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K

kevhky

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Hi, first off im Kev, hello to everyone to the forum

Just two weeks ago had a pv system installed but im not reaching my peak as so i think my system is as follows

14 x REC 240w panels total 3.36kw
1 x Powerone aurora unu 3.6kw inverter
South facing
roof angle 30 degrees

over the previous two weeks we have had some particular good sunshine days (well only a couple) but my highest peak since install is only 2.77kw

on these particular sunshine days it was midday and the sun was directly shining straight at me roof

I though on days like this i should be achieving maximum peak of at least 3.3kw - 3.4kw

Any thoughts on this or am i expecting too much

Thanks in advance

Kev
 
F

FB.

  • Thread Starter Thread Starter
  • #2
Recently my panels have only been running at about three-quarters of their maximum potential (2.7kW being produced with 3.7kW of panels and the same 3.6kW inverter as you).

Hot weather drops the output.

There also hasn't been much of a breeze to cool the panels recently.

....and round here (edge of the East Anglia fenland) it continues to be quite misty at times due to the evaporation from still-wet ground (normally we don't get much rain - it's only fenland because it's at or below sea level).

The panels should get closer to peak capacity when it's cooler and breezier - spring and autumn.
Of course, in spring and autumn the days are shorter, so although the daily peak may be highest in spring and autumn, the total daily generation probably won't be.
 
S

sedgy34

  • Thread Starter Thread Starter
  • #3
That's seems reasonable the hotter it gets its performance is slightly lower
 
K

kevhky

  • Thread Starter Thread Starter
  • #4
Hot weather drops the outpu
I realised this but a psl of mine who lives pretty much 2 mins away had his installed the same time
he has a 3.9 system and same inverter as me 3.6 aurora and he is peaking at 3.6

He has 16 panels rather than my 14

To me it just dont add up

My system
3.36kw with 3.6 inverter facing south with no shade

Mates system
3.9kw with same 3.6 inverter facing east 6 panels east 10 panels west

Any thoughts

Kev
 
P

PengEF

  • Thread Starter Thread Starter
  • #5
Mine was fitted about same time as yours. We are probably in different parts of the country so direct comparisons are not going to help. However last Sunday I had the best day so far and generated 26.7kWh. Was made up put the peak was way down at 3.4kW for a 4kW system facing SSW with zero shade. Now yesterday with a lot of cloud and the odd sunny spell I got 18.2kWh but it peaked at 4.06kW. Last Sunday with wall to wall sunshine the panels just got too hot. Yesterday and today conditions were right to get very close to the peak output at times but rubbish for sustained generation. Swings and roundabouts. Yours does sound low but it's almost impossible to say if something is wrong on just 2 weeks generating I would think but I am no expert.
 
B

babba

  • Thread Starter Thread Starter
  • #6
Mine was fitted about same time as yours. We are probably in different parts of the country so direct comparisons are not going to help. However last Sunday I had the best day so far and generated 26.7kWh. Was made up put the peak was way down at 3.4kW for a 4kW system facing SSW with zero shade. Now yesterday with a lot of cloud and the odd sunny spell I got 18.2kWh but it peaked at 4.06kW. Last Sunday with wall to wall sunshine the panels just got too hot. Yesterday and today conditions were right to get very close to the peak output at times but rubbish for sustained generation. Swings and roundabouts. Yours does sound low but it's almost impossible to say if something is wrong on just 2 weeks generating I would think but I am no expert.
Its hard to believe the SPLIT system of the OP mate is peaking so high ?
 
B

babba

  • Thread Starter Thread Starter
  • #7
Why the 3.6 and not the 3.0 Powerone if you were looking for peak performance.
 
K

kevhky

  • Thread Starter Thread Starter
  • #8
Its hard to believe the SPLIT system of the OP mate is peaking so high ?
I agree but ive seen it for myself


Last Sunday was my highest 19.5kw generated that day
my mate generated 21kw

Its baffling how i have the south facing with no shade, yes i do have two less panels but i should surely be matching at least

My panels are REC 240w and his are Canadian 245w

Kev
 
K

kevhky

  • Thread Starter Thread Starter
  • #9
Mine was fitted about same time as yours. We are probably in different parts of the country so direct comparisons are not going to help. However last Sunday I had the best day so far and generated 26.7kWh. Was made up put the peak was way down at 3.4kW for a 4kW system facing SSW with zero shade. Now yesterday with a lot of cloud and the odd sunny spell I got 18.2kWh but it peaked at 4.06kW. Last Sunday with wall to wall sunshine the panels just got too hot. Yesterday and today conditions were right to get very close to the peak output at times but rubbish for sustained generation. Swings and roundabouts. Yours does sound low but it's almost impossible to say if something is wrong on just 2 weeks generating I would think but I am no expert.

