New system, string or micro inverters

[cdrive]

Hi all, I looking at having a new solar panel system installed in kent and would like some advice if you could spare some time.

I have been looking at getting installed around 6-8 kw system. If I go for an 8kw system I would have shading issues on a bottom row of panels (spaced over two roofs and detached garage roof).

I could go for a 6kw system (over one roof and detached garage roof)I wouldn’t have any shading issues or I could go for somewhere in-between.

I have been looking at getting the power one micro inverters with either suntellite, 8.33 Gallium or solarworld all black panels. (Please let me know if they are any good).

The main reason I like the idea of the micro inverters is that I can see if any part fails very quickly and where it is (and sort it out myself if needed). The other reason is that I have been told that they produce better results as the start on lower power compared to a SMA string inverter for example.

What do you think would be the better way to go?

 

[jason121]

Have a good read at this thread Optimisers or micro inverter?

 

[cdrive]

Have a good read at this thread Optimisers or micro inverter?

Thanks, I have just been reading that he main thing with enphase, why I ruled it out is that's its only 215w and the panels are 250w so I would lose peak power.

I know that they come with a 20 year warrantee, is there much difference in price

 

[jason121]

The 215w work well with 250watt panels. The inverter is always undersized for solar in this country

 

[Earthstore]

There are many opinions on this, without knowing more about the site I would avoid shading where possible, less is more at times..
Or, maybe an SMA with optitrac switched on, if system design works well with that...

The truth is no one really knows which will produce the most power, they will all work but which would be the best?

 

[cdrive]

The 215w work well with 250watt panels. The inverter is always undersized for solar in this country

Ok, I'm guessing that we would have little chance of getting 250w in the UK. is there much difference in cost?

There are many opinions on this, without knowing more about the site I would avoid shading where possible, less is more at times..
Or, maybe an SMA with optitrac switched on, if system design works well with that...

The truth is no one really knows which will produce the most power, they will all work but which would be the best?

Thanks I didn't even know about optirac, I will look into it.
What about the fault finding, I like the idea with micro inverters you can see when a panel or inverter is not working and see where it is

 

[Earthstore]

Panel failure is very rare, by the nature of how they work, over time inverter failure is possible, my opinion is I would prefer a piece of electrical equipment mounted inside, in the dry and not on the roof mounted under a panel, scaffold @ £400 per time to change them if the company complies with the law, as I have said no one can prove which is best for performance it is just opinions.

What we do know is that a well designed system with a decent string invereter produces well for many years.

As was pointed out to me the other day, if each panel should have its own inverter why haven't any of the panel manufacturers built them into their panels or made them available in the UK.

 

[SibertSolar]

They have....

 

[Earthstore]

They have....

Every day is a school day

 

[SibertSolar]

http://www.pv-tech.org/mobile/news/canadian_solar_offers_250w_integrated_microinverter_ac_module

 

[SibertSolar]

Not available for the EU market as yet as far as I am aware

 

[MCS Renewables]

scaffold @ £400 per time to change them if the company complies with the law in UK.

With Enphase micro inverter system you will know exactly which inverter or module has gone wrong and exactly where that problem is on the roof and will be able to replace if without a full scaffolding, in most cases.
You can hire a tower at your local hire centre for about £40 a day which complies with all HSE requirements. Plus the replacement inverter is Free and the installer gets £125 to replace it.


Also if a string inverter system goes wrong see this current thread : http://www.electriciansforums.co.uk...orum/87196-five-days-without-solar-power.html.
you won't lose generation and import savings for days on end.

 

[Earthstore]

With respect "Five days without solar" is an install fault due to the PV being conected to the supply wrong, it is not an inverter fault.
I fully understand that you are a big believer in enphase, but how many panels have you personally had fail?

 

[SolarCity]

Without assessing the site, there is no way of knowing exactly how much of a shading issue you believe you have. Sometimes it is much less or much more severe than a customer realises.

Having shading doesn't mean you automatically need to have MI or optimisers. Get someone to come in and design you a system properly.

 

[cdrive]

Without assessing the site, there is no way of knowing exactly how much of a shading issue you believe you have. Sometimes it is much less or much more severe than a customer realises.

Having shading doesn't mean you automatically need to have MI or optimisers. Get someone to come in and design you a system properly.

I won’t have any shading issues on the garage 3kw system.
The house will have shading issues (this time of year) if I use the on the long roof at the back (chimney on the back was removed last week), see attached photo taken at the weekend @11:45am
But won’t have any on the side of my the trees on that side are toy trees only 15ft high, but can only fit 2.5kw system.
I’m thinking that if I use the garage 3kw with string inverter in the garage. Use the side of the house 2.5kw and maybe the top of the back roof for another 1-1.5kw as it won’t have shading issues that high.