Inaccurate Readings

[Chuck]

[Chuck]

Ok, your forum software is very weird.  I wrote a whole message and then attached a picture and all that seems to have made it through is the picture.  Apparently you can’t have both messages and text in the same forum posting.  Here is the text that should have accompanied the previous posting:

 

I recently installed the Vue and have been getting some very inaccurate readings.  My house is equipped with Solar, so I set up my Vue with that in mind.  At the present time I only monitor the whole house.  I am on PGE, and I have their smartmeter that gives me real time readings as well as cumulative readings.  While most of the time the Vue seems to be tracking with the smartmeter, there are times the Vue is WAY OFF.  On a daily basis the Vue is very inconsistent, sometimes showing a total that is almost the same as what the smartmeter says, but other days it is way off.  For example, on the 16th PGE showed I used a -10KWh, while the Vue shows -4.3Kwh.  On the 15th PGE shows -6Kwh and the Vue shows -6.08.  This continues, some days are very accurate, some days are not.  I am positive I have the sensors connected correctly.  I will try to attach a picture to this message.  Not sure what to do about this.  I have reset the Vue a couple of times, didn’t seem to help the accuracy at all.  When I do a spot check of  the Vue against the smartmeter most of the time it is very close, but other times it isn’t close at all.

[Chuck]

Here is some additional information regarding the inaccurate readings I seem to be getting from my Vue.  Since I am unable to attach a picture to this message without destroying the message itself, I will post a screenshot in a post following this one.  What the screenshot shows is that my Vue was reporting around 2.35KWH being used at around 10:03am.  I knew this was wrong because I could look at my PGE smartmeter and it was showing a -3.1KWH reading.  I know the smartmeter is correct because my Solar Panels were hard at work and I was PRODUCING more electricity that I was using.  Yet the Vue was showing I was CONSUMING.  However, as the screenshot shows, within a minute or two the Vue suddenly FLIPPED the reading, showing that I was, indeed, PRODUCING around -3.1KWH.  This strange behavior would certainly explain why my Vue’s daily readings are sometimes way off from what PGE shows.  Why do you think it “FLIPPED” like that?  Is it a processing problem at your end?  As it is, the Vue is worthless as far as giving me accurate readings on a day by day basis.

[Chuck]

[Chuck]

One last thing … here are the readings for the last 8 days from the Vue, as compared to what PGE says I used on that same day:

Date          PGE            Vue

02/17         -7.48            -2.89
02/16        -9.62             -4.32
02/15        -6.16             -6.08
02/14        -9.00            -2.95
02/13        -8.95            -8.05
02/12        -6.99            -6.90
02/11         -5.38               .07
02/10       -10.06          -5.04

As you can see, over a 8 day period the Vue was inaccurate more than 60% of the time.   I’m not concerned with the data being a little off, such as what you see on 2/15, 2/13 and 2/12.  I’m concerned about the other days that are off by a HUGE amount!

Thanks,  Chuck

 

[Marty @Emporia]

Hello @Chuck,

Thank you for the detailed information on your Vue readings and the comparison to your PG&E readings.    I have forwarded this information on to our developers, as you have certainly pointed out some clear discrepancies.   We will be following up as soon as we have more information to share with you.   In the meantime, please feel free to reach out to us if you have any further questions or concerns.

– Marty

[Marty @Emporia]

Hello @Chuck, we are still looking into this.   Do you continue to see these type of discrepancies?

[Chuck]

Hi @Marty … well, I can’t really say since I have went in a different direction.  When I purchased the Emporia Vue I had originally wanted to monitor my CONSUMPTION.  The Solar output was not really important to me, since Enphase provides that (although on a much delayed basis, typically at the end of the day).  I tried the net metering thing with the Vue and found it was not accurate (as detailed above).  Also, the electrical panel I have is VERY TIGHT on space, so putting the main sensors anywhere but at the top of the breakers (above the Main & Solar breakers) was not really an option.  Since that time I have purchased the 200a spring clamp sensors you offer on your web site.  Using these sensors I was able to get them BETWEEN the main/solar breakers and my house breakers.  In this position they give me my house’s CONSUMPTION, and it seems to be pretty accurate.  I then took one of the 50a sensors and attached it to the Solar feed and then ran that sensor to the expansion module.  This gives me my solar output.  It would be nice to have an option to automatically combine the main and Solar readings, but it’s not a big deal to subtract the two and give me the net and compare to what my PGE smartmeter says my net is at any given time.  As long as the Vue gives me daily totals it will work.  However, since going to this configuration I have run into the same problem that @kk07 reported in the “Are small clamps from expansion module bidirectional?” thread in Support Center.  My Solar installation uses Enphase microinverters (41 of them), and when the system is offline (i.e. at night) the Vue recorded 408 watts (@120v) “phantom” power being sucked up by the inverters, which will throw the daily solar readings off.  I wish there was a way around this.  I didn’t have time yesterday, but tonight, after the sun goes down, I plan to use my clamp on amp meter and see what it says about the circuit after the sun goes down.  I assume there must be a way around this, since PGE’s smart meter doesn’t seem to “see” this phantom power usage.

I think this phantom power use was throwing the power consumption reading off after the sun went down in my old (net metering)  configuration.  I was showing about 300-400 watts higher at night than what PGE’s smartmeter was showing.

Thanks,  Chuck

 

[Chuck]

After the sun went down I went out to the electrical panel (mine is on the outside of the house) and used my clamp on amp meter to check both legs of the Solar lines.  Both read around 3.3 amps on my meter.  The Vue, which is monitoring only one leg of the feed, shows -6.69 amp, which is basically 3.3 amps per leg (I use a 2.0 multiplier).  So there is power being measured, so I’m not sure what you (emporia) can do about it with regards to the Vue hardware & software.

I’m curious if this is real power being consumed and (if so) does the PGE smartmeter record it?  If it is I have roughly 12 hours of 6.69 amps @ 240v being drawn from the grid by my solar panels.  That would be about 19.2KWh PER DAY being drawn from the grid.  Can’t believe that would be true, so I’m wondering why the PGE smartmeter doesn’t “see” the power flowing through the Solar lines.  I have read Steve’s Blog where he talks about night time “sleeping” load on connected inverters, but not sure I fully understand it.  In order to test whether or not the smartmeter sees (and records) the power I would probably have to kill all the breakers in my house for a couple of minutes to eliminate all the load except for the Solar panels.  I’ll try to do that sometime when it won’t disrupt what the wife is doing in the house.

In any case, I sure wish there was a way to ignore the “apparent power” being consumed by the inverters.  If the power isn’t being measured by the PGE smartmeter then their must be a way to do it, but I would image it would take something in hardware/firmware to accomplish it.

Chuck

 

[GlennC]

I am also seeing low readings from my recently installed Vue.  My first bill that I was able to compare stated I had used 813 kWh, and the exported Vue data was 655 kWh. This is about 80% of the utility reading.

 

 

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