So now I have a solar PV system how do I make the most of it???

sly_dog_jonah

Month        Em         Actual     % difference
Oct*          61           79.9       +31%
Nov           120          136.6     +12%
Dec           78.6         95.4       +23%
Jan#          103          131.3     +27%

*Installed with 10 days of month left so Em is pro-rata'd
Em = PVGIS monthly generation estimate
# 2 days left (but it's snowing today!) Now updated with full January figures

Our system for the stattos:

3.7kWp panels (20x 185W Enfinity-185M5) on two strings (top row and bottom row)
Enfinity 3680-TL inverter
Roof angle: 42 degrees
Orientation: SE (-36degrees)
Post code: BS40
No shading except on bottom row as sun rises above next door in the morning (just out of shade about 0840 late Jan).

Overall we're running at 22% above Classic-PVGIS estimate.

zeupater

Martyn1981 wrote: »

Z, please stop going down this route.

My understanding is that you think the voltage of the Owl should be set to match PV (around 250+V) to 'better' match the 'real' output.

Whereas Don (with the Owl set at 230V) is already getting a small over-reading (perhaps 5%), so increasing the voltage setting will further increase the error and make use of the monitor, solely for real time decisions, less useful.

The fact that Don doesn't agree with you, does not mean you have to keep calling him a Troll. He hasn't called you a Troll because you don't agree with him, has he?

Others have commented on the error margin that the Owl has (and I believe all clamp type devices have). And Don has to set his up best to work within those tolerances.

If you keep down this road, you're going to begin to sound like Graham soon. Anyone who disagrees with him is a PV lobbyist, or an anti nuke green, or an out of work PV installer. Some of us simply have a different opinion, is this not allowed? It hardly makes us spammers or Trolls.

As the great American philosopher J. Nicholson once said; "Can't we all just get along?"

Mart.

Hi M

If you check all of the posts made by Don you will find that the 'overreading' error described is creep in the differential between the TGM and the cumulative metering of Energy on the OWL monitor, not the Power reading, therefore I cannot understand why you have posted .... "is already getting a small over-reading (perhaps 5%), so increasing the voltage setting will further increase the error and make use of the monitor, solely for real time decisions, less useful." ... the actual differential metered (post #1102) is not 5%, it's 40%(420/300) over 53 days before applying the logic to substantiate a 6% inaccuracy.

I really do follow the logic which is being utilised in the post which the accuracy is being attempted to be substantiated, but the logic utilised is flawed on so many fronts that it cannot be taken seriously .... for example, is the sensor measured baseload only there when it's not daylight and how would you know?, so could the assumption that "13 hours "nighttime" each day, thats 0.113kW*13*53=78kWh" just as easily be 0.113kW*24*53=144kWh at 230v, and would this not likely be ~150kWh at 240V ? ..... now taking the OWL metered 420 and taking 144kWh off would the result not be 276kWh? and would this not suggest that the Power reading was 8% low (276/300) ... and would adding that 8% to the set 230V not result in a theoretical average real voltage of ~248V, which seems to be pretty close to the ~247V posted in #1124 ... an error of 248/247, so within 1%.

My logic is that if the voltage was to be set to the most appropriate setting on the OWL then at least the spot reading of the power being generated would be as accurate as possible and the unit could be used as a monitor, which is what it designed to be .... This could easily be done and checked against the voltage as Don has metered the mains voltage and posted the results .... As previously posed, the inaccuracy seen on the cumulative energy display is likely to be the result of the location of the sensor effecting the field which induces a current within the sensor ... I have replicated conditions where this can be seen within my own system, therefore I know that these conditions can and do exist .....

The question regarding trolling is simply related to the repeated abrasive and sometimes bordering on abusive posting which is utilised linked to the repeated unwillingness to take very sound alternative logic into consideration .... perhaps you could review all of the posts and formulate an alternative view as to why such an inaccuracy exists in this situation, however, I do believe that qualified individuals on other fora would likely apply the same alternative logic ...

