Depending on the orientation of the roof, the panels provide shading to the roof tiles and hence the temperature rise within the loft under sun is sig nificantly less after the panels are fitted. In practice a ventilated loft is no great problem for an inverter.
Not so. The panels have to fit on the available space. So depending on what's available Kw wise depends on what you get. There might be shading and orientation issues too.
The rating of the panels is a notional thing, not often achived in practice. Probably never in the UK.
Whoosh? 3.64MW > 3949W
No. There are UK maps giving % of max output for various areas. Cloud is the enemy. Even a slight haze cuts back output by 10% Sometimes there are "rain shadow " issues.
Ideal is intense blue sky, cold wind and long days. Not often that happens in the UK
Sea nearby is good for reflected light.
South coast of England is best. West half of UK is worst. Roughly speaking
In message , harryagain writes
"Edge of cloud" effects can push the output up quite considerably too. I've occasionally seen up to 4.3 kW (transiently) from a nominally 4kW array, where under clear sky the output doesn't go above 3.9 kW. Just need a means of moving the clouds around now...
I know of some that exceed the quoted performance. Some panels are specified at +5 -0 % so they will generate what is stated when they are installed.
En el artículo , A snipped-for-privacy@anonymous.invalid escribió:
Convert the useless windfarms into giant fans?
:)
Per zacker lee. B-)
A lot depends on whether you're at the top of a hill or the bottom. You get more direct sun if the horizon is further away. ie the sun rises earlier and sets later.
Also the panels "see" more sky. Indirect diffuse light seems to make quite a difference.
I've seen some installations that must give a pretty shitty output.
In message , Mike Tomlinson writes
:-)
but then:
Oops! I got a bit carried away there, but what's three orders of magnitude between friends? Time to slink off and fall on my AVO probes in shame.
Having more time, I've looked at the detail, instead of relying on the overview. When Idc was 17.95 A, Vdc was 200.579 (which works out at 3600 Wdc) output power is recorded as 3456. W
I don't know exactly how the logging deals with variations within the 15 minute measuring period.
If you consider the daily sunlight curve, even neglecting weather conditions, it is soon clear that it doesn't run flat out very often. It is still a little ahead of calculations overall, and I am quite satisfied with performance.
It varies a little, but seems to average 225 Vdc with the current at around 2.3 Adc
Chris
Time to bring this one out again?
Chris
I bet this one is as shitty as they get https://www.google.co.uk/maps/@52.527436,-2.008339,3a,75y,27.72h,85.64t/data=!3m4!1e1!3m2!1sfCkgcAgLa9DPKZCnSKo4bA!2e0?hl=en
Yes, pretty shitty, that tree needs removing or trimming back. I know of a worse one though.
Its even worse when you notice the tree is due south of the panels.
There are plenty such installations - here is another
https://www.google.co.uk/maps/@51.638253,-1.83933,3a,37.5y,93.34t/data=!3m4!1e1!3m2!1sdbZANETUgrojWxTU1MBapA!2e0?hl=en
Yes another crap one. The one close to where I live has panels facing West AND shaded by a high hedge. Doubt if it gets 10% of it's rated capacity.
Thank you all for your individual contributions.... It has made interesting reading.
It seems to me that running plastic flexible conduit butween the loft to the garage, and again from the garage to the hall CU might be more sensible....
My question now is how easy is it to use a draw string to pull cable through 10 of conduit with three bends in it?
WHat diamter of conduit should I be looking at?
10?
Flexible conduit is intended for short runs either with complex bends or vibrating machinery. Due to the corrugations, it might work for 10".
There's no point in installing conduit, it is indended for mechanical protection, sometimes to make cable renewal easier. Just install the cable. Make sure there is sufficient length at the ends to make off the connections (ie not too short). This can be hard to assess for unknown equipment. Make sure you mark up the cable ends as to what they are. You might need armoured cable if it's likely to be damaged.
Or just make arrangements for easy access to the cable run. ie hand holes with covers, removable floor boards etc. and install the cable later.
En el artículo , Stephen escribió:
If you mean three 90 deg bends, pulling 6mm^2 cable, impossible. You'll have to pull it through the straight sections one at a time, threading the bend elbows on after each.
I pulled 30m of 4mm^2 cable through a buried 40mm drain pipe with one 90 deg bend, it was a nightmare.
You will find it easier if you obtain the cable as single cores, rather than T&E. And get some lubricating fluid - it's made especially for this purpose.
One solar installation I looked at recently had two single 25mm^2 cables from the bank of 4 solar panels to the inverter, a run of about 15-20m.
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