Solar PV Performance Thread - Post your monthly output

Interesting project that. I started to work the math out on it a few months ago. The problem John is that the Met Eireann numbers which are given are for a m^2 which is perpendicular to the sun. i.e. the suns rays are shining directly on that sq meter throughout the day. They may have a tracking platform, not sure.

For us of course, out panels are mounted to roofs with fixed pitches and will only briefly be perpendicular to the sun (if at all) during the day. So your square panel, will appear from the perspective of the sun to be a parallegram, with varying "apparent" surface area as the day progresses.

It can be worked out of course by integrating the area over time during the day, but it started to get more work than I wanted. There are some sites out there such as pvsol, which do the math for you.

That said your 12% doesn't sound too off though.

October Stats

6.2kWp (2.8 south/3.4 west), 20kWh battery, Zappi & Eddi – Donegal

Generation – 251.7kWh (just 3kWh less than October 2020)

Export – 19.9kWh (an increase oddly enough, due to battery issues)

Import – 461.4kWh (up about 16%)

Best day - 2nd, 15kWh

Worst day - 14th, 2kWh

Had to repair bits of my BMS and then rebalanced the cells so the battery has been out of use for the last week or so, resulting in high export.

Yes, I'd be fairly aware of that, what I would be interested in is the power output at any give time of the day for a few different radiation levels, for example if the radiation was 1000watts/M2 at say 1300 hrs one day and the next day, at exactly the same time was 500watts/M2 is the output fairly proportionate with solar PV.

What surprises me a bit with mine (solar thermal) is how consistent the output is year after year, I have got 930/1025 kwht/annum for the last 10 years from nominally 4M2 (3.76) panels which gives a efficiency of ~ 25/27%.

Is 5M2/kwp a reasonable figure to use for the PV panel area?.

Yeah in theory the HW is separate to the central heating. I tuned off the water heating aspect so as far as I can the days when the heating is not on all the HW is from the Eddi

central heating only just turned on agin this week so that will heat the water also when it’s running.

we have never been heavy electric users so thought this was normal - have I missed something. Only two of us in the house

It is defiantly heating the water but I will give that a try thanks. I am glad i posted the stats :D

Still getting to grips with the monitoring app (Solarman), doesn't seem to give a monthly figure for consumption, grid export etc just production. I can see graphs for the above but not a figure.

6.2kWp system, SE aspect.

October: 330.78kWh.

Best day (2nd) 23.35kWh

Worst day (7th) 1.55kWh

September was 392kWh, August 578kWh and July (first full month after install) was 745kWh. 2.1MWh produced since installation on June 28th.

Is it solis home app on android? That's the old one I use but it looks different

2.5 kwp south facing Galway.

Total for month was 174.8 kwh.

Best Day 5/10 13.8kwh

Worst day 7/10 .8kwh.

Thanks for the steer. I killed the boiler just to see how much demand I could send to the Eddi. I need to play around with the heating because it must have been still running sometimes to keep the water temp up. the cylinder is big and well insulated but I’d still prefer to use the excess solar myself.

2.52kWp south facing, Dublin city, installed Dec 12th 2020.

December total 58.4kWh

January total 82.6kWh

February total 148.3kWh

March total 222.8kWh

April total 327.2kWh

May total 345.6kWh

June total 341.1kWh

July total 334.2kWh

August total 254.6kWh

September total 214.9kWh

October total 192.4 kWh

Highest - October 1st (12.5kWh)

Lowest - October 13th (1.4kWh)

Highest Ever - July 19th (16.6kWh)

October Stats

6.4kWp (4.5 SSE, 1.9 WSW), 4.8kWh battery, Eddi, dumb electric car charger – Tipperary

 Generation – 320 kWh
 Export     – 14 kWh
 Divert     – 50 kWh
 Import     – 281 kWh

 Best day   - 1st, 22 kWh
 Worst day  - 27th, 0.6 kWh

Totals so far:

Month    |Generate (KWh)|Export (KWh) |Divert (KWh) |Import (KWh)
---------+--------------+-------------+-------------+------------
November |      163     |      --     |      --     |     443
December |      117     |       1     |      22     |     552
January  |      163     |       2     |      29     |     709
February |      213     |      10     |      47     |     496
March    |      436     |      26     |     119     |     384
April    |      705     |      54     |     219     |     207
May      |      734     |      63     |     223     |     141
June     |      722     |      54     |     230     |     104
July     |      720     |     177     |     220     |     111
August   |      613     |     127     |     184     |      58
September|      380     |      39     |      94     |     201  
October  |      320     |      14     |      50     |     281  
---------+--------------+-------------+-------------+------------
Total    |     5307     |     566     |    1437     |    4287 

I've just completed my first year of solar - overall pretty happy with it. It slightly irks me that my 4.8 KWh battery is not enough to make me 100% self sufficient in the summer, and I end up diverting during the day and buying back 3-4 kwh during the summer nights. Though a larger battery is also probably not worth the cost (and the DIY, while impressive, scares me a bit too much to take it on!). Fingers crossed batteries will get cheaper in the next few years.

Congrads man. I'm sure it's a nice feeling.

Should be able to keep your existing battery and drop in another 4.8kWh to run in parallel , no? Looking at your stats for the year, you have a lot of months where you could fill a 10kWh storage, giving up some hot water possibly.

Well I think I have a very good alignment, I don't have any shadow at all at any time of the day and its on an relatively elevated exposed site so I get the sun early and late in the evenings. The array is split into two (roughly half and half) one is directly facing south and the other is just turned about 15deg to the east so stretches out the evening. Also both of them are tilted 40deg

I am already at 69 kWh for the first 2.5 days this month💪 Just need to use as much of it as I can now

Cork 2.08 kW South facing.

141.8 generated