Solar Panel Guide Discussion

zeupater

Sirlaughalot wrote: »

... what`s the effect of continually running the inverter at it`s maximum performance in terms of inverter life as the guarantee is 5 years though additional insurance of £100 gets you 10 years ...

You must recognise that 4kWp of panels with a 4kW nameplate inverter will be generating 4kW for a total of only a few hours over a year if you're lucky !! .... the majority of total annual generation will be nowhere near stretching the inverter's capabilities and it will very rarely be producing over 90% (3600W) for an extended period, with decent production being somewhere around the 80%-85% (3200-3400W) mark.

It is possible to size the inverter below the peak capacity of the panels, in which case the inverter will be running at a higher loading percentage, however, doing this will certainly 'clip' some generation. The MPPT algorithm will simply draw as much DC power from the array as it needs to maximise AC provision within the hardware & software limits of the inverter, so as long as panels & inverter are appropriately matched there should be no 'wasted' investment.

S0larWorld panels are classified as 'plus sorted' and this seems to be what the installer is pushing. This simply means that as each panel is flash tested at the end of the production process they are placed in stacks depending on performance ... most manufacturers do this and only allocate a part-number after this process, ie they become 240W, 245W or 250W (etc ...) panels with the higher performance models being sold for a premium ... some manufacturers have a +/- tolerance on performance, others have a + only tolerance ... what you actually receive depends on luck, the panels could be minimum tolerance or anywhere above it within the allowable band for that particular model.

HTH
Z

zeupater

Sirlaughalot wrote: »

Has anyone heard of PV magazine and how can you get hold of it?

SL

Hi

https://www.solarpraxis.de/shop/shop-pvi/section/products_listing/pv-magazine/

.... however, it seems to be more of a trade publication than one aimed at consumers ... there's plenty of 'magazine' type resources available on-line which contain ample consumer information, including the one mentioned ....

HTH
Z

Sirlaughalot

zeupater wrote: »

You must recognise that 4kWp of panels with a 4kW nameplate inverter will be generating 4kW for a total of only a few hours over a year if you're lucky !! .... the majority of total annual generation will be nowhere near stretching the inverter's capabilities and it will very rarely be producing over 90% (3600W) for an extended period, with decent production being somewhere around the 80%-85% (3200-3400W) mark.

It is possible to size the inverter below the peak capacity of the panels, in which case the inverter will be running at a higher loading percentage, however, doing this will certainly 'clip' some generation. The MPPT algorithm will simply draw as much DC power from the array as it needs to maximise AC provision within the hardware & software limits of the inverter, so as long as panels & inverter are appropriately matched there should be no 'wasted' investment.

S0larWorld panels are classified as 'plus sorted' and this seems to be what the installer is pushing. This simply means that as each panel is flash tested at the end of the production process they are placed in stacks depending on performance ... most manufacturers do this and only allocate a part-number after this process, ie they become 240W, 245W or 250W (etc ...) panels with the higher performance models being sold for a premium ... some manufacturers have a +/- tolerance on performance, others have a + only tolerance ... what you actually receive depends on luck, the panels could be minimum tolerance or anywhere above it within the allowable band for that particular model.

HTH
Z

Thanks Z,

The installer quotes PV magazine as stating solarworld was awarded solar panel of the year in their annual awards.

SL

John_Pierpoint

Sirlaughalot wrote: »

Thanks Z,

The roof space issue regarding space is no longer a problem as the initial survey got the roof measurement incorrect, they quoted 7.0m x 5.0m should be 7.1m x 5.3m. Don`t know if this was a deliberate act(to stop me looking for a 16 panel system) or a genuine mistake but if i dont mind the effect of a portrait/landscape panel layout then the cost savings of perbright/solar world panerls against the the quality of sun world panel can`t be ignored.

SL

Don't forget that the ridge tile and probably the two "courses" of slates/tiles under it cannot be readily lifted to tuck the mounting brackets underneath, when screwing them to the common "jack" rafters.

The salesman who made some rudimentary calculations from ground level specified three rows of portrait. In the event I double checked his calculation and we compromised on top two rows of portrait and bottom row of landscape.

[Its a bungalow - I was prepared to take the ridge off and replace it BUT the installer realised that in the manic conditions of February 2012, any delay to the speed at which the installation could be completed was not in their interests. The main roof of the bungalow has a gable at both ends and is made cruciform by a lower lower roof running across it with hipped ends; this means the panels look out over the "side" back garden and most visitors fail to realise I have PV panels.

The portrait row of panels are only half a tile length back from the gutter (8"). This means that in winter the melting snow slides straight down the panels and, with a bit of luck, jumps the gutter. Excellent from the point of view of power generation but might give concern to an insurance company, if visitors use the path below the gutter. ]

The sniping continues:
http://eon.businesswire.com/news/eon/20130701006390/en/SolarWorld/best-solar-panels/home-solar-panels

http://www.solarworld.de/en/service/faq/

http://www.pv-magazine.com/news/details/beitrag/solarworld-q1-losses-surpass-50-million-_100011515/#axzz2ZEHHm9gz

http://www.pv-magazine.com/news/details/beitrag/eu-prosun-claims-pv-duties-will-create-jobs-_100011256/#axzz2ZEHHm9gz

http://www.businessweek.com/news/2013-06-18/solarworld-holders-lose-95-percent-in-debt-deal-as-qatar-may-invest

Sirlaughalot

Hi Oscargrouch,

From here

https://forums.moneysavingexpert.com/discussion/comment/62602675#Comment_62602675

I don`t think jumping in head first is the best way to make a sound financial judgement. Some of the spin by these solar panel salesman has been quite incredible and i`m not surprised the industry has such a bad reputation. Here are just a few examples i have experienced.

