Solar quotes for our house

[Shirley]

Ok, well I guess you are never too old to learn & I should lose points but we have to give the members with nothing to do an interest.

[BruceS]

I agree Shirley.
I always laugh when on a lot of forums someone will comment how quiet the forum is becoming.
When you look at how often that person posts you can see why!! (shakes head!)
No such thing as a bad post. (IMO)

[Mrcoolabah1au]

Yes shake my head regularly at the amount of thing I see

[Greynomad]

Ray, you missed the lack of an o in Shirley's sentence.

George

And one too many in her next post? Poor Shirley!!!

See? No-one's perfect.
That's why newspapers used to have sub-editors (now replaced by not-quite-as-sharp spellcheckers).

For example: A spellchecker couldn't correct "The thief took a picture of the wall." when what was meant was a picture was removed from the wall.
"Of" is a legally-constructed English word, and that's all they check. A sub-editor would look at the context as well.

[Newcastle George]

An update on the performance of the household solar system. The output in the last two days has been 30kWh/day. Not bad for early Spring. Since installation 17 July 1075kWh.

George

[Newcastle George]

It appears that the connection between the meter box and inverter, 13.5 metres, 4mm is too small, creating a difference of 4-6 volt difference between the two and thereby creating blips in the solar output which will cost us over time by way of reduced feed-in tariff.

Below is a graph of yesterday's output, blue and cloudless sky from dawn till dusk.

George

Click to enlarge

Solar output 27 Oct (Custom).PNG

[T1 Terry]

What voltage is each array, should be marked on the meter box and inverter and give a reading on the inverter as well. What panels and how many in each string?

T1 Terry

[Newcastle George]

Terry,

Panels are Suntech STP300S-20/Wfm (300W). Vmp 32.6. West facing PV1 10 panels, East facing PV2 12 panels. Inverter rated 5000W, voltage range 80-550Vdc/rated input 360V. Output current max 22.5 ac. Nothing marked on inverter or meter box. The maximum grid voltage shown on inverter yesterday was 256.8V. I had Ausgrid check the grid voltage at the meter box and was below 250 at approx 11am.

George

[T1 Terry]

Terry,

Panels are Suntech STP300S-20/Wfm (300W). Vmp 32.6. West facing PV1 10 panels, East facing PV2 12 panels. Inverter rated 5000W, voltage range 80-550Vdc/rated input 360V. Output current max 22.5 ac. Nothing marked on inverter or meter box. The maximum grid voltage shown on inverter yesterday was 256.8V. I had Ausgrid check the grid voltage at the meter box and was below 250 at approx 11am.

George

So, the east facing array would have an open circuit voltage of 480vdc (12 x 40vdc) and the west side array would have an open circuit voltage of 400vdc. At some stages through the day, the 5,000w inverter would be seeing 6600w of solar input, so would trim the input to limit the output to 5,000w, 22.5 amps x 265.8v = 5980.5w. The clipping you can see at around 13:05 is the inverter trimming to remain under the 5,000w, you can see the dip in both array graphs correspond with the dip in the output.
The reality is, even though it is a 6,600w solar array, there is a very small window that the inverter actually puts out 5,000w, the rest of the time the array in the sun isn't producing enough to reach maximum output.
The eastern array, even though the numbers add up to 3,600w, is only producing 3,000w at the very best and both times it was very short lived. You need close enough to 18 panels on the east facing array to get the 5,000w output by around 9am and hold that until around 3:30pm before it starts to taper off till virtually nothing by 5pm.

T1 Terry

[Newcastle George]

Terry,

Can you explain all the peaks and troughs in both the E and W prior to 11am? It was a completely cloudless day.

George