Is £200 for 60 PV watts good value?

Vortex · Post by **Vortex** » 16 Dec 2009, 08:06

Maplins are doing a deal - is that good value?

Aurora · Post by **Aurora** » 16 Dec 2009, 08:12

I also spotted that offer. Apparently, they've reduced the price by £100.00.

http://www.maplin.co.uk/Module.aspx?Mod ... &U=storage

Vortex · Post by **Vortex** » 16 Dec 2009, 08:20

Yes ... but is it worth it????

contadino · Post by **contadino** » 16 Dec 2009, 08:45

Aurora wrote:I also spotted that offer. Apparently, they've reduced the price by £100.00.

http://www.maplin.co.uk/Module.aspx?Mod ... &U=storage

They must've put it up £50 before they bought it down.

In answer to the question, £200 is about normal. Not a bargain.

Post by **adam2** » 16 Dec 2009, 09:03

Best avoided IMHO.
The modules appear to be of amorphous silicon which is less eficient than other types.
Although it could be argued that sunlight is free and eficiency therefore unimportant, it does mean that the modules are much bigger than crystaline ones, which makes transport and mounting more problematic.

Many such modules use thin window glass which shatters if you fart near them.

Reputable PV module rate the output under STC (standard test conditions) which although optimistic, is at least a level playing field to compare differing brands.

These modules may not be rated under such conditions, and the actual output therefore less than expected.
They may be rated in chinese watts.

Aurora · Post by **Aurora** » 16 Dec 2009, 09:07

Chinese watts?

Post by **adam2** » 16 Dec 2009, 10:31

Aurora wrote:Chinese watts?

A slang term in the electrical industry for ratings of cheap Chinese electrical goods, that are misleading, but not actual lies.

For example a 60 watt PV module from a reputable firm, will either produce at least 60 watts*, or will have a close tolerance of perhaps plus or minus 2%.

A budget Chinese module rated at 60 watts, will probably produce about 40 watts under the same standard test conditions that give 60 watts from a reputable one.
This not an actual lie, since the manufactuerer will state in the small print that "PV modules are tested under approved test conditions" this will be under perhaps an insolation of 1.25 KW per sqaure meter, rather than the accepted international standard of 1.0 KW.
The "60 watt" module will therefore only produce about 48 watts under accepted test conditions.
They will then state that power output is "subject to a manufacturing tolerance of +/- 20%"
The actual output will therefore be about 40 watts, without any actual lies.

Cheap chinese inverters are notorious for being rated in chinese watts.
An inverter from say Xantrax, rated at 2,000 watts, will supply 2,000 watts continually, at any normal room temperature (up to say 30 degrees) and at any normal battery voltage (down to say 11 volts for a nominal 12 volt system)

A budget chinese inverter rated at 2,000 watts is probably only suitable for 1,000 watts continous.
The 2000 watts is not an actual lie, since in the small print the following is likely to be stated.
"2,000 watts for up to 30 minutes"
"At a battery voltage of 14.4 volts" (much less at 11 volts)
" At a room temperature of 15 degrees" (less at 20 degrees, and much less at 30 degrees)

Chinese electric cable is often slightly smaller in cross section, and shorter in length than one might expect.
Again this is not a lie, since it will be stated in the small print that "all dimensions are subject to a manufacturing tolerance of +/- 10%"
Therefore 100 meters of 2.5mm cable may turn out to be 90 meters of 2.25mm cable.

Aurora · Post by **Aurora** » 16 Dec 2009, 13:29

Thanks for the feedback Adam.

PhotoVoltaicsUK · Post by **PhotoVoltaicsUK** » 19 Dec 2009, 10:39

Thanks for that Adam. Really interesting to know about the different industry standards and measurements.

breezyenergy · Post by **breezyenergy** » 22 Dec 2009, 08:43

I agreed with you that some Chinese products like what you said, but not all products,now more and more Chinese factory pay attentions to the quality.

www.breezyenergy.com

Mitch · Post by **Mitch** » 23 Dec 2009, 17:11

I do agree with you Breezy. I have a 20 amp, 13.8 volt switch-mode power supply which I use as a battery charger. It was not "cheap" - £280.00 when I bought it in 2003 - but I was dsmayed to see it had "Made in China" stamped on it!! It's now 6 years old and gives me 27 amps for days at a time with no ill effect. Same as my 3Kw inverter, I have over-loaded it more times than I can count, and it just shuts down and waits patiently to be reset, also 2003 and still going strong.

It's just a pity that so many Chinese companies have conspired to give Chinese goods a bad name. Having said that, I still think it's true that most "cheap" Chinese goods are of poor quality -but then "you get's what you pay's for" I suppose.

High quality Chinese products DO exist, unfortunately mainly at the top end of the market.

nnnnnn · Post by **nnnnnn** » 25 Dec 2009, 18:56

I have pretty much those same panels (bought from Maplin!), they put out their rated power plus a bit more. £200 Is not really cheap though, I paid £29.99 for 13W panels in a sale a few years ago.

Pro's
Cheap?
Put out reasonable power in most light
Strong (a dropped a brick on mine from about 2 feet by accident and they did not even crack) The box claims they can withstand 2" hailstones

Drawbacks
Big for their rated power
Heavy
Can not attach your own wires directly (no junction box)

If I were buying in this price range I would try ebay, cheapest there is £150 for monocrystalline

http://shop.ebay.co.uk/i.html?_trkparms ... 286.c0.m14

I think the Chinese reputation for making poor quality will disappear soon most things are pretty decent and at least do what they should. British products aren't significantly better these days (probably because they are made in China and assembled un the UK but....)

Post by **adam2** » 19 Jun 2010, 09:51

And just to show that my concerns are not limited to goods imported from china, beware of fake electric cable from turkey, claims to be BASEC approved, but has a smaller cross section than stated.

I wonder how much has been installed ?
Along with fake circuit breakers ?

Linkhttp://www.basec.org.uk/news/basec-news ... sp?news=86

RenewableCandy · Post by **RenewableCandy** » 19 Jun 2010, 16:17

Ah Turkey...the wonderful country full of "earthquake-proof" houses

emordnilap · Post by **emordnilap** » 19 Jun 2010, 21:20

http://www.youtube.com/watch?v=Z390ijMvAlc