Would you do it again?

Martyn1981

rugbyleaguesmate wrote: »

OK Martin understand sorry for putting you in an awkward spot......

So if I choose one which is battery ready, which produces lots of kws but not more than 8.1kw?

Any particular panel make?

Solar edge se6000 the right invertor?

Sorry again

Ian

:rotfl: Isn't that the same question? Certainly gave me a chuckle.

Some thoughts. Re-cap for me, do you have any shading (try to think of the winter when the sun is lower, but also summer (now) when the sun is to the far east or west) if no shading, or very little, then SolarEdge might not be worth it, as it's a shading specialist, and you'll have extra components PO's (power optimisers) on your roof (albeit with exceptionally good warranties) where access may be needed.

But, there is a counter argument, as the warranty on the inverter is 12yrs, and I think you can extend to 20yrs for small beer. You also get live monitoring, and even without shading, the system maximises every individual panels performance, which could be 5%, or £20-£25pa in earnings.

Double/triple check that the SE6000 is suitable for the extra input. I know the spec sheet seems to confirm this, but I really don't know if there are specific preferences for a SE setup as the technology is a little different to a normal string inverter PV system.

Panels - don't get too worried about the panels. We all spent time trying to figure this out, but it's next to impossible. In 20 years we'll know which are the best, but too late by then. In general, they seem to do what they say, so perhaps stick with your plan of biggest system, so go for as many Wp's as possible, but do take cost into account, no point having a 285Wp system if each panel costs £20 more than a 280Wp.

The battery issue is hard, I genuinely don't know. You always have the fall back of an AC retrofit, so no need to panic, but the logic of an integrated DC system is hard to deny.

If it was me, I'd probably want battery ready, but are you able to find out how flexible these are, can you add any battery pack, as whilst we/the media tend to talk about Tesla PowerWalls, there are many other systems out there.

Is there any cost of being battery ready?

Trying to think what else to add ....... don't get stressed, if the annual income to cost ratio is acceptable to you, then don't stress too much. PV is shockingly boring on average, you will get the occasional rogue month, but expect gen roughly in line with PVGIS estimates.

Haven't really answered anything, just talked around the issues, perhaps I can cancel the bargepole order!

Mart.

rugbyleaguesmate

Martin thank you........and sorry.........I spent an hour on the telephone with the supplier armed with the information gained from here...very happy with my decision and have ordered 24 Ja solar 280w with solar edge 6000 invertor and a display unit. Happy with warranty and monitoring ability.

We don't have any shading but everywhere I research is very positive about Solar edge technology.

Haven't quite decided on a battery yet.......

Thanks again ian

tunnel

rugbyleaguesmate wrote: »

Martin thank you........and sorry.........I spent an hour on the telephone with the supplier armed with the information gained from here...very happy with my decision and have ordered 24 Ja solar 280w with solar edge 6000 invertor and a display unit. Happy with warranty and monitoring ability.

We don't have any shading but everywhere I research is very positive about Solar edge technology.

Haven't quite decided on a battery yet.......

Thanks again ian

No 2 for me but I'm biased to solar edge. Would have replied earlier but in a land where the sun always shines:cool:

rugbyleaguesmate

Ok install date set for 21st/22nd of Sept. Now to do my research on how to make the absolute best use of it.....

michaels

Suppose my panels cost 4850 and they returned 766 (FIT plus own use) in year 1 how much profit do I make over 20 years in current pounds assuming the funds spent on the panels would otherwise have earned 1% in real terms and the annual return increases with inflation?

pinnks

Key to making the most of your PV is to change from living in "parallel" to living in "series", i.e. don't just turn everything on at the same time (cooker, kettle, microwave etc) but time their use so that only one is on at a time if possible. That way you'll maximise your own consumption and minimise your import.

Also learn when your system produces the most kW - probably from about 10am to 4pm depending on location etc - and use electricity-hungry devices during that period (in series of course).

