try changing the MTU settings to set MTU3 as STAND ALONE and see if that forces Footprints to subtract MTU3 numbers from MTU1. I'm faily sure I did that before, but that was also before the software upgrade.  ::)

Well, I have MTU 1 set for Adjusted Load, MTU 2 set for generation, and MTU 3 set for Stand alone and it still counts the energy going into MTU 3 in to total. I've tried MTU3 as Stand Alone (net), as well as reversing the CT's to show a negative number.

I guess I'm back to my original question: if a CT has 2 wires going through it sending power in different directions (one wire sending power 'in' and one wire sending power 'out'), does the CT read the difference between the two? IOW, if both wires have 500 watts (going each direction), does the CT read zero watts because they cancel each other out? Also, if one wire shows 500 watts and the other 300 watts, does that CT read 200 watts?

If I can't make Footprints do what I want, I'll physically run the wire back through the CT to cancel out the incoming power....but that means I have re rewire part of the panel. I don't want to do that it if it's not going to do what I want.

TEDSupport6

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Re: Having TED ignore a line load?
« Reply #7 on: March 09, 2011, 07:02:28 AM »
Quote
if a CT has 2 wires going through it sending power in different directions (one wire sending power 'in' and one wire sending power 'out'), does the CT read the difference between the two? IOW, if both wires have 500 watts (going each direction), does the CT read zero watts because they cancel each other out? Also, if one wire shows 500 watts and the other 300 watts, does that CT read 200 watts?

Yes, this is why the CTs are polarized. Setting up your system this way is very tricky, because the direction of the CTs and your wires must be very specific. I recommend opening a support ticket so that you can work directly with a technician to make sure that you get it configured correctly: http://www.theenergydetective.com/support/tickets.

SherlockOhms

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Re: Having TED ignore a line load?
« Reply #8 on: March 09, 2011, 07:40:12 AM »
Please post a picture/diagram of how everything is connected physically.  In particular, is EV on it's own breaker? If so then it's fine, just set it as stand alone. It doesn't need to be subtracted. It will be just ignored as it has already been measured through the NET (MTU1)

Jimmydreams

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Re: Having TED ignore a line load?
« Reply #9 on: March 09, 2011, 09:34:32 AM »
Quote
if a CT has 2 wires going through it sending power in different directions (one wire sending power 'in' and one wire sending power 'out'), does the CT read the difference between the two? IOW, if both wires have 500 watts (going each direction), does the CT read zero watts because they cancel each other out? Also, if one wire shows 500 watts and the other 300 watts, does that CT read 200 watts?

Yes, this is why the CTs are polarized. Setting up your system this way is very tricky, because the direction of the CTs and your wires must be very specific. I recommend opening a support ticket so that you can work directly with a technician to make sure that you get it configured correctly: http://www.theenergydetective.com/support/tickets.


I opened a ticket at Rich's request. Abbi Russo simply closed the ticket without any commentary whatsoever. A simple "see the forum post" might have been better..... anyway, I just spoke to Joey and he said the same thing you did; that the power going out on circuit 3 (the EV circuit) will effectively be cancelled out if it's run back through CT1. I'm going to try that to see how it works. The system works just fine already with my solar, so MTU1 CT's are situated properly.  ;D

Please post a picture/diagram of how everything is connected physically.  In particular, is EV on it's own breaker? If so then it's fine, just set it as stand alone. It doesn't need to be subtracted. It will be just ignored as it has already been measured through the NET (MTU1)

I'll post a picture when I get one. I'm sure sooner or later, this will come up again, so I want this thread to be as accurate as possible.

Jimmydreams

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Re: Having TED ignore a line load?
« Reply #10 on: March 11, 2011, 12:06:23 PM »
For those of you keeping score:

I ran the wires for my EV back through the CT's for MTU1, effectively nulling that load. I have CT's on the EV circuit, and everything is working GREAT!

Here's a screenshot:

The red line is my main house (MTU1). The green line at the bottom is my solar generation (MTU2), and the bluish-green line that spikes is my EV (MTU3) that I just plugged in.

You can see that the red line (MTU1) basically 'ignores' what's going on on MTU3, even though MTU3 circuit is pulling 3.6kW!! This is exactly what I was looking for. Now I can graph out and track MTU3 completely separately from MTU1 and MTU2 (which run the net-metering for my home/solar)

I'm a very happy camper.   ;D