Solar Panel Guide Discussion

Martyn1981

oldskoo1 wrote: »

So is the 4kW panels linked somehow to the grid limit. Bit hazy after the calc. Could have sworn I saw a post somewhere showing someone's panels producing 255v 16amp

Just because you seem interested. Back in the early years of the big PV launch in the UK (2010 to 2012 (I think)) the regs meant that capped inverters had to cap at 16A, and were generally advertised as such "16A capped".

But it was quickly realised that with our leccy supply being only nominally described as 230V, and in reality being generally higher, that 3.68kW was being exceeded, so the rules changed and the amperage cap was replaced with an actual wattage cap. Hence capped inverters now advertised as "3.68kW capped".

Mart.

1961Nick

The 'cap' can be clearly seen on this chart of my best ever day. If the cap were removed & the graph extrapolated, the overall generation for the day wouldn't be that much higher.

zeupater

1961Nick wrote: »

The 'cap' can be clearly seen on this chart of my best ever day. If the cap were removed & the graph extrapolated, the overall generation for the day wouldn't be that much higher.

Hi

Looking at the distribution it's clearly not the inverter which is capping the generation, it's simply panel temperatures from being in continuous sunshine .... our best day ever saw extended period generation plateau at ~3300W/3400W in line with yours (outside temperatures ranging between 18.7C & 20.2C), well below the capacity of the inverter ...

HTH
Z

oldskoo1

Thanks all I feel like I've learnt so much in such a short period of time.

I had a good morning this morning. Someone invited me over to see their solar install. Great guy and spent a lot of time talking me through the options. This filled in loads of gaps for me.

As it turns out he had black LG panels and a samil inverter too so I got to see the set up I was thinking of working.

The inverter and the owl monitor hooked up was really interesting. I was impressed with just a few simple changes in appliance use and habit even on a cloudy day a lot of your energy use is met by the panels.

I understand the inverter AC output reasons now. I now know how to cable the panels into my meter box and I'm looking forward to seeing what quotes I get now.

oldskoo1

Hi guys

Curious about inverter placement now.

Loft is very hot
Meter box long way down on side of house outside
House is 3 storey
Fuse board long way from meter box in centre of house
Fuse board long way from roof and it will mean visible cables from the rear of the house

Not sure the Samil is fully weatherproof
I was thinking I could locate it outside on the wall next to meter box, but can't see the display (it is wifi) and is it weatherproof.

That would mean a long DC run.

Option 2, my loft hatch is in a walk in cupboard, could put it in there then take the cables back into the loft for a long AC run down to the meter box on the side of the house.

At least the unit is indoors and can be read but it's located next to an open stairwell and potentially of it buzzes could be heard through the house.

Plus option 2 is a long AC run.

I approximated 3 to 4m from panels to inverter in loft hatch cupboard. Then 11 to 12m run back into loft and down the outside wall to the meter cupboard. I don't want any drop off from these cable runs but I also don't want inverter throttling from loft placement.

So walk in cupboard and hope there is no noise or outside and inaccessible and exposed.

Option 3, thry run a DC down the house, across the house and up into the utility, doubt the Mrs would go for that!

Any thoughts?

Thanks again

1961Nick

zeupater wrote: »

Hi

Looking at the distribution it's clearly not the inverter which is capping the generation, it's simply panel temperatures from being in continuous sunshine .... our best day ever saw extended period generation plateau at ~3300W/3400W in line with yours (outside temperatures ranging between 18.7C & 20.2C), well below the capacity of the inverter ...

HTH
Z

Generation peaks at 3440kW (according to the energy monitor - meter pulse counting), regardless of the ambient temperature.

(The current temperature is 9C & generation has peaked at 3440kWh.)

zeupater

1961Nick wrote: »

Generation peaks at 3440kW (according to the energy monitor - meter pulse counting), regardless of the ambient temperature.

(The current temperature is 9C & generation has peaked at 3440kWh.)

Hi

The issue is the effect of the panels heating up over time. You state that you have 4kWp of panels and a 3.7Aurora inverter, however the energy graph provided is displaying in 15minute time-slices. The energy displayed in each time-slice could be the result of averaging fluctuating power over the 15 minutes or continuous stable generation. In the case of the data displayed, each 15 minute period is generating ~850Wh, which equates to averaging 3.4kW (0.85x4), which is below both the capacity of the panels and the inverter. It's also the case that with a 4kWp array and 4 15minute periods/Hr, you have the same multiplier (ie 4) and therefore the nominal equivalent of 1kWh potential for each 15minute period, therefore the system effectively produced 850W/kWp, or you could also say that the array was running at 85% of nominal capacity.

Unless there's an issue, such as the inverter de-rating due to high operating temperature, a 3.7 inverter (Aurora 3.6kW?) should not be capping generation at 3.4kW, therefore it's logical to conclude that it's not doing so, consequently it's also logical to conclude that it's simply the result of the panels operating at an elevated temperature.

HTH
Z

jrfarrim

This place really has some excellent contributors. I've spent the last week reading up on panels and I'm now ready to start getting some quotes. Any recommendations for Installers who cover Bury, Greater Manchester area?

Thanks

1961Nick

zeupater wrote: »

Hi

The issue is the effect of the panels heating up over time. You state that you have 4kWp of panels and a 3.7Aurora inverter, however the energy graph provided is displaying in 15minute time-slices. The energy displayed in each time-slice could be the result of averaging fluctuating power over the 15 minutes or continuous stable generation. In the case of the data displayed, each 15 minute period is generating ~850Wh, which equates to averaging 3.4kW (0.85x4), which is below both the capacity of the panels and the inverter. It's also the case that with a 4kWp array and 4 15minute periods/Hr, you have the same multiplier (ie 4) and therefore the nominal equivalent of 1kWh potential for each 15minute period, therefore the system effectively produced 850W/kWp, or you could also say that the array was running at 85% of nominal capacity.

Unless there's an issue, such as the inverter de-rating due to high operating temperature, a 3.7 inverter (Aurora 3.6kW?) should not be capping generation at 3.4kW, therefore it's logical to conclude that it's not doing so, consequently it's also logical to conclude that it's simply the result of the panels operating at an elevated temperature.

HTH
Z

For a 15 minute 0.86kW timeslice, generation has to be a continuous 3440kWh...ie the maximum.

0.86kW timeslices occur very frequently & over a full range of ambient temperature....probably 2C - 25C. That would appear to discount temperature as being the limiting factor. Trust me, it's the inverter & 3440kW is the maximum that reaches the meter - ever!

Whatever the effects of temperature are, they mainly occur somewhere between 4kW & 3.44kW.

Dave_Fowler

jrfarrim wrote: »

This place really has some excellent contributors. I've spent the last week reading up on panels and I'm now ready to start getting some quotes. Any recommendations for Installers who cover Bury, Greater Manchester area?

Thanks

Eco-Deal from Rochdale came all the way down to Bedfordshire to fit my panels. I've been very pleased with the results. They were a much smaller company back in 2012 and gave me a very competitive quotation. Since then they appear to have taken up the Green Deal and are promoting this on their website. I'm sure they would be happy to quote a price for someone just down the road from them with or without the Green Deal finance.

Dave F