Solar Panel Guide Discussion

zeupater

mardycow wrote: »

the panels are german Solarworld, and the system quoted 3.185 incl an Italian inverter and a generator meter. i think the panels are about 1 m in size. not had all the details emailed through yet.

Hi

The 13 panels will be 245W then and will be about 1.6mx1m each. SolarWorld seem to have a good reputation if you forgive them for having JR wearing a cowboy hat on their website (is he still there ?).

3.185kWp on a decent roof aspect is likely to see a SAP return of around £1200pa (incl deemed export 50%) and your electricity saving is likely to be £100 although the installer will probably say ~£160 on the quotation .... so they should have mentioned a saving of around £1360/year, not £1700. Check this when the quotation arrives.

Get the installer to provide details of the inverter, the mounting system & fixing method ... if they mention that they will drill your tiles and bolt through them .... RUN :exclamati:silenced:

HTH
Z

zeupater

Lotus-eater wrote: »

Could you explain this please, I don't really understand what you are saying. I thought that the whole thing was measured and they knew exactly the amount you used?

I have about the right size roof for a 3.2 kw system looking at the way he worked it out. No more space for a bigger system.
So I'd be looking at getting a cheaper price. I just don't know where to start tbh, seems to be so many cowboys around.

He did say that about the only thing that could break would be the inverter, at a cost of about £1k he said, but that it should last 10 years, but had a warranty of 5 years.


The only other thing, is that I know the roof tiles may need replacing in a few years, which makes it a difficult decision.

Oh and he said they use Sharp panels, is there anything about the makes of panels I need to know?

Hi

What you produce is measured by a 'Total Generation' meter, it is from this reading which you will be paid the FiT, whether you use the electricity yourself or not. Additionally, you will be paid for the energy you export (currently 3.1p/kWh) and this will be via an export enabled 'smart meter'. However, most electricity suppliers are not ready to supply smart meters yet but have plans to do so in a few years time, so in the meantime you will be paid a 'deemed 50%' export rate, effectively paying 3.1p for 50% of your 'Total Generation' meter reading ..... the best way to look at it is adding 1.55p directly to the FiT until an export meter is supplied.

HTH
Z

Lotus-eater

zeupater wrote: »

Hi

What you produce is measured by a 'Total Generation' meter, it is from this reading which you will be paid the FiT, whether you use the electricity yourself or not. Additionally, you will be paid for the energy you export (currently 3.1p/kWh) and this will be via an export enabled 'smart meter'. However, most electricity suppliers are not ready to supply smart meters yet but have plans to do so in a few years time, so in the meantime you will be paid a 'deemed 50%' export rate, effectively paying 3.1p for 50% of your 'Total Generation' meter reading ..... the best way to look at it is adding 1.55p directly to the FiT until an export meter is supplied.

HTH
Z

Ah, I see, he did say that the meter would need to be changed, as I have a very old one. Maybe that means I will get the all singing all dancing one now?


He also said I needed the consumer unit changing, as I don't have an RCD one. So that's something else I need to look into, to see how much it will cost.

Lotus-eater

zeupater wrote: »

Hi

The 13 panels will be 245W then and will be about 1.6mx1m each. SolarWorld seem to have a good reputation if you forgive them for having JR wearing a cowboy hat on their website (is he still there ?).

3.185kWp on a decent roof aspect is likely to see a SAP return of around £1200pa (incl deemed export 50%) and your electricity saving is likely to be £100 although the installer will probably say ~£160 on the quotation .... so they should have mentioned a saving of around £1360/year, not £1700. Check this when the quotation arrives.

Get the installer to provide details of the inverter, the mounting system & fixing method ... if they mention that they will drill your tiles and bolt through them .... RUN :exclamati:silenced:

HTH
Z

My figures I worked out for a 3.2 KW system say that the income would be around £1350 a year, so about the same as yours.

Could you expand on the details of your last sentence please? What do the details of the inverter do we need and how should the panels be fixed?

zeupater

Lotus-eater wrote: »

Ah, I see, he did say that the meter would need to be changed, as I have a very old one. Maybe that means I will get the all singing all dancing one now?


He also said I needed the consumer unit changing, as I don't have an RCD one. So that's something else I need to look into, to see how much it will cost.

Hi

The meter changing could be because it is an old analogue one which would run backwards ... this would be a straight swap for one which wouldn't, this could be a newer analogue unit with a ratchet, or a digital meter, but it's not likely to be an export enabled meter.