1 - Not getting the basic roof measurements correct - Major embarrassment on their part turning up on the day of installation with a system that wont fit.

2 - Not one company to date has made reference to the house requiring a Energy Performance Certificate of d or above to qualify for the higher rate of FIT

3 - Most of the salesman have inspected the electricity meter have at my home nobody has mentioned the implications of a old analogue meter running backwards except for one on line company who has yet to make a survey.

4 - All salesman bar none have calculated a 50% energy saving on the energy we use during the day even though the household during the working week is unoccupied.

5 - All salesman bar none have estimated that the system will pay for itself within 4 - 7 years when in reality the figure is closer to 10 - 12 years.

6 - All salesman have quoted a energy inflation rate of between 10-15% in their figures as opposed to the governments DECC figure of 3%.

7 - Three companies have tried to sell me a Poly system!

8 - Only two companies have mentioned the need to fit a special(dopla) valve on the soil pipe in side the loft most will just cap it (Naughty - Naughty).

9 - High pressure sales tactics by two of the companies to get me to sign a disclaimer to waiver my 7 day cooling off period in order to qualify for a discount ( dead against MCS rules of conduct).

10 - No one has mentioned the fitting of snow guards yet all the houses with panels, one exception, have them fitted.

11 - Switching of energy suppliers (solar panel) is frowned upon by the big six energy companies according to some installers and they can be quite intimidating when switching and making FIT payments

With a product you need to last 20 years a few months taking my time to make the right choice is not a problem for me and thanks to the positive comments of most posters i`m more than happy with my progress.

Thanks SL

EricMears

Sirlaughalot wrote: »

3 - Most of the salesman have inspected the electricity meter have at my home nobody has mentioned the implications of a old analogue meter running backwards except for one on line company who has yet to make a survey.

That's really not a 'problem' at all.

If indeed your meter does start going backwards (or if it's one of the rare models that decides to charge you for exported units) your meter will be changed for a model that works properly at no cost to you.

You may even make a few bob on the deal if the meter isn't changed promptly when you report the circumstances.

EricMears

Sirlaughalot wrote: »

8 - Only two companies have mentioned the need to fit a special(dopla) valve on the soil pipe in side the loft most will just cap it (Naughty - Naughty).

As I explained on the generation thread: in the majority of cases it would be perfectly legal to cap a SVP. They are there to vent the sewer pipes and if a near neighbour has a SVP you don't strictly need one too.

Sirlaughalot

EricMears wrote: »

That's really not a 'problem' at all.

If indeed your meter does start going backwards (or if it's one of the rare models that decides to charge you for exported units) your meter will be changed for a model that works properly at no cost to you.

You may even make a few bob on the deal if the meter isn't changed promptly when you report the circumstances.

Thanks Eric,

But when my readings show a negative usage how do they calculate my bill? If for example they go on my direct debit set up for x amounts of average KW used than i`m actually losing out due the the energy savings i make from the solar panels.

Sorry to be a pain!

SL

EricMears

Sirlaughalot wrote: »

Thanks Eric,

But when my readings show a negative usage how do they calculate my bill? If for example they go on my direct debit set up for x amounts of average KW used than i`m actually losing out due the the energy savings i make from the solar panels.

Sorry to be a pain!

SL

Even though you're paying by DD, a 'real' bill is calculated every quarter and is (or should be !) used to adjust your DD amount. For instance, my DD was £70 pcm when SPs were fitted and reduced (gradually) to £40 over next 18 months.

And any errors arising during the period when meter is running backwards should be corrected in negotiation with yourself. Indeed, you stand to make a profit on that:-

e.g. they might say "you used an average of 10 kWh per day in this quarter last year so we will charge you on the basis that we supplied that this year too". You reply "but I generated an average of 9kWh/day so just charge me for 1 kWh/day". In reality, you won't have used everything you generated but supplier can't possibly prove that you didn't. Remember also that if you tick a box on your FIT application form to say that meter is running backwards it becomes supplier's responsibility to correct situation asap. You can't possibly be held responsible for their failure to act promptly.

Sirlaughalot

EricMears wrote: »

Even though you're paying by DD, a 'real' bill is calculated every quarter and is (or should be !) used to adjust your DD amount. For instance, my DD was £70 pcm when SPs were fitted and reduced (gradually) to £40 over next 18 months.

And any errors arising during the period when meter is running backwards should be corrected in negotiation with yourself. Indeed, you stand to make a profit on that:-

e.g. they might say "you used an average of 10 kWh per day in this quarter last year so we will charge you on the basis that we supplied that this year too". You reply "but I generated an average of 9kWh/day so just charge me for 1 kWh/day". In reality, you won't have used everything you generated but supplier can't possibly prove that you didn't. Remember also that if you tick a box on your FIT application form to say that meter is running backwards it becomes supplier's responsibility to correct situation asap. You can't possibly be held responsible for their failure to act promptly.

Thanks Eric sounds a bit IF BUT/HIT or MiS to me and could get protracted. As i have already mentioned i change my energy supplier regularly(which has saved me literally thousands over 5 years at no extra cost i may add) so this could be a repeat scenario time and time again if the supplier fails to replace the meter quickly.

I`m still a bit baffled why none of the salesman have made any mention of this issue when they had a look round in the meter cabinet.

If i was the salesman i would have replied " Hey mate your on a good thing here your meter will go backwards and this means even bigger savings for you pal. Blah Blah Blah!"

Thanks

SL