Tell me about your spreadsheets for solar panels!

We got solar panels last July and since then I have become a bit of a spreadsheet geek whilst getting on top of other financial areas of our life and now have spreadsheets for more things than you can shake a stick at.

I have a meter reading spreadsheet which has usage graphs etc and have added a couple of columns to work out how much money the solar panels are making daily/monthly.

I am thinking the next step is making a nice sheet like the companies trying to flog the panels give you that show you how much you make/break-even point etc.

Has anyone got a lot of sheets relating to their panels they can tell me about and feed my addiction? What sort of things do you track etc to do with your system?

Thanks:)
Jan 2013-£140,231.65
Jan 2014-£120,081.94

Replies

  • I don't have any spreadsheets. Not that this advances your thread much but more to let you know that you are not being ignored. :)
    Are you for real? - Glass Half Empty??
    :coffee:
  • jimjamesjimjames Forumite
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    Spreadsheets recording generation by month and year plus all FIT payments.

    Such a solar geek that I also load the daily data to a website each month to monitor how the long term comparisons are going.

    Comparison month by month

    http://solar-panels-review.321web.co.uk/monthly-pv-solar-panel-generation.php

    Comparing best days, monthly output year on year

    http://solar-panels-review.321web.co.uk/yearly-solar-panel-stats.php
    Remember the saying: if it looks too good to be true it almost certainly is.
  • EctophileEctophile Forumite
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    Spreadsheets? I just get a request every three months for a meter reading, I send them a reading, and the money appears in my bank account.

    I could carefully monitor my generation on a day-by-day basis, but
    • There's nothing I can do about the amount of electricity my panels generate. That's down to the weather.
    • I'd still end up with exactly the same amount of money in the bank.
    If it sticks, force it.
    If it breaks, well it wasn't working right anyway.
  • fothers365fothers365 Forumite
    269 Posts
    Wow Jimjames- that is highly organised! Does your equipment tell you all those details? Ours must be a lot more basic- as far as I am aware it just tells you current output, daily total, overall total. It doesn't tell any times or maximum output of the day etc.

    The tracking is just for interest really but at least if I check regularly and become familiar with the expected levels if any problem develops it might be spotted quickly.
    Jan 2013-£140,231.65
    Jan 2014-£120,081.94
  • jimjamesjimjames Forumite
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    The inverter is a Sunny Boy and you can get some software called Sunny Explorer that connects to it via Bluetooth to download all the data. I do that each month and it then shows 5 min average data for every day. My job is in IT so I'm familiar with moving data around and created some database tables to store it and then produce the tables.

    I know there is nothing I can do to increase the electricity produced but it is interesting to see how months compare to each other year on year. Also last month showed how much impact cold can have on generation, a cold day in APril generated more electricity than any day last year purely due to the panels being colder.
    Remember the saying: if it looks too good to be true it almost certainly is.
  • EricMearsEricMears Forumite
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    jimjames wrote: »
    . . . . . . a cold day in April generated more electricity than any day last year purely due to the panels being colder.

    If only it were that simple !

    Panel temperature is indeed important but seldom the main factor and never purely.

    Primary effects are of course panel efficiency - but there isn't a huge difference between the best and worst panels. It's also very important where the things are facing. Due South is of course best (unless you're an Australian surfer who didn't realise our audience is primarily UK based :D ) but E or W of S has some merit. Roof pitch is often overlooked (indeed, very few of our members include that in their autosig) - since the majority of British rooves have a slope of around 45 deg, they might expect a peak output in May or August; a very steep roof would be ideal in December (although day length will drop total generation then) and one as shallow as mine is never ideal - although certainly at it's best on Summer Solstice day.

    Then there's a whole world of cloud effects. No cloud at all in direct line of sight to Sun will give the best result but a bit of white fluffy cloud just off the direct line might boost that a bit. Hazy sky looks almost as good as no cloud to the casual observer but drops SP output drastically.

    Wind helps cool panels to boost output and a light shower might cool them enough to boost output when the cloud that caused it has blown past.

    But back to the main topic. I have several spreadsheets in progress. Sunny Explorer generates a new .csv file every day and for all practical purposes that is a new spreadsheet every day.

    I then have two main spreadsheets I keep up to date. Guess I could make them two pages of a single file but I've chosen to keep them separate.

    One is concerned only with generation and that starts with my pvgis 'targets' (bit of a misnomer really as they're simply the average of the last thirty years sunshine data mucked about to predict potential generation each month) and has monthly outputs entered and used to calculate FIT revenue and a comparison with the 'targets'.

    My other spreadsheet has monthly meter readings from import and export readings (and additional records on FIT claim days or requested import reading days) so that I can calculate costs of imported electricity and FIT revenue (again) in the same file.
    NE Derbyshire.
    4kWp S Facing 17.5deg slope (dormer roof).
    BEV : Nissan Leaf e+
  • jimjamesjimjames Forumite
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    EricMears wrote: »
    If only it were that simple !

    Panel temperature is indeed important but seldom the main factor and never purely.

    Very true. However other than cloud cover the other items aren't really relevant in the comparison for my panels as I'm comparing like with like. So orientation, my roof pitch and panels efficiency haven't changed (other than dropping as a year older) since last year so the real variable is the temperature/wind on a sunny day compared to a warmer day last year.
    Remember the saying: if it looks too good to be true it almost certainly is.
  • edited 5 June 2013 at 9:55PM
    EricMearsEricMears Forumite
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    edited 5 June 2013 at 9:55PM
    If you look back to the 'discussion' between Kernel & I around 6pm in the generation thread you'll see that he's noticed that he's suddenly moved from being just a little better than me to being just a little worse. We're at same latitude and less than 20 miles apart. Both of us think last few days (except today) were bright with little cloud but I'm convinced his little cloud was bigger than my little cloud.

    I'm still convinced cloud cover will be a huge (and virtually unmeasurable) variable.
    NE Derbyshire.
    4kWp S Facing 17.5deg slope (dormer roof).
    BEV : Nissan Leaf e+
  • edited 19 June 2013 at 9:09PM
    CavemanuCavemanu Forumite
    63 Posts
    edited 19 June 2013 at 9:09PM
    hi there I use PVoutput website.

    It was developed in Australia but used by 1000s of PV-ers all over the world, including lots of UK people.

    It is a free resource (but you can make a donation to the creator by paypal which I've done as it saved me tonnes of time and effort) and have been using it since 2011.

    You get graphs and you can compare different systems, slopes aspects, shading etc. You can add your data manually daily by doing a meter reading (which I do) or an automatic upload if you have the know how.

    www.pvoutput.org

    It is helpful, at least for the 1st year to get a feel for generation production and like you say, you can see if the numbers have changed! You can feed in the FIT rates etc and also add your consumption if you like.

    For the competitive or merely curious, you can also join teams by geography or solar panel type/inverter type etc. The community is quite friendly and have communicated with a few people to share knowledge and tips.

    Hope this helps you enjoy your new gadgets!
    best wishes
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