And finally for now, invest another £10 or so in one of those plug-in devices that tell you how much a device is consuming so that you know where your power is being used in the house. Not only will this help you work out when to use what but it will also make you generally more energy conscious - and if it pans out for you like it did for me you will find that some things you have always left plugged in are consuming significant amounts of electricity doing absolutely nothing. For instance, my extension lead with earth leakage detection was sucking 2W permanently just plugged in in the garage and my coffee machine about the same just sitting there plugged in. That's 4W, 24 hours a day, 365 days a year - 35kWh per year. My TV aerial amps and network switch (neither of which are needed for 99% of the time) consume about 20W, or 175kWh a year - and the list is likely to go on.

rugbyleaguesmate

24 panels fitted electrics and commissioning tomorrow............

Martyn1981

michaels wrote: »

Suppose my panels cost 4850 and they returned 766 (FIT plus own use) in year 1 how much profit do I make over 20 years in current pounds assuming the funds spent on the panels would otherwise have earned 1% in real terms and the annual return increases with inflation?

Hiya michaels, missed this completely.

I've had a quick play with Excell, and will explain my thoughts as you may not agree with my workings.

First a 20yr spreadsheet with £4,850 growing at a compounded 1% = £5,917.92. You can check this quickly if you have a calculator with a y to the power x button. Just type 1.01 then take it to the power 20 for 20yrs compounded. Multiply that figure by £4,850.

Next, I took the £766 income and increased it by 1.5%. I choose 1.5% as a slight cheat, it represents 2% inflation, less 0.5% panel degradation, but wrapped in a single calculation. This comes out at £1,016.44 in year 20, and a sum of £17,712.73 over the 20yrs. Again, you can check the £1,016.44 figure quickly by raising 1.015 to the power 19, multiplied by £766. [19 years as the money is available at the end of each year, not the beginning.]

Thirdly, I took the annual income (£766 through to £1,016) and 'invested' it, in the same 1% account. This came out at £18,388.63.

The including interest PV account matches the monies left in a bank account monies at the end of year 7. At that point in time the annual interest on the PV account will actually become greater than the annual interest on the monies left account.

You would need to include the cost of a replacement inverter, just in case, which will knock off around £800, and the interest on that £800 from the point it's used.

Also remember that the final monies are not in today's monies, since I've assumed a 2% inflation rate. In fact the 'monies left in the bank' at 1%, would actually devalue at 1% against a 2% inflation rate, so would be worth approx £4k in todays money.


For a year one profit figure you need to consider income and costs.

So we have a gross income of £766.

Costs will be:
Replacement inverter (£800/20yrs) = £40
Lost capital, dealt with as depreciation (£4,850/20yrs) = £242.50
Cost of capital, interest on capital (£4,850 @ 1%) = £48.50
Total costs = £331

Net profit in year 1 is £766 - £331 = £435

For subsequent years the income will be increasing by 1.5%, and there will also be the additional income from the interest on the monies being reinvested.

Hope this helps, but more importantly makes sense.

Mart.

Alan_Brown

I don't understand why you're both using a 1% return over the full 20 years? I can get a better return than that right now, and I don't think anyone believes that interest rates will remain low for decades?

Personally, I never expect to see a profit on my panels. I bought them because I wanted to reduce our family carbon footprint.

Martyn1981

Alan_Brown wrote: »

I don't understand why you're both using a 1% return over the full 20 years? I can get a better return than that right now, and I don't think anyone believes that interest rates will remain low for decades?

Personally, I never expect to see a profit on my panels. I bought them because I wanted to reduce our family carbon footprint.

Hiya. When PV cost £10k to £20k you would have had to compare it to higher interest investments, but now we are discussing figures around £5k, it's probably more correct to compare to lower interest, easier access accounts, even some ISA's which are now closer to 1%.

If I change the interest rate to 3%, then the capital in the bank increases from £5,917.92 to £8,759.64 an increase of approx £3k. The PV bank balance increases from £18,388.63 to £22,436.24, an increase of approx £4k. The PV balance overtakes the bank balance in yr8.

Mart.