Solar PV

colrow

I'm looking for a good cheap supplier of PV panels, I contacted a company in China and they do a 100 W panel charge controller and 300W invertor for about $300 and $120 shipping.

Is this a good deal ?

Can anyone recomend any cheap sources for pv panels

Cheers

quentingargan

There are a few decent ones on Ebay and prices are falling there as elsewhere on the PV market. Ex China prices were about €2.70 per watt a couple of years ago with the rush on the Spanish feed in tariff etc. They've come down a lot since then.

Are you looking for an off-grid system? If so, the inverter can be sourced in car accessory shops, and sometimes in Aldi etc. If you want a grid tied system in Ireland though, the inverter must comply with EN50438 with specific Irish variants, which is a bit of a nuisance...

colrow

Thanks Quentin

I got a 60 W panel from Maplin a year ago but havent got round to fitting it yet, it cost £200 on special offer down from £300.

The plan is to fit it on my wood shed, and run 4 11w efl's off it, via battery invertor

A friend hasn't got any electricity in her cottage and uses a petrol generator to charge a battery to give her a few hours of light each night and she's interested in getting a pv panel to charge the battery instead.

quentingargan

Unfortunately, using solar for lighting is a bit of a mis-match. When you need longer hours of lighting is in winter, the solar PV is giving as little as 12% of its daily summer production. But if there is a backup genny, it will make a contribution OK.

ccsolar

Hi Calrow
The shipping cost from china sounds great @ $120 but I think if you check with a shipping agent you might find that this figure will increase to about €500, watch out for the CIF/enviromental/handeling/vat/duty and customs clearence charges, these will all have to be paid before the item is released.
I know a lot of people are getting caught this way.
The PV panel is a great idea, best of luck with it.

CC

colrow

Thanks CC, it seems it would cost me more trying to import direct than buying off ebay. The idea seems a bad one for my friends place. I'm going to hook my 60 watter up when I get back in April, and see how that runs, I was going to run 4 11watt efl bulbs to see how long they would run for, but it seems that a modified sine wave invertor wont run them, i'll have to look for some other bulbs, maybe try 12v fluoresents straight of the controller

quentingargan

I run my house off-grid using 24VDC CFL bulbs. If you pm me I can give you a link to the place I bought these. More efficient than using an inverter. Q

quentingargan

A couple of people asked by PM about where I got the bulbs so I thought I should put in a p.s. on this.

DC circuits should only be wired using stranded wire. Note that your house is probably wired using solid twin and earth. I don't know what the long term prognosis is for this, but solid is fine for AC because the electrons just vibrate up and down 50 times a second. In the case of DC, the electrons actually flow, and they do this along the surface of the wire. Stranded wire has a far higher surface area for this. That's why your car is wired in stranded, and all battery and PV circuits should be wired likewise.

Secondly, the bulbs are screw-in fittings rather than bayonet, and you have to get the polarity on this correct. You can't use standard lamp bayonet fittings as there is no way of ensuring that the polarity is correct. Q

colrow

Hi Q,

I went to the site you pm#d me but they wanted €40 euro for delivery, and for 4 bulbs and sockets that made it €80.

I found another place that I got four 20W bulbs with 7.50 delivery charge.

They also had this bit of info below :-

I'll pm the site to anyone that asks, mind you the main concerns of the site is a million miles from solar power !!!

1) Using BC / B22 light fittings - If lamp does not illuminate, lamp may need removing, turning 180 degrees and re-fitting as they are polarity sensitive. See image

---

>

2) ES / E27 - Centre contact is + positive

N.B: All lamps are reverse polarity protected so that there will be no damage if polarity is incorect for your light fitting (if lamp does not illuminate remove and refit B22 or change over supply cables on E27 fittings

quentingargan

colrow wrote: »

...the main concerns of the site is a million miles from solar power !!!

Haha, I'm surprised you could open that one in Saudi. I'm in a restaurant on the laptop and I'm afraid to open it in case I get chucked out before I finish my grub...

Thanks for that though. Now that I think about it, I hadn't been so freaked about the post because I was buying 14 bulbs.

colrow

Lol well I didn't explore any of the site.

Any ideas on a smallish 12 volt sy 50 Watt water wheel generator, I've tried looking on google can't find anything

quentingargan

colrow wrote: »

Lol well I didn't explore any of the site.

Any ideas on a smallish 12 volt sy 50 Watt water wheel generator, I've tried looking on google can't find anything

Actually the site is benign, but its URL sounded more raunchy.