HTH
Z

Martyn1981

Z, maybe I shouldn't assume, but there are three factors I considered relevant regarding Don's over-reading of 113w

Firstly, his simple maths, of deducting only non generating hours, appeared to close the gap significantly between his Owl and TGM.

Secondly, my ENVi (and ENViR) model did a similar thing, of over-reading at 'low revs', yet seemed to be pretty accurate when heavy loads were running.

Thirdly, Don's posted Owl specs, and others comments seemed to suggest again that the error factors are greater at low revs, so it seems fair to discount them at high revs.

I guess we'll never get a definite answer on why and what the Owl does as it's not a precision tool (in this context). My concern was that having locked horns with Don, you twice took the opportunity to call him a troll, which I thought was a little unfair.

Hopefully, this is all water under the (troll) bridge now.

Thanks.

Mart.

Martyn1981

Still snowing here, only generating about 30 to 50 watts all day. Oh well.

Is anyone else getting snow?

M.

Yut_Man

Snow blimey. Im in manchester lovely clear sky and not a trace of snow for few weeks. Its 3.30pm and 1.5KWatt being generated. Only had system few months so cant wait to see what the summer does.

zeupater

Martyn1981 wrote: »

Z, maybe I shouldn't assume, but there are three factors I considered relevant regarding Don's over-reading of 113w

Firstly, his simple maths, of deducting only non generating hours, appeared to close the gap significantly between his Owl and TGM.

Secondly, my ENVi (and ENViR) model did a similar thing, of over-reading at 'low revs', yet seemed to be pretty accurate when heavy loads were running.

Thirdly, Don's posted Owl specs, and others comments seemed to suggest again that the error factors are greater at low revs, so it seems fair to discount them at high revs.

I guess we'll never get a definite answer on why and what the Owl does as it's not a precision tool (in this context). My concern was that having locked horns with Don, you twice took the opportunity to call him a troll, which I thought was a little unfair.

Hopefully, this is all water under the (troll) bridge now.

Thanks.

Mart.

Hi

I believe that below are the occasions which you referenced .... please review them within the context in which they were made at you leisure, I'm pretty sure that it would be possible to find abrasive & abusive posts to which they refer along the way. If someome posts in German would it be inconceiveable that they would be German ?, if they post in French would a Frenchman not be considered ?, so continual posting of abrasive & abusive comments with obvious intent to provoke reaction would be considered as being 'normal' .... ?

Regarding the 'simple' maths, is it inconceivable that the calculation is flawed because the logic itself is flawed, my own logic does not even seem to be considered as being a plausible alternative, even though I have replicated the situation as described .....

Regarding the OWL specs and error factors .... It was me who posted them, I have an OWL. What must be taken into consideration is that part of the inaccuracy is the voltage banding on the OWL .... you can only pre-set a voltage in 10V steps within the selectable range, however voltage is infinately variable within the same range, so there's an inbuilt potential error of up to ~2% (5V over 240V) just on the average supply voltage against the OWL banding, let alone the variability of Grid supply during the day .... that's the main reason why the manufacturers have tolerances ....

Information & recommendation have been provided, it's pretty simple to measure the mains voltage at a location/time, it's pretty simple to compare the OWL indicated power to the Inverter displayed power in order to gauge accuracy, and it's pretty simple to change the voltage setting on the OWL if deemed necessary ... all of these error-solving options have been sidelined and dismissed, seemingly to defend the logic behing some simple arithmatic, which many seem to believe is flawed, but without the recommended testing, how is anyone to help .....

The inverter's consumption of power overnight at a very poor power factor could be the root cause, it's been touched upon, but it would/should only really be significant if concentrating on the Energy (Power delivered or consumed over time) metered by the OWL (in kWh) and not the Power monitored by the OWL (in kW), but accuracy and tolerances based Energy is concentrated upon, even though the manufacturer published no such data, they publish Power and the reasoning for this has been described before ....

