Considering going ahead with a quote

Alstrada

Split over two roofs front & side in scotland
Supply & fit complete 4 kW using micro-inverters & monitoring
£ 5,850.00 (Suntellite Panels)
£ 6,000.00 (8•33 Black Eternity Premium Range 833)
£ 6,100.00 (Black Solarworld Modules)

I'm just looking for advice,

zeupater

Hi & welcome to the forum ...

First a question .... why micro-inverters, do you have shading issues ??

Z

tunnel

For a system using "micro's" the prices are about right(no difference in the panels really)


For a system that may not need "micro's" then the prices are top heavy!


So can you answer Z's question first?

Alstrada

Hi, thank you for replying, I've no shading issues, front roof almost east facing & side is almost South, the hip of the roof separating the two roof areas is south facing, the Side gets the sun longest.
The guy that came out said the micro invertors were the way to go as they are more efficient, they kick in at lower volts and are better for northern UK as they work better in dull days,
He sad the microcrystalline panels also work better in dull day's
This is pretty new to me, I do hope to get this done before the next tariff drop.
I'm interested to hear from neutral informed people
Thanks again

Alstrada

They just said the strings are old technology and the micro invertors were more efficient and in the future most all would be done like that as its a better way.
Thanks

zeupater

Hi

If neither roof aspect throws a shadow on the other -and- there's no shading from trees/buildings/lampposts etc -and- there aren't any shadow creating dormer windows or chimneys in the roofline, then you may not need to lay out the extra on micro-inverters unless there's a large imbalance between the number of panels on each roof (for example 12/13 panels on one roof and 3/4 on the other) which could create low voltage conditions, thus reduced generation efficiency, on the smaller array for some inverters .... if that's not the case then you'd probably be better off with a standard dual MPPT inverter.

Micro-inverters (and Optimisers) increase efficiency by mitigating the effect of shade and also claim to have better MTBF (design life expectancy) than standard inverters, however, you'd only have one inverter (which would be in an accessible position) against (say) 16 micro-inverters attached to the bottom of panels on your roof ... this simply multiplies the inverter-related potential points of failure by 16 and increases the cost of access, requiring scaffold/tower access to the units, the cost of which will likely not be covered by any long-term guarantee. As for the efficiency difference without any shading issues - just take that sales pitch with a 'pinch of salt' - even if it's true the extra expenditure wouldn't be justified .... effectively they're great if you need them, but if you don't most (including members of this forum with micro-inverters or optimisers) would probably advise you to play safe & get quotes based on a decent make dual MPPT inverter ....

HTH
Z

tunnel

Alstrada wrote: »

The guy that came out said the micro invertors were the way to go as they are more efficient, they kick in at lower volts and are better for northern UK as they work better in dull days,
He sad the microcrystalline panels also work better in dull day's

Unless those panels and micros are 20% better than a standard dual MPPT inverter then they're not worth the difference price wise as a standard install should be around the £5k mark.


Was the leccy savings worked out on 50% use with a 8-10% annual increase on your import costs by any chance?

ispookie666

I have enphase micros .. the company says it will cover the cost of scaffolding during warranty years.
Would not having high voltage DC be better?

Martyn1981

Alstrada wrote: »

They just said the strings are old technology and the micro invertors were more efficient and in the future most all would be done like that as its a better way.
Thanks

Hiya Alstrada. I've got power optimisers on one of my rooves (as does tunnel). They do a great job of mitigating shade problems. But, they do add cost, and complexity.

If you don't have shading issues then as mentioned by others, you'll need a higher performance just to balance out the higher cost. If the cost is £500 to £1000 more, then as tunnel said, you'd need 10% to 20% more generation simply for your return on investment to come out the same.

If you had shading then 10% to 20% is possible, but I seriously doubt it if the rooves are relatively shade free.

This isn't a criticism of micro's or PO's, they both do a great job, but you might not have a job for them to do.

Yes, string inverters are old technology, in the sense that they've been around longer, but not in the negative connotation.

Have you found the PV FAQs yet? They were written specifically for those like you

"I'm interested to hear from neutral informed people"

They'll give you some basic background info on PV.

A split system E & S sounds great, and your prices so far look good, so nothing to worry about, just keep learning and getting quotes.

I appreciate you are keen to get in before the next FiT reduction, but it's only 3.5%, and you've already missed 3 such reductions this year (and many, many more in previous years), so don't worry too much, it's equivalent to a price reduction of about 2.5%, and hopefully you'll manage more than that, even if you miss the 1/10/15 deadline.

Mart.

Martyn1981

ispookie666 wrote: »

I have enphase micros .. the company says it will cover the cost of scaffolding during warranty years.
Would not having high voltage DC be better?

Hiya. I've heard the same elsewhere, but is this something being offered by the installer rather than Enphase?

I've looked at the M250 & M215 warranties and they both seem to say the same:

Para 4 - The Limited Warranty covers a replacement unit to replace the Defective Product, but does not include labour costs related to (1) un-installing the Defective Product or (2) if applicable, re-installing a repaired or replacement product.

Para 5 - The Limited Warranty does not cover costs related to the removal, installation or troubleshooting of the Warranty Holder’s electrical systems. The Limited Warranty does not extend beyond the original cost of the Enphase Microinverter.

Mart.

Alstrada

Thanks for the replies, each company says, whatever you do don't go with that company, and don't get a battery system or whatever you do don't get a string system makes sure it's micro invertors.
I do like the idea of the invertor being easily accessible for a future replacement and hope to get one that's easy to add a battery to in the future