Opinions please

flotmangooner

Hi All,
My wife and I are seriously considering investing in a Solar PV system and have obtained a few quotes so far. From the info provided below, what are your opinions as to the best one ?

NR15 postcode (south Norfolk), WSW facing roof, no shading

• Hyundai 218w panel, 3.924kw system, 3130 est output, Theia3800s inverter £12700
• Trina 240w panel, 3.84kw system, 3063 est output, Theia3800s inverter £12095
• Samsung 247w panel, 3.952kw system, 3392 est output, Sunny boy 3800 inverter £11100
• Kinve 250w panel, 4.00kw system, 3286 est output, Sunny boy 4000tl inverter £12000

One other question regarding the Inverter - a guy who came to see me on Saturday (still waiting for his quote) said he would never ever place an inverter inside a loft - all his inverters have been installed externally on a wall that does not get any direct sunlight. He said anyone who installs an inverter inside a hot stuffy loft does not know what they are doing. Any opinions on this please ?

Grateful for any advice
Many thanks

Cardew

flotmangooner wrote: »

Kinve 250w panel, 4.00kw system, 3286 est output, Sunny boy 4000tl inverter £12000

The experts will be along shortly I expect.

However I was under the impression that the higher rate if FIT was only paid for systems less than 4kWp(<4kWp) and thus a 4kWp system moves it into the next(lower) band of FIT.

Quite happy to be corrected if I have misunderstood.

flotmangooner

Cardew wrote: »

However I was under the impression that the higher rate if FIT was only paid for systems less than 4kWp(<4kWp) and thus a 4kWp system moves it into the next(lower) band of FIT.

Quite happy to be corrected if I have misunderstood.

I think you right - well spotted. I think they may have rounded it up to a nice round figure but i will double check. If it is a 4kw system then they will be ruled out

zeupater

flotmangooner wrote: »

I think you right - well spotted. I think they may have rounded it up to a nice round figure but i will double check. If it is a 4kw system then they will be ruled out

Hi

DECC banding classifies as up to and including 4kW with the next band being >4kW .... http://www.decc.gov.uk/assets/decc/What%20we%20do/UK%20energy%20supply/Energy%20mix/Renewable%20energy/policy/fits/1826-table-of-generation-tariffs-2020.pdf .... there's also the ongoing argument of what the exact definition of TIC (Total Installed Capacity) is, but that's another issue ....

HTH
Z

Freepost

zeupater wrote: »

Hi

DECC banding classifies as up to and including 4kW with the next band being >4kW .... http://www.decc.gov.uk/assets/decc/What%20we%20do/UK%20energy%20supply/Energy%20mix/Renewable%20energy/policy/fits/1826-table-of-generation-tariffs-2020.pdf .... there's also the ongoing argument of what the exact definition of TIC (Total Installed Capacity) is, but that's another issue ....

HTH
Z

What is the benefit of installing a 4kW system if you can only export 3.68kW (230v x 16A) the rest being dissipated by the inverter.

Wouldn't it make more sense to buy a smaller system therefore saving a few hundred pounds? I don't mean to be pedantic ... still learning about this subject!

F.

zeupater

flotmangooner wrote: »

Hi All,
My wife and I are seriously considering investing in a Solar PV system and have obtained a few quotes so far. From the info provided below, what are your opinions as to the best one ?


NR15 postcode (south Norfolk), WSW facing roof, no shading

• Hyundai 218w panel, 3.924kw system, 3130 est output, Theia3800s inverter £12700
• Trina 240w panel, 3.84kw system, 3063 est output, Theia3800s inverter £12095
• Samsung 247w panel, 3.952kw system, 3392 est output, Sunny boy 3800 inverter £11100
• Kinve 250w panel, 4.00kw system, 3286 est output, Sunny boy 4000tl inverter £12000

One other question regarding the Inverter - a guy who came to see me on Saturday (still waiting for his quote) said he would never ever place an inverter inside a loft - all his inverters have been installed externally on a wall that does not get any direct sunlight. He said anyone who installs an inverter inside a hot stuffy loft does not know what they are doing. Any opinions on this please ?