The consumer unit change could just be a way of increasing the total cost of the installation, as is upgrading the earth bonding of electricity to water and gas which they'll probably also include if changing the consumer unit. An alternative would be to install a separate 'garage' consumer unit and not touching the existing house wiring at all ... this could give the additional benefit of being able to better measure the household power consumption with an energy monitor, which isn't very easy if the inverter connects directly into the household consumer unit, so talk to the installer about this possibility.

HTH
Z

zeupater

Lotus-eater wrote: »

My figures I worked out for a 3.2 KW system say that the income would be around £1350 a year, so about the same as yours.

Could you expand on the details of your last sentence please? What do the details of the inverter do we need and how should the panels be fixed?

Hi

On the inverter, it's the manufacturer and size which are important. Many installers seem to be charging top brand prices and delivering something with a lower quality image and also grossly undersizing the inverter to the panel capacity in order to maximise margins. When I was looking I had a quote for a 4kWp system with an SMA 3.3kW inverter 'or similar', it turns out that the 'or similar' was used quite regularly and that the 3.3kW was seen as including some 3kW units .

You should have a decent & reputable mounting frame, such as SEN or Schueco, as opposed to mounting with general purpose profiles as some installers appear to do. The frame should be fixed directly to the roof structure beneath the tiles with brackets which are suitable to your roof and tile types. The roof should be 'made good' with lead flashing in order to ensure it's just as watertight after installation as before. Make sure you get a 5 year warranty on the roof workmanship and that the roof work is done by roofers, not labourers who have simply been shown what to do if nothing goes wrong.

Regarding panels, Sharp & Romag are made in the UK and would support British jobs, there are good & bad european units (mainly good) and there are a lot of far-eastern panels, mainly not so good but there are some with very good reputations such as Suntech and Yingli. I'd prefer to only have panels from a manufacturer which has a reputation in other areas to protect and is well established ....

HTH
Z

keith_r59

thenudeone wrote: »

Panels could get damaged by snow or stone-throwing youths

Yes better watch out for those stone-throwing youths. :rotfl::rotfl:

mardycow

hi, quote states: click fit mounting rails and hooks, and the inverter states PVI 3000 power one. eco eye monitoring meter, haven't had a survey yet may try for another quote or 2., thanks for your input so far

zeupater

mardycow wrote: »

hi, quote states: click fit mounting rails and hooks, and the inverter states PVI 3000 power one. eco eye monitoring meter, haven't had a survey yet may try for another quote or 2., thanks for your input so far

Hi

Check the make of the mounting rails ... 'click fit' could be SEN SOL-50, if so that's a great looking system and probably as strong as they come ... see here ... http://www.sen.eu/en/mindex.php?id=58939b7b115a4797b772360bceaaad9a ... hooks will mean that they'll not be drilling your tiles, so that's good

I wondered what they were going to use to control an odd number of panels (13), the Aurora PVI3.0 (if that's what they mean by PVI3000) is a twin MPPT unit which will cope with odd strings ... see .... http://www.power-one.com/renewable-energy/products/solar/string-inverters/aurora-uno/pvi-30-pvi-36-pvi-42/series

HTH
Z

mickyduck

zeupater wrote: »

Hi

Small world, I've spent quite a few hours in the Swan Inn at Ashvale, decent beer, a bit pricey compared to my local though ....

Anyway, the SMA SunnyDesign software doesn't have the facility to resolve the meteorological data down to exact location so you'll just need to select Northern Europe/UK/London, it'll be close enough to compare panel/inverter combinations and calculate cable losses. The ability to create a location only allows a location name to be entered against a particular city's dataset.

Your PVGIS output above is using the classic dataset, this is based on averaging historical readings from groundstations and guestimating the insolation between them. The 'CLIMATE SAF - PVGIS' dataset is newer and based on averaging satellite observations down to a much smaller resolution and should be more accurate, especially in hilly areas .... this may not be the case in your particular case considering that the local met station is only about 2 miles away

When fitted you could adjust your PVGIS installed capacity to reflect the flashtest figures for you particular panel pack as delivered which will give a more realistic target, but don't forget that the panel performance will degrade over time ..... you could alternatively see this as a way to introduce a little frustration when the weather restricts production, but remember, it's only a target, it makes absolutely no difference to the actual generation .....

HTH
Z

Thanks next time your in the Swan I will buy you a beer, all pubs are pricey round here........
:beer: