My System Efficiency is 81.3%. Prove me wrong or show me your math.

[GregTR]

Were you able to separate out resistive loads? Those, I expect inverter to meet specs.

I did by subtracting the base from the power in those equations above. I was still at 4.5% difference between what the Sol-Ark measured and what my Emporia/smart meter measured.

 

[Hedges]

Leaving 95.5%, which is about the battery to AC spec (at 65% load)
Maybe SolArk measures voltage and current feeding inverter, rather than having sensors to measure AC power? That would not include 48V battery to HV DC losses.

Do you have a clamp ammerter? That could measure AC RMS current (cheap ones less likely to be true RMS.) AC VA / Vrms = Irms. Watts may differ. But compare clamp measured Irms; if waveform isn't sine wave, has shorter higher spikes, that would have more I^2R loss in FETs and inductors compared to a nice "real" resistive load. Such a meter reading migh explain your results.

 

[SignatureSolarJames]

Leaving 95.5%, which is about the battery to AC spec (at 65% load)
Maybe SolArk measures voltage and current feeding inverter, rather than having sensors to measure AC power? That would not include 48V battery to HV DC losses.

Do you have a clamp ammerter? That could measure AC RMS current (cheap ones less likely to be true RMS.) AC VA / Vrms = Irms. Watts may differ. But compare clamp measured Irms; if waveform isn't sine wave, has shorter higher spikes, that would have more I^2R loss in FETs and inductors compared to a nice "real" resistive load. Such a meter reading migh explain your results.

Is Emporia revenue grade?

 

[cs1234]

Is Emporia revenue grade?

I wouldn't think so. I assume you already know this though and are being snarky. That would require +/- .5% accuracy, where Emporia claims a +/- 2%.

 

[SignatureSolarJames]

I wouldn't think so. I assume you already know this though and are being snarky. That would require +/- .5% accuracy, where Emporia claims a +/- 2%.

no snark, haven't looked into it
where do they claim 2%

 

[GregTR]

Is Emporia revenue grade?

I don't think so but the readings from Emporia were within 1% of my meter readings long before I installed solar.
Now there is a chance that they're not as accurate on the inverter produced AC than they are on the grid produced AC so there could be a difference there that I did not account for.

But even if that is the case, the discrepancy that Sol-Ark measures on the gid side compared to my meter still remains. My meter is definitely "revenue grade"

 

[cs1234]

no snark, haven't looked into it
where do they claim 2%

Emporia Vue Gen 2 product page.

REAL-TIME ENERGY DATA: REQUIRES 2.4 GHz WIFI WITH AN INTERNET CONNECTION to monitor energy use with iPhone / Android / Web app. Vue sensors provide 1-second data and are accurate from ±2%. The Vue is UL and CE Listed for your safety. 1 second data is retained 3 hours, 1 minute data is retained 7 days, 1 hour data is retained indefinitely. Export the data whenever you want in the app.

 

[robby]

REAL-TIME ENERGY DATA: REQUIRES 2.4 GHz WIFI WITH AN INTERNET CONNECTION to monitor energy use with iPhone / Android / Web app. Vue sensors provide 1-second data and are accurate from ±2%. The Vue is UL and CE Listed for your safety. 1 second data is retained 3 hours, 1 minute data is retained 7 days, 1 hour data is retained indefinitely. Export the data whenever you want in the app.

If he is using anything other than the 1 second data then his calculations are going to be off.
Tho Sol-Ark Powerview App takes readings at 5 minute Intervals Versus Solar Assistant at 2 second Intervals. A lot can change in 5 minutes and each time it adds up but then of course the averages may cancel??

Device ------- Dec ----- Feb
Powerview--- 367.6 ----- 302.2
Solar Asst-----361.6 ----- 304.2
This is Grid consumption values.

But it' hard to say what is happening because from time to time the Solar Assistant goes off line and data freezes and I have no idea how either of them do the math.
I assume they are holding the value at each data point as constant until the next data point.
I would imagine that at the 1 hour interval the total data from the Vue App would be useless in terms of accuracy unless it is still doing 1 second sampling and then adding it up and averaging before writing one data point and then resetting the temp cache for the next interval.

 

[GregTR]

If he is using anything other than the 1 second data then his calculations are going to be grossly off.
It like the Sol-Ark Powerview App at 5 minute Intervals Versus Solar Assistant at 2 second Intervals. A lot can change in 5 minutes and each time it adds up but then of course the averages may cancel??

Device ------- Dec ----- Feb
Powerview--- 367.6 ----- 302.2
Solar Asst-----361.6 ----- 304.2
This is Grid consumption values.

But it' hard to say what is happening because from time to time the Solar Assistant goes off line and I have no idea how either of them do the math.
I assume they are holding the value at each data point as constant until the next data point.
I would imagine that at the 1 hour interval the total data from the Vue App would be useless in terms of accuracy unless it is still doing 1 second sampling and then adding it up and averaging before writing one data point and then resetting the temp cache for the next interval.

I am fairly confident that Emporia knows how to integrate one second samples into 15 minute buckets. As I have stated before Emporia's 15 minute bucketed data matched my smart meter's data from my utility provider within 1% before I installed solar.

The last data I checked with EV charging last night was using the 10 second samples from Solar Assist and the 1 second data from Emporia and the difference was still 4.5% high on the Sol-Ark side for the EV charge portion of the power.

I mean I did talk with Emporia about some of the things they're doing not so great but accuracy was never my concern with the device and it is not my concern today.

I did try to put a clamp meter (I have a Fluke 325, should be accurate enough) on my load side output from the inverter to measure current along with the voltage but the wires were too crowded in the gutter and I didn't feel like removing my panel cover today. Maybe tomorrow I'll play with it some more but as things stand today I'll estimate my "effective" PV production as I had before:
"Effective PV" = Load (measured by Emporia) + Grid Export (measured by utility) - Grid Import (measured by utility).

Everything else is irrelevant in the grand scheme of things as the only PV that is of value to me is that finds its way to my load or to the grid.

 

[Hedges]

Everything else is irrelevant in the grand scheme of things as the only PV that is of value to me is that finds its way to my load or to the grid.

Understanding how types of loads affect the percentage of power you get to use could be relevant, if something like power factor is the culprit and you are able to change that.

"The first LED flood light has a power factor of 0.95 while the other has a power factor of 0.55. The LED with a power factor of .95 would draw approximately 0.092 Amps while the LED with a power factor of .55 would draw 0.16 Amps."

Power Factor Explained | LED Lights — 1000Bulbs.com Blog

Not all LEDs are created equal. Here's what you need to know about power factor and LED lights before your next investment!

blog.1000bulbs.com

"If the motor power factor is 100 (1), which is impossible, the utility would have to supply just 3.24 amps (746 watts) for the motor to run at full load. At a more realistic power factor of 75 (0.75), the utility would have to supply 4.32 amps (994 watts)."

A Different Approach to Understanding Power Factor (First of Three Parts)

Power factor (PF) is an important component of an alternating current (AC) circuit, but understanding its actual effect can be difficult. Why is PF mysterious to many of us? It has to do with the way it is explained. PF is often defined as the ratio of the real load power to the apparent power...

www.pumpsandsystems.com

I'm not sure, but I think induction motor power factor could be changed with capacitors.
LED bulbs, some are reported to be better.
PCs and other SMPS can be PF corrected, rather than simply diode/capacitor front end.
So you may be able to spend money to use more of your power. Or spend money to make more power.

 

[SignatureSolarJames]

I want to do a throughput efficiency showdown and check a lot of inverters at once