Grateful for any advice
Many thanks

Hi

The SB4000TL is a good quality transformerless inverter so I'd look at building a 4kWp system around that ... I know nothing of the panel selections that have been posted except that they're likely to be at the cheaper end of panel prices ... suggest that you check whether the panels are mono or poly, what the mounting system is, how they will fix to the roof (drill tiles or do it properly), how they integrate into your current wiring (existing consumer unit/additional consumer unit) etc.

If you go for the SB4000TL inverter get the installer to throw in a Sunnybeam remote bluetooth monitor to seal the deal ... think of it as being the mudflaps or mats on a new car

Personally, I like to support British manufacturing jobs where possible ... if you're like minded the panel choice is between Sharp & Romag. I can see no reason why you couldn't have a system based on British made monocrystalline panels and the SB4000TL with a decent mounting frame within the price band you mention above.

I tend to agree with the installer on not putting the inverter in the loft, it will run hotter which will effect the efficiency if it goes over 40C and heat is one of the great killers of electrical & electronic equipment. If you can possibly place the inverter inside an integral/attached garage close to the mains meter without seriously extending the DC power run it would be worth considering and the extra DC losses can be offset by using larger cables (eg 6mm instead of 4mm).

You can double check the performance figures for the various panels you mention with SMA inverters by downloading the SMA SunnyDesign software from here ... http://www.sma.de/en/service/downloads.html ...

HTH
Z

zeupater

Freepost wrote: »

What is the benefit of installing a 4kW system if you can only export 3.68kW (230v x 16A) the rest being dissipated by the inverter.

Wouldn't it make more sense to buy a smaller system therefore saving a few hundred pounds? I don't mean to be pedantic ... still learning about this subject!

F.

Hi

No problem, that's one of the thoughts I had when first looking into a system ....

The system will only run at maximum on very rare occasions, it's pretty cloudy at the moment and my system is producing 493W with the current house load being 380W, so I'm exporting 113W ... if the system was half the size I'd get half the production, so around 250W, but still be using 380W and therefore importing 130W .... I simply wanted to try to cover the baseload over the winter months too ...

Looking at it from a return on investment point of view, the cost/watt is lower on larger systems, so maximising the system size within any FiT band will give the best return in that band ....

Looking at sizing an inverter to the panel capacity, my belief is that running any electrical, electronic or mechanical device at full capacity reduces it's life expectancy, so I preferred to pay the extra for a little more capacity and rely on the extra efficiency delivered by a transformerless inverter to help return the extra investment .... The option for me was made even more of a no-brainer when you add the installers' price for a bluetooth piggyback card to a SB3800 to enable SunnyBeam connectivity ...

HTH
Z

thenudeone

Freepost wrote: »

What is the benefit of installing a 4kW system if you can only export 3.68kW (230v x 16A) the rest being dissipated by the inverter.
F.

I have 3.995kW of panels but a 3.68kW inverter (Fronius IG TL 3.6), with a USB stick that captures output every 5 minutes. The number of times the output gets anywhere near 3.68kW is very rare, so I'm hardly losing anything by having an inverter slightly smaller than the panel output.

I have the inverter inside in the boiler room 1) to keep it cooler than it would be in a loft and 2) to access it to review output etc.
I have slightly thicker cables from the panels to compensate for the higher losses.

It's surprising how often the fans kick in to cool itself, so I'm glad it's not in the loft.
Although they are designed to be weatherproof I think an inverter would be better without having to deal with the extremes of temperature, rain, and snow, but that's just an opinion.

Cardew

Freepost wrote: »

What is the benefit of installing a 4kW system if you can only export 3.68kW (230v x 16A) the rest being dissipated by the inverter.

Wouldn't it make more sense to buy a smaller system therefore saving a few hundred pounds? I don't mean to be pedantic ... still learning about this subject!

F.

You don't want to get too hung up on the maximum output.

Depending where you live you might never generate 4kW from a 4kWp system.

Other than in high summer you might be generating, say, 2kW from a 4kWp system. So under those conditions the bigger the system the greater the output. e.g. a 4kWp system might be generating 2kW and a 3.8kWp system, say, 1.9kW. - SIZE MATTERS;)