Buying Advice

[marshman]

I was referring to the the PVOutput PVLadder table sorted by efficiency -  UK only. In my opinion this gives a reasonable picture for the true long term performance - not just a snap shot on a particular day.

With regard to long term performance I have not seen any degradation on the Sharp system yet and they are comming up to two years old.  Best day December 2010 was 9th at 5.0 kWh and best December day 2011 (also 9th!) at 5.4kWh  (and the system has slightly more PM shading due to the wind turbine mast being 1.5m higher than last year).

Roger

[langstroth3]

I think the ladder is OK, if you only include systems with a years's worth of data?
 - the fact that systems with sanyo and sharp and other types are at the bottom mid and top of the list shows that really other factors such as roof slope effect "efficiency" in varying amounts depending on the season.

However - to be fair, if you do limit the list to >365 days; the top 4 systems are all sharp (ordered by efficiency).....

[wookey]

The bdpv site gives some statistics on installed kit, telling you what fraction of installs are Sanyo/Sharp/SMA (SMA have 46% of the inverters in the 15,108 installations sending in data!).

And they allow you to compare installtions based on real data but then normalised for slope/direction. They also have yeild graphs for regions (counties in the UK). But what they don't have is normalised yield by equipment type, which would be interesting. I'll ask them to put it on the to-do list.

They also have a really nice - compare with all systems within 100km that put in data this month. But becuase it's monthly it's quite noisy. So in june 2011 I (Sharp+Fronius, 2009-10)was in the top 1% of generators within 120km (4th), but in July I was 17th out of 21. This could well be due to month-end reading being a couple of days late, I guess. Typically mine is ranked about 1/3rd of the way down the list. You could look up which panels everyone uses. Morus 3km down the road (2011-02) does ~5% better than me on average and has Romag panels with SMA inverter. Greenpark (sharp +fronius 2010-04) much the same as morus. Ceebee (Sanyo HIP 2008-03+SMA) gets about 5% less on average. So far, in general, newer systems seem better.

Lots of sharp systems in the top 10 (on PVoutput.org's list) could just mean that there is a high proportion of sharp systems registered, especially if they are not normalising the data for slope/direction. It doesn't necessarily mean they are better.

Also now this has been going for a few years just giving 'manufactuer' as a classification is not really sufficient. One manufacturer can have panels with different generations/types of cells by now.

[Rich]

I've got Sharp panels on a 3.9kWp system, and generated 10kWh on 18 December, ie 3 days before the shortest day.  Oh, and that was in Cumbria, not the south coast.  Also managed 24kWh on 2 separate days in September, so fully expect to hit 30kWh in a day when conditions are favourable in May/June/July time.
Together with what seems to be superb build quality, I don't think you can knock the Sharp panels at all.