Wed, 17 Jun 2026 14:13:41 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=147396#Comment_147396 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=147396#Comment_147396 Wed, 30 May 2012 14:19:11 +0100 jms452
So using pvgis (thanks Damon) I calculated the clear sky irradiance of the two 45 degree inclination arrays 1.75kW SSE(-11) and 2.25kW WSW (-79) for May.

The pvgis fixed plane clear sky irradiance is multiplied by panel efficiency (15.4%) x panel area (1.6m2) x no of panels (16) x non-panel system efficiency (90%). The the two aspects summed for each time interval.

This only holds for a perfect cloud free days so I was rather chuffed when day 1 was the start of our mini heat wave!

The only fudge factor is the non-panel system efficiency (inverter + wires + panels getting hot + etc) which pvgis suggests as 86% but I got a better fit at 90%.

So it seems at a first (and arguably second) order pvgis is a very good predictor of clear sky irradiance and that my array(s) 'does what it said on the tin'.

Now it just 'weather' to investigate - I think I should hold off for a bit before making any impressive claims for annual yield based on the 5 days since install..]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=147398#Comment_147398 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=147398#Comment_147398 Wed, 30 May 2012 14:21:23 +0100 jms452 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=147401#Comment_147401 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=147401#Comment_147401 Wed, 30 May 2012 14:34:51 +0100 SteamyTea https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=147402#Comment_147402 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=147402#Comment_147402 Wed, 30 May 2012 14:40:32 +0100 SteamyTea https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=147433#Comment_147433 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=147433#Comment_147433 Wed, 30 May 2012 18:36:16 +0100 DamonHD
I get some very early morning shading even now from a tree a considerable distance to the north east of us.

Rgds

Damon]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=147454#Comment_147454 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=147454#Comment_147454 Wed, 30 May 2012 20:06:45 +0100 jms452
The dip on actual is partly due to a big tree about 50m East from us and partly due to a slight haze that morning - on subsequent mornings it moved up close to predicted at about 8:30.

In general very pleased both with the direct sunlight performance and the amount of power we generate even when its cloudy. i.e. in todays thunder storm we had ~100W as we do at the moment (wrote at 8:30pm -dusk approaching) !]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=147455#Comment_147455 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=147455#Comment_147455 Wed, 30 May 2012 20:10:58 +0100 SteamyTea Keep wanting to test this more to find out how much difference it makes over a year.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=178077#Comment_178077 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=178077#Comment_178077 Mon, 17 Jun 2013 21:56:59 +0100 jms452
Predicted (by the installers): 3152kwH
Actual: 3510kwH

]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=178090#Comment_178090 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=178090#Comment_178090 Tue, 18 Jun 2013 07:07:54 +0100 SteamyTea Do you have the split on the two strings/arrays?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=178109#Comment_178109 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=178109#Comment_178109 Tue, 18 Jun 2013 09:02:39 +0100 billt
Quoted SAP production for my system was 3026 kWhr P.A., PVGIS prediction was 3450 or 3710 depending on which model was chosen. Actual production is 7043 kWhr over 2 years, 3520 P.A., 16% more than the SAP estimate.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=178153#Comment_178153 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=178153#Comment_178153 Tue, 18 Jun 2013 18:34:39 +0100 jms452 Posted By: SteamyTeaDo you have the split on the two strings/arrays?

Yes using a 2 string independently MPPTed inverter (SMA 3600TL) one string for the 1.75kW SSE and the other for the 2.25kW WSW.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=178169#Comment_178169 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=178169#Comment_178169 Tue, 18 Jun 2013 22:13:48 +0100 SteamyTea https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=178189#Comment_178189 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=178189#Comment_178189 Wed, 19 Jun 2013 10:40:41 +0100 jms452 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=178192#Comment_178192 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=178192#Comment_178192 Wed, 19 Jun 2013 11:27:54 +0100 jamesingram "OptiTrac Global Peak is an extension of the proven OptiTrac yield optimization function.
OptiTrac Global Peak improves the yield of the PV plant for partially shadowed PV modules. Detailed
information on this topic is available in the technical information "Shade Management" in the
download area at www.SMA.de/en."]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=178333#Comment_178333 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=178333#Comment_178333 Fri, 21 Jun 2013 09:18:43 +0100 jms452 Posted By: jamesingramIs the SMA3600TL set on optitract global peak

Its the 3600TL-20 and the data sheet claims 'Shade management with OptiTrac Global Peak'.

Is this something that I can bluetooth into the inverter and check it is enabled?

I'll have a look but the installers seemed pretty clued up...]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=178334#Comment_178334 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=178334#Comment_178334 Fri, 21 Jun 2013 09:25:44 +0100 SteamyTea Posted By: jms452
Is this something that I can bluetooth into the inverter and check it is enabled?
Yes it is.
I seem to remember chatting to some about OptiTrack and he though that it took longer to 'sort itself out' and that could cost you some power generation.
Never got to check it out, so only third hand information.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=178343#Comment_178343 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9144&Focus=178343#Comment_178343 Fri, 21 Jun 2013 10:23:03 +0100 jamesingram Will be on settings list, , I think you'll need to log on as installer, default password is shown on log on screen
Click on my name for email, send one over and I'll send SMA pdf on multi function relay and optitract ( not a great deal of info in it though)]]>