Good stuff mate, obviously keeping a close eye like myself :0)

Like you say it is swings and roundabouts but i just want to see mine peak so i know all is working ok

Im from north east, UK


Kev
 
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K

kevhky

  • Thread Starter Thread Starter
  • #10
Why the 3.6 and not the 3.0 Powerone if you were looking for peak performance.
Well my panels are 3.36 so isnt that what i should peak at, im led to beleive thats the case

Kev
 

whinmoor

-
Arms
I would have been tempted to go for the 3.0 rather than 3.6 on this setup. Not much in it as you are caught between two stools but the lower rated inverter may be more efficient on cloudier days which are generally more common in this country. Maybe the 3.6 would be better down south and the 3.0 better up north.
 
K

kevhky

  • Thread Starter Thread Starter
  • #12
I would have been tempted to go for the 3.0 rather than 3.6 on this setup. Not much in it as you are caught between two stools but the lower rated inverter may be more efficient on cloudier days which are generally more common in this country. Maybe the 3.6 would be better down south and the 3.0 better up north.
I just went with what the company reccomended

The inverter has two strings but they only used one

Kev
 
F

FB.

  • Thread Starter Thread Starter
  • #13
I realised this but a psl of mine who lives pretty much 2 mins away had his installed the same time
he has a 3.9 system and same inverter as me 3.6 aurora and he is peaking at 3.6
He has 16 panels rather than my 14
To me it just dont add up
My system
3.36kw with 3.6 inverter facing south with no shade
Mates system
3.9kw with same 3.6 inverter facing east 6 panels east 10 panels west
Any thoughts
Kev

The numbers supplied by your neighbour are not accurate - or maybe he has premium-priced Sanyo/Panasonic panels which cope better with hot weather, or perhaps his roof is less steep than yours.

How is he measuring the power production from them - and have you seen the facts or is it just word of mouth?
Are you sure you're comparing yours and your neighbours systems at the same time on the same day?

It's also possible that maybe conditions are ideal, but that you still have scaffold up, or some kind of shading from telephone wires, trees etc which can knock the system output down by quite a lot.

An East/West split never has all the panels in perfect alignment with the sun, so is much less likely to reach full output at any one time than a South-facing. The benefits of East/West splits are a longer period of generation, but at a lower and more stable level than an array with a single facing.


I know someone with 4kW of panels split into back-to-back arrays of 2kW each and the Aurora inverter and it peaks around 3.5kW in good conditions.

On the other hand my 3.7kW system facing SouthEast peaks at 3.7kW in good conditions. But mine doesn't hold near peak output for as long period of time because my panels only have one "sweet spot" for teh sun, whereas a split system has two "sweet spots" but only one group of panels can be in the sweet spot at any one time.
 
I just went with what the company reccomended

The inverter has two strings but they only used one

Kev
Hi the most reliable way to check your output is to compare it with systems in your local area on PV Output org but bear in mind that all systems have many variables (direction of the panels, type of panel, type of inverter, length of cable runs to name a few). This site lets you graph similar systems in your area or anwhere in the UK against your system which will give you a baseline for your systems operation. Please note that it is nearly impossible to compare two similar systems even if they are on two houses 100 metres apart because of the many variables involved but an average baseline that can be compared against local systems is an invaluable tool for ongoing monitoring of the systems performance. If you look on PV ORG you will be surprised how variable similar systems are due to the above variables. My system is listed on PV ORG as Sunny Middlesbrough so in the NE like yourself and I compare it with a local system called Battersby Station which is slightly larger but gives me the same general generation graph but slightly lower therefore showing my system as being in good health.

Ken.
 
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K

kevhky

  • Thread Starter Thread Starter
  • #15
Hi Ken im on pvoutput currently giving live outputs
KevHky - SEAHAM July 2012



I know every system is and will be different its just i have the advantage of roof direction but not achieving peak


My roof angle 30degrees my mates roof is 45degrees


Neither of us have premium panels although mine are supposedly the better ones out of the two of us


Kev
 
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M

moggy1968

  • Thread Starter Thread Starter
  • #16
The power one has to be set up correctly by moving a jumper cable inside the inverter, without this the system will not perform at it's peak. I wouldn't have split this into 2 strings unless there was a specific need and would have also used a 3kW inverter, although, as above, the choice is marginal.
 
K

kevhky

  • Thread Starter Thread Starter
  • #17
The power one has to be set up correctly by moving a jumper cable inside the inverter, without this the system will not perform at it's peak. I wouldn't have split this into 2 strings unless there was a specific need and would have also used a 3kW inverter, although, as above, the choice is marginal.
Hi its not set up as 2 strings only using one string

Whats this jumper setting you mean, surely this should have been done on install

Kev
 
M

moggy1968

  • Thread Starter Thread Starter
  • #18
yes it should have been. If it hasn't been set up correctly the inverter will try and split the 1 string into 2, as I found on an install last year! I wouldn't normally use this inverter for a single string configuration but it was the only one of the good quality inverters I could get at the time. Once set up properly it was fine.
There are instructions in the instruction book on this but they are poorly translated so not that easy to follow. I seem to rmember you could tell from the display if it was splitting into 2 strings in the inverter.