I just find the unwillingness to take things on-board and help onesself and ample willingness to invoke and provoke reaction interesting, as I do a move from a position of being a self declared " neewbie but interested to understand and maximise the system" a little over a month ago to posting in an extremely abrasive way just a few weeks and a couple of dozen posts later ..... what I also find interesting is that every time someone withdraws from the debate there is a deliberate attempt to goad a reaction (there are ample examples) in order to continue what seems to be a deliberate 'policy' of disruption .....

HTH
Z


.......................

zeupater wrote: »

Hi mickyduck (/ All)

Sorry if my posts in particular are coming across that way .... I have been attempting to explain what a split-ring monitor does and what the limitations are, as I believe that this is of use to others who would expect to measure Energy production or usage over time ... however, as my 'trollometer' has been flashing red and ringing loud for some time now I'll accept that it's probably correct and stop giving another member the usual courteous 'benefit of doubt' ....

Z

zeupater wrote: »

Hi

As the monitor measures current and displays power, the calculation would simply be wrong, and I really think that you know it, so there's no need to even consider the maths, just the logic Watts=VoltsxAmps, excluding power factor correction - but as the OWL cannot measure the power factor that additional element is irrelevant anyway ....

From what I can see, most join a community such as this to ask for assistance, or to provide assistance, or simply to learn ... on the other hand the are some who join to promote product (spam) or to simply agitate for pleasure (troll).

I, along with others, have attempted to help and instead of taking ideas aboard for consideration there is simply abusive retort which is consistant with one who is serial trolling. If you would like assistance in solving the issues you describe all you need to do is re-read previous posts and understand what they are actually saying .... not being open to this approach simply reinforces a very stereotypical profile.

HTH
Z

Brian99_2

We've had a few impressive numbers for recent kWh generated !!

Maybe they deserve a dedicated thread ?

I suggest we compare our January UNITS divided by kWp

This means a more level playing field (evens out the size of system), and will show MAINLY the effect of local weather; and also the effect of roof angle/orientation.

Will be interesting to see how "far-flung" places compare with the Sunny South

Martyn1981

Yut_Man wrote: »

Snow blimey. Im in manchester lovely clear sky and not a trace of snow for few weeks. Its 3.30pm and 1.5KWatt being generated. Only had system few months so cant wait to see what the summer does.

Hiya mate. Sorry to be nosey, but gotta ask the obvious question, generating 1.5kW at 3.30pm, do you have a west system?

Any specs would be interesting, I'm a number freak, sorry.

Inverters spent all day starting up, and shutting down, but no snow settled.

I got a lucky today, only generated 0.25 but that clicked my TGM over another 1, so only 1 unit short of estimated for Jan. Yeah, I know it's all nonsense, but it's kinda fun nonsense!

Mart.

sly_dog_jonah

Brian99 wrote: »

We've had a few impressive numbers for recent kWh generated !!

But they need to be on a DEDICATED thread.

I suggest we compare our January UNITS divided by kWp

This means a more level playing field (evens out the size of system), and will show MAINLY the effect of local weather; and also the effect of roof angle/orientation.

Will be interesting to see how "far-flung" places compare with the Sunny South, on a dedicated thread

Maybe I'll start one tomorrow night.

Posting a link to your system's pvoutput.org page might be quicker. This can 'do the maths' for you as well as encapsulate system specifications. It's very easy to create and update from whatever means you use to record your generation. I import the CSV output from our SoloPV monitor:

http://www.pvoutput.org/list.jsp?id=5499&sid=4374

Edit: Sun slowly burning off the haze in cider country today, and already generated twice the kWh we made yesterday in the sleet :-) Forecast looks good so we'll hopefully generate over 5kWh today to beat our Jan PVGIS estimate by 25%.

KevinG

When people talk about "PVGIS" estimate, are they referring to "Classic PGVIS" or "Climate-SAF PVGIS", which is rather higher? (See http://re.jrc.ec.europa.eu/pvgis/apps4/databasehelp_en.html)
I'm going to beat both for January so I'm not too bothered, but I did wonder.