My evening demand is low. I cook on the woodburner and turn on the immersion either when the panels are producing in the day or when I go to bed. I fil a flask with water heated on the wood burner so the kettle isn’t on for very long in the morning.

So does your inverter have more than one MPP tracker, Sharkbait?

Looking over on the whirlpool.net forum (Australian and covers a lot of PV stuff) it seems the newer inverters are usually OK with two strings on a single MPPT but I’ve contacted the inverter importer to see if we’d be better off with a twin MPPT inverter.

It’ll be easy to tell from the daily production graph. If it’s the usual dome that resembles a normal distribution curve then the inverter is coping. More pointed and it’s not. Frankly I don’t see how it can work with an E/W installation without two trackers which is why I posted my original surprise that there is only one inverter.

I’ve had an email from the inverter importer saying that for our setup we would be better off with a twin MPPT inverter and though he has seen some single MPPT installations with the same E/W split as ours and they work well.
I don’t want to be one of these people so I’ve fired an email to the suppliers/installers requesting a different inverter.

It’ll be easy to tell from the daily production graph.

You can see our live data HERE

We’ll have to wait for a nice sunny day before we can make anything of the data. At present all it tells us is that the weather isn’t too good.

At present all it tells us is that the weather isn’t too good.

It’s got that right then!

ohnohesback
So please explain this to me. As the peak electricity deamnd is during the evening, when it is dark, how will solar PV help?

We have daylight until nearly 10pm in the summer. But in hours of darkness you’d have to be importing electricity from the grid. The PV will contribute to the householders electricity demand in daylight hours. Any electricity not used when produced will be exported to the grid, and the system owner will be paid for this by the householders utility provider.

Any electricity not used when produced will be exported to the grid, and the system owner will be paid for this by the householders utility provider.

Yep, a massive 3.xp/KWh exported to the grid 🙁 You’re much better off using as much of your home grown power yourself.
To that end I’m trying to educate Mrs SB to try and maximise the power we produce – i.e. run washing machine, dishwasher, etc during the daytime and not at night, try not to run energy hungry appliances at the same time, etc. This will have more of an effect in the summer when we will hopefully be producing more power than we are at the moment.

I thought the UK had a similar tarif system to France: you get paid more for you production than you pay for your consumption.

A solar hot water heater is your next purchase, Sharkbait. Your wife can run the washing machine when she wants then so long as it fills direct from the solar tank on the wash part of the cycle. It depends on the machine but 80% of the energy consumed is just to heat the water even on a 30°C wash. Madame has now learnt to change four valves and turn them back after 10 minutes. The financial payback is longer than PV though even if you DIY.

I would guess that with your system, you export all of it to the grid. There is then a calculation done of energy generated against energy consumed and the money relating to the balance is sorted out ie what you generated minus what you consumed. You don’t consume your ‘own’ electricity.

Get everything on timers and run it during the day. They are doing this to modify your behaviour and get you consuming away from the 7am and 7pm peaks they want to flatten.

i have a couple of PV questions.. if the thing pays for itself in 20+ years, thats great news.. what other electrical products do you have that are 20 years old.. which of those is sited permanatly on your roof..

i can think of only 1 the tv aerial/ dish and i suspect few if any are 20 years old.. does anyone have a sky dish from circa 1991.. we did but it corroded to nowt at about 15 years..

Real life long term solar panel information:

http://info.cat.org.uk/questions/pv/life-expectancy-solar-PV-panels

They should last.

I would guess that with your system, you export all of it to the grid.

Was that aimed at me TT? If so, the output from the inverter goes straight into our consumer unit where we use it, anything we don’t use goes out to the grid – even though we get paid for 50% of all the power we produce.
In reality, at this time of year, we use everything as I work from home and have two servers running 24/7. In the summer we should export a bit.

I still have my 91 sat dish installed and working, picking up French and German analogue signals; it’ll go in March whe the Germans turn off the analogue signal. My Jan 92 Peugeot has been parked outside for very nearly 20 years and still fires first time every time (though the top layer of paint has peeled of due to the sun).

Solar World panels are guaranteed to lose only 0.7% of their initial production per year for 25 years.

Solar World panels are guaranteed to lose only 0.7% of their initial production per year for 25 years.

Which is quite impressive really – so if a panels stops working they’ll give you another.
This plus the fact that there’s no moving parts and theres almost no/very little exposed steel in the brackets makes me think that they’ll be around in 25 years.
The inverter is another matter, but I think the prces of those will drop over time and they’re pretty simple to replace.