Having said al that, we just set up a 3.1kW sytem with an SMA 3000HF. We finished around lunchtime weds and it was only outputting around 2.4kW, but it was over 30deg with no wind.
 
K

kevhky

  • Thread Starter Thread Starter
  • #20
The jumpers, red and black (supplied in plastic bag) need to be added and the dip switch set to par.
Thanks for that info matey

He left no jumpers but ill have some ilying around

Do these jumpers need to be in any sort of order or is it basically they are on or off
 
You really need to speak to the installer. He should have fitted them and set the dip switch, if he hasn't, get him to do so. You will void the inverter warranty if you fit anything other than the aurora jumpers.
 
K

kevhky

  • Thread Starter Thread Starter
  • #22
You really need to speak to the installer. He should have fitted them and set the dip switch, if he hasn't, get him to do so. You will void the inverter warranty if you fit anything other than the aurora jumpers.
When i get home (currently at work :() ill have a look see if the jumpers have been fitted (maybe they have already) if not ill get in touch with the installer

Just to clarify it is the Aurora uno 3.6 outd uk version we are talking about
And running this only on 1 string i should have red and black jumpers installed and dip switch set to par

Please confirm and ill look tonight

Thanks again
 
W

wstevew

  • Thread Starter Thread Starter
  • #24
FYI my east/west 3.84kWp is peaking at approx 2650w (5 minute averages) on the recent hot days without any clouds. Daily generation in the 21s probably would be a bit higher without late afternoon tree shading.
 
K

kevhky

  • Thread Starter Thread Starter
  • #26
Yes as your link shows.
Solarsavings, Moggy1968 - Had the front off and NO jumpers, so popped down me mates who had same inverter fitted but IS using two strings, grabbed his unused jumpers and have now fitted them onto mine

one thing i have noticed since doing it on the screen in no longer shows pin\line 2 as it used to

Cant understand why the installer never done this as like you say its clear enough in the manual


Kev
 
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M

moggy1968

  • Thread Starter Thread Starter
  • #27
glad you got it sorted, well done. adapt and overcome!!
 
K

kevhky

  • Thread Starter Thread Starter
  • #28
Hopefully we get a bit sun tomorrow so i can see if theres any improvement

Kev
 
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Y

yorkshiremike

  • Thread Starter Thread Starter
  • #29
It is quite acceptable to connect only a single string to one input/MPPT (IN1), provided the maximum DC current is less than the rated limit for the input (16-18 amps). If it is greater (for example the 'string' is actually an array of two or more strings paralleled together), then what the patch leads and jumper setting let you do is 'share' across both inputs, so that each handles half the 'string' current, but only one MPPT is active (ie you parallel IN1 and IN2 internally)

If you are only using the one input (IN1), then the recommendation is that the other input (IN2) is shorted with a patch lead internally, but this is to avoid issues with the inverters diagnostics on DC side insulation and shouldn't effect peak generation.
 
My 3.6 Out uk was setup with 2x 8 panel strings wired as a single array into the inveter with the jumpers fitted but the installer didn't set the switch to 'PAR'. For the first month my system was badly down on performance until I figured out the setting was wrong. When I changed to PAR the output instantly doubled as could be seen on the graph on the deskview unit.
 
Kev, you're not far from me and I just checked your system against my WSW 3.9kW system on Pvoutput.org (Southwood solar) and yours has generally been putting out more daily kWh than mine since the begining. I am happy that my system is performing well compared to other local systems so I'd say yours has been performing above expectations and that it was setup ok from the start. The low peaks are probably just caused by high altitude haze or panel temperature the same as affects the rest of us.
 
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K

kevhky

  • Thread Starter Thread Starter
  • #32
UPDATE

Since putting rhe jumpers in my system it is now performing properly

My highest peak today has been 3.55kw far above what i was peaking before

This should have been carried out by the installer, feel sorry for anyone else if the same installer has done the same to them (they probably dont even know)

Thanks to everyone for helping me fix this problem

Regards

Kev
my system here on PVoutput http://pvoutput.org/list.jsp?userid=11847
 
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F

FB.

  • Thread Starter Thread Starter
  • #33
UPDATE

Since putting rhe jumpers in my system it is now performing properly

My highest peak today has been 3.55kw far above what i was peaking before

This should have been carried out by the installer, feel sorry for anyone else if the same installer has done the same to them (they probably dont even know)

Thanks to everyone for helping me fix this problem

Regards

Kev
my system here on PVoutput KevHky - SEAHAM July 2012 3.360kW
With the cooler breezier days, my system has returned to peak output during the sunny spells in recent days.

From what I've seen of my panels on hot, calm, sunny days compared to hot breezy days, I reckon around half of the power loss on those calm days is attributable to the temperature coefficient of the panels, and half due to the still air around the panels.
So on a 3.6kW system up to 0.4kW losses due to heat and another 0.4kW losses due to lack of cooling breeze.
 

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