I have a small Canadian water turbine and have also used one of the cheaper Chinese ones (which produce 240V AC ready to use). The Canadian company used to do a smaller version, but even this was about €1500 by the time you shipped it in.

If you have a suitable water source, a turbine is a real no-brainer - far more consistent and cost effective than either wind or solar. There was a company in New Zealand making one based on old washing machine parts, but I don't have a name. There is a bloke in Scotland who sells all the bits to make your own turgo wheel, and I think also has 24V DC generators, but not 12V. I can pm you his contact info, but again I would think you are looking at over a €grand. Q

nulabert

I thought I read somewhere that PV panels are only 11% efficiency and require direct sun light to work i.e., won't work in overcast conditions?

quentingargan

nulabert wrote: »

I thought I read somewhere that PV panels are only 11% efficiency and require direct sun light to work i.e., won't work in overcast conditions?

The efficiency doesn't matter really - just means more roof space is taken up. In fact, efficiencies have improved over the years and most commercial panels are more efficient than this.

If a panel is stated as producing 200 watts at a daylight energy of 1,000 watts per sq m, then it will produce that 200 watts in bright sunshine.

PVs don't lose efficiency very much as light levels fall. So if the daylight energy falls to, say, 400 watts per sq m, then that panel will produce pretty close to 40% of its stated output, or 80 watts at that time

nulabert

Quote:
If a panel is stated as producing 200 watts at a daylight energy of 1,000 watts per sq m, then it will produce that 200 watts in bright sunshine.

PVs don't lose efficiency very much as light levels fall. So if the daylight energy falls to, say, 400 watts per sq m, then that panel will produce pretty close to 40% of its stated output, or 80 watts at that time

Its sunshine, i.e. direct radiation that falls on these panels to get them going? Incident radiation is no good for PV panels? This must be where the 11% comes from. We have overcast days nearly all year round so if its not direct sunlight, then they don't work to 100% but more like 11%?

A guide to hours of sunshine can be found here. Pity we're not living in the Sahara, they get plenty of Sun over there!!:D
http://www.met.ie/climate/sunshine.asp

quentingargan

nulabert wrote: »

Its sunshine, i.e. direct radiation that falls on these panels to get them going? Incident radiation is no good for PV panels? This must be where the 11% comes from. We have overcast days nearly all year round so if its not direct sunlight, then they don't work to 100% but more like 11%?

PVs convert all light into energy, whether it is direct (sunlight) or diffuse. But if light is diffuse, it obviously has less energy in it for the panel to convert. The 11% comes from the panel turning 11% of the energy that falls onto it as daylight into electricity. In fact most modern panels do a lot better than that, depending on type.

I can't think of any system that converts 100% of energy from one form to another without losses along the way, although energy cannot be created or destroyed. In the case of a PV, most of the energy falling as light is either converted into heat or reflected back. Typically 15% of the energy is converted into electricity.

Joe 90

quentingargan wrote: »

I can't think of any system that converts 100% of energy from one form to another without losses along the way, although energy cannot be created or destroyed.

Well I suppose that the element of an elecric heater is 100% efficient at turning electricty into heat. Pity we can't go the in the other directon so easily.:)

PositiveNegativ

Trying to get an understanding of just how realistic PV panels are for me.

Current annual electicity usage is 1650 kw.
Dormer style house, so large roof area, unfortunately facing east/west but unshaded. Located on Wicklow/Wexford border.

Anyone got real world figures for the cost (parts, fitting etc) per m2 of PV panel and how many kw I could expect per m2/year

Thanks

heinbloed

PositiveNegative asks:

"Anyone got real world figures for the cost (parts, fitting etc) per m2 of PV panel and how many kw I could expect per m2/year "

There are many different types of PV panels, different prices and efficiency.
The best answer would be a written and signed guarantee from an installer, including the amortisation.

quentingargan

PositiveNegativ wrote: »

Trying to get an understanding of just how realistic PV panels are for me.

Current annual electicity usage is 1650 kw.
Dormer style house, so large roof area, unfortunately facing east/west but unshaded. Located on Wicklow/Wexford border.

Anyone got real world figures for the cost (parts, fitting etc) per m2 of PV panel and how many kw I could expect per m2/year

Thanks

There is some very good simulation software that can assess output for most locations. One free one is from Retscreen in Canada. I don't think you will find the finances stacking, but solar PV is good for meeting part L compliance if you are building a holiday home, where perhaps solar thermal would be troublesome.

PositiveNegativ

Thanks for that, I'll have a look at/for Retscreen.