Cell Quality - does it make a difference?

butako

So I have a few quotes from different companies for 4kWp systems. The big names like IKEA and E.ON are coming out cheaper than the local independent installers (e.g. £5.5k from Ikea, vs £7k from local). The local firm explains this as Superior Quality Cells & Inverter with Superior Warranty and Superior components etc etc.

So the big question is, does it really honestly make all that difference? Or is it all just Sales?
£1.5k price difference is a lot of electricity and adds years on the breakeven.

Ikea: Q-Cells Mono 295W
Local supplier: Perlight 300W or SunPower x335.

Martyn1981

Your enjoying the same dilemma that all of us had going back 7 or 8 yrs.

I'd suggest it's mostly sales pitch. What you can do is ask for the make and model of the inverters (you may already have them) and look at the specs. Look for the euro efficiency rating. They'll probably be somewhere in the 95%-97% range, but see if there's any significant difference, and also the warranties that come with them.

Panel efficiencies don't matter so much as that's already reflected in their Wp ratings. For instance, assuming all those panels are the same size, approx 1.6m2 then their higher outputs reflect a higher efficiency, but presumably also a higher price.

If you are having 13 to 14 panels installed (no room for more?) then the higher price would mean say 4.13kWp (14 x 295Wp) v's 4.69kWp (14 x 335Wp), so you get more PV for your money, but that extra 0.5kWp is very expensive at £1.5k.

If the higher spec system is also ~4kWp, then I'd assume you are paying more money, but getting one panel less installed. Not great.

Simply based on the info you've posted, the Ikea deal does look a lot better IMO.

Lastly, the question we always ask - why 4kWp? Is that maxing out roof space? If not, then it might be worth adding a few more panels. If the installers point to rules and regs, then you respond with "add a slightly bigger inverter, but cap its settings at 3.68kW output to meet the local grid (DNO) restrictions".

Zarch

What inverters are being suggested by EDF/Ikea(solar century?) and the independents?

Are the independents going down the SolarEdge / power optimisers route so to mitigate any shading issues by allowing each panel to work independently?

Are the independents adding other 'guff' on to the quotes that is not required? Thinking voltage doctors etc?

Are the independents adding other stuff that could be useful; iBoost for hot water tank heating?

Probably worth comparing the small details in the quotes rather than just the headline figure of the panels?

michaels

We paid under 5k for our 4kw solar edge installation 3 years ago so to me all your quotes sound a bit expensive.....

hollie.weimeraner

michaels wrote: »

We paid under 5k for our 4kw solar edge installation 3 years ago so to me all your quotes sound a bit expensive.....

I paid £5,600 for a 4Kw system 3 years ago so likewise it's expensive. If you tell us where you are located I'm sure there are people on here who will be willing to recommend installers

butako

My latest quote from a local supplier is recommending Sunpower 335 with SolarEdge and iBoost, £8k for 4kWp! And I have no shading. IKEA SolarCentury is about £6k for QCell 285, Goodwe inverter and iBoost.
I am in Kent. Any recommendations for a reasonable down to earth supplier?

butako

Correction. Local supplier quotes £9k for 4kWp system. I cannot believe the quality of panels could make so much difference to justify such price differences?

Merlin139

butako wrote: »

My latest quote from a local supplier is recommending Sunpower 335 with SolarEdge and iBoost, £8k for 4kWp! And I have no shading. IKEA SolarCentury is about £6k for QCell 285, Goodwe inverter and iBoost.
I am in Kent. Any recommendations for a reasonable down to earth supplier?

I cannot see why an installer would recommend SolarEdge if you have no shading. The premium makes no sense. I do have a SE system but I suffer around 10% shading and SE makes a big difference. I paid under £6K for my system in May 2014 and have today passed 18 MWh's generation. It also included an Iboost.

I did a search on Sunpower 335 and came up with the following @ £287.50 each.

https://www.renugen.co.uk/sunpower-x21-335w-blk-335-watt-solar-panel-module/

I would suggest the installer is likely to be making a large mark-up. My thinking for the increase in price maybe down to the lack of work being carried out and having to make more profit to stay afloat.