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

albyota

thats OK, The Inverter will use a small amount of power over night so that probably makes sense.

http://www.theowl.com/index.php?page=using-owl-with-solar-power

They say....

OWL Electricity Monitor will add the low level electricity consumed by the inverter ie night time, this consumption may be exaggerated because of the low power levels).

don0301

albyota wrote: »

thats OK, The Inverter will use a small amount of power over night so that probably makes sense.

http://www.theowl.com/index.php?page=using-owl-with-solar-power

They say....

OWL Electricity Monitor will add the low level electricity consumed by the inverter ie night time, this consumption may be exaggerated because of the low power levels).

the inverter uses 0.23W in "night" mode according to the destruction manual.

yeah, i just added some maths to my previous post to explain my fag packet maths.

Dave_Fowler

If you watch the OWL meter, you will see that the minimum step in reading is 17W - (or 16W) - It is not a continuously variable 1W at a time. So if you find your reading is a steady 113W it just means it is not varying by more than +/- 17W.

From your reading of 113W I suspect your Voltage is set to 230V. My supply voltage is 240V and this translates 113W to a reading of 117W - which is what I get shortly after the panels start to generate. My 'zero' generation reading is 64W.

Dave F

don0301

Dave_Fowler wrote: »

If you watch the OWL meter, you will see that the minimum step in reading is 17W - (or 16W) - It is not a continuously variable 1W at a time. So if you find your reading is a steady 113W it just means it is not varying by more than +/- 17W.

From your reading of 113W I suspect your Voltage is set to 230V. My supply voltage is 240V and this translates 113W to a reading of 117W - which is what I get shortly after the panels start to generate. My 'zero' generation reading is 64W.

Dave F

its not actually "reading" the equivalent current for 113W, its an erroneous reading is my understanding.

its just pants at low current readings

i guess thats why its called a monitor, not a meter

KevinG

zeupater wrote: »

Hi

Is there a difference between the OWL displayed power and the display on the Fronius ? .... also, have you checked the voltage setting on the OWL ?.

The OWL is only capable of measuring Current, it then multiplies this by an internal Voltage variable to calculate the Power ....

HTH
Z

I set the voltage on mine to 250 for this reason, from its default of 230. Gives a higher power reading and more likely to be accurate as I understand it.

KevinG

Dave_Fowler wrote: »

From your reading of 113W I suspect your Voltage is set to 230V. My supply voltage is 240V and this translates 113W to a reading of 117W - which is what I get shortly after the panels start to generate. My 'zero' generation reading is 64W.

On my OWL, the "zero" (i.e. inverter only) reading at 230V was 64W, at 240V, 67W and at 250W it's 70W, so they differ slightly.

zeupater

KevinG wrote: »

I set the voltage on mine to 250 for this reason, from its default of 230. Gives a higher power reading and more likely to be accurate as I understand it.

Hi

My point exactly .... it's Saturday evening and the mains is registering 243.3V here at the moment ... on a weekday afternoon it's a little higher .... it all just adds to the inaccuracy if the voltage parameter is incorrect for the location ....

Our OWL monitors household load, when it's zero the monitor reads zero, however, it doesn't provide readings below 50W, but above this it's pretty accurate.

A consideration worth note is that our system is based on a second dedicated consumer unit for the pv system with Henley blocks to split the feed from the import meter with the sensor being clipped between the Henley block and the main consumer unit ..... if the split sensor for the OWL rests on the Henley block it reads inaccurately but moving the sensor away from the solid block corrects this, I take it that the solid mass of the metal in the block has an effect on the induction field for the sensor .... it could be possible that a sensor installed within a consumer unit could be picking up a low-level field from other cables or the busbar, but this all depends on where the clip has been fitted ....

HTH
Z

don0301

KevinG wrote: »

I set the voltage on mine to 250 for this reason, from its default of 230. Gives a higher power reading and more likely to be accurate as I understand it.

The owl monitor doesnt take into account power factor (the phase difference) as i understand it, read that somewhere, possibly on here.

anyway, the points mute, my monitor is accurate to approx 5%, which is what it says on the tin. its accurate enough to be useful.
but sadly not accurate enough for very accurate data collection/comparison.

I suppose i could ramp up the voltage setting on it like you or Z to make my readings even more impressive (and less accurate)

Martyn1981

Mentioned this before, and it might not suit many, but my Optismart that works off the red flashes on my TGM is 100% accurate (well, it's a 100% copy of the TGM so it's as accurate as the TGM).

One tiny gripe is that it updates with each flash (or gap between) so at lower revs it updates slowly, and vice versa.

Also noticed that my TGM is 1% more than my inverters. Not complaining, better than the other way around. Most inverters (from what I've heard) have a small eror factor, and they caveat this in the manuals.

M.

zeupater

don0301 wrote: »

The owl monitor doesnt take into account power factor (the phase difference) as i understand it, read that somewhere, possibly on here.

anyway, the points mute, my monitor is accurate to approx 5%, which is what it says on the tin. its accurate enough to be useful.
but sadly not accurate enough for very accurate data collection/comparison.

I suppose i could ramp up the voltage setting on it like you or Z to make my readings even more impressive (and less accurate)

Hi

For accurate data collection does your Fronius have a USB port ? (http://www.fronius.com/cps/rde/xchg/SID-612DBFB6-8EABE265/fronius_international/hs.xsl/83_19090_ENG_HTML.htm#Datentransfer) ... if it does then I believe you can collect data and analyse it yourself using free Fronius software or directly within a spreadsheet .... I don't have a Fronius so maybe someone else could confirm this and help if you decide to take this route ...

The idea of checking the voltage parameter on the OWL is to set the correct voltage, not to make your readings look more impressive .... we use ours to monitor spot usage, not generation, so it makes absolutely no difference to what we believe the system has produced.

HTH
Z