Winter panel performance - yes I know the sun is lower etc.

[Steve Fractals]

I'm sure this has been asked many times but can't find any specific posts. Just wanted others experiences of panel production in winter.

Been live for just over a week, currently I only have 1.5KW of panels mounted with another 750w's to add soon. The highest I've seen the inverter report is briefly 700w's but mostly between 400-650w when the sun is shining, is this about normal for winter production with panels facing south at 35 degrees in the UK? I expect somewhere around half max power is about right for winter but just wanted to check.

 

[MisterSandals]

Yea, it’s bleak in December.

Solar Irradiance Calculator

www.solarelectricityhandbook.com

So your daily production should be about 1.5kWh. (1500W x 1.05h).

I do not know your exact location or panel angle, use your info if different.

 

[DThames]

You don't say where in the UK but Greenwich is about 50 degrees latitude, so your panels should be about 50 degrees, ideally. So you will be hurt from that angle difference. I am at 35 degrees with my panels at 35 degrees. My last good day was 3 Dec. I was peaking at 8900w. Other times of the year, 9200-9500 peaks are more common. I have 10800 watts of panels on micro-inverters.

 

[SeaGal]

Mine are East-West so not quite the same, but about 30% peak sounds about right

 

[Mattb4]

Never hurts to double check connections and do various voltage and current measurements. My experience is my panels still produce good wattage in Winter if in full sun. They just rarely see it at this time of year.

 

[Steve Fractals]

You don't say where in the UK but Greenwich is about 50 degrees latitude, so your panels should be about 50 degrees, ideally. So you will be hurt from that angle difference. I am at 35 degrees with my panels at 35 degrees. My last good day was 3 Dec. I was peaking at 8900w. Other times of the year, 9200-9500 peaks are more common. I have 10800 watts of panels on micro-inverters.

Yes I went for 35 degrees as my research says that's the optimum for all year round for my area which is Manchester UK. 50ish for summer and 21ish for winter but given my panels are fixed I just went for what was reported to be the optimum year round.

Thanks.

 

[DThames]

Yes I went for 35 degrees as my research says that's the optimum for all year round for my area which is Manchester UK. 50ish for summer and 21ish for winter but given my panels are fixed I just went for what was reported to be the optimum year round.

Thanks.

My references to angles were from horizontal.

 

[45North]

Nice job!
But between your latitude and weather, I'm not surprised.
Conventional wisdom is to set the angle same as your latitude for year-round if fixed. +/- 15 deg if you're adjusting seasonally.
Remove snow, if any.

 

[littleharbor2]

These numbers should be taken from horizontal, not vertical. That being said your winter setting should be the higher number, not the smaller one.

 

[45North]

Measured from horizontal: so steeper in winter.
Edit: Manchester is almost at 55N. So 55 year round, 70 winter, 40 summer.

 

[Steve Fractals]

These numbers should be taken from horizontal, not vertical. That being said your winter setting should be the higher number, not the smaller one.

Yes I took my angle from horizontal not vertical, thanks for the info.

 

[Steve Fractals]

Now I'm starting to get confused again lol. Most sites I checked said the optimum angle for fixed panels in my area of Manchester, UK is 35 +-5 from horizonal so I built my solar porch to have 35 from horizon but after reading some comments I'm confused as to if that should be 35 from flat horizonal or from upright vertical.

So mine are 35 from flat horizon or 55 from vertical, is that right or should I have reversed?

 

[DThames]

Now I'm starting to get confused again lol. Most sites I checked said the optimum angle for fixed panels in my area of Manchester, UK is 35 +-5 from horizonal so I built my solar porch to have 35 from horizon but after reading some comments I'm confused as to if that should be 35 from flat horizonal or from upright vertical.

So mine are 35 from flat horizon or 55 from vertical, is that right or should I have reversed?

This site is reference vertical, shows 36 degrees for Manchester UK.

PVWatts is reference horizontal. Many of us in the US use this site. My power company wants to see numbers from PVWatts when you do a grid tie agreement prepositional.

 

[ianganderton]

Now I'm starting to get confused again lol. Most sites I checked said the optimum angle for fixed panels in my area of Manchester, UK is 35 +-5 from horizonal so I built my solar porch to have 35 from horizon but after reading some comments I'm confused as to if that should be 35 from flat horizonal or from upright vertical.

So mine are 35 from flat horizon or 55 from vertical, is that right or should I have reversed?

Here are the angles these guys give for optimum performance in Manchester along with solar hours for 36deg from vertical (optimum year round)

Solar Irradiance Calculator

www.solarelectricityhandbook.com

Gawd damn the uk weather and irradiance is rough isn’t it!! Bear in mind international average is 5hrs a day

 

[TomC4306]

Every inclinometer app I've tried measures from horizontal.

 

[mvonw]

I'm in Northern New Hampshire and I'm experiencing my first winter with my 12kwp array. I went with bifacials (not because I'm smart, they were the only ones available), and I've been pulling around 9500 watts for about 3.5 hours each day this week (sunny days only). A little snow cover and the cold really make these things produce. My panels are mounted at 45 Degrees, and they seem to shed snow quickly, but we've yet to hit real winter yet. It's interesting to see what other people experience.

 

[sunshine_eggo]

I'm sure this has been asked many times but can't find any specific posts. Just wanted others experiences of panel production in winter.

Been live for just over a week, currently I only have 1.5KW of panels mounted with another 750w's to add soon. The highest I've seen the inverter report is briefly 700w's but mostly between 400-650w when the sun is shining, is this about normal for winter production with panels facing south at 35 degrees in the UK? I expect somewhere around half max power is about right for winter but just wanted to check.

Is there sun in the UK? I thought that was just a rumor.

 

[Steve Fractals]

See the site above suggests 36 from vertical but other sites say from horizontal as below with many others also saying 35 from horizontal, if these solar suppliers can't agree then how the hell are we supposed to get the correct answer.

Tilt and Orientation and Solar Energy​

https://www.viridiansolar.co.uk › resources-1-3-tilt-and...



The position that maximises the energy collected by a solar panel in the UK is facing south and tilted at an angle of 35 degrees from the horizontal.

Best Angle for Solar Panels in the UK and Beyond

Which is the best angle for solar panels? Compare the performance of solar panel tilt and orientation on roofs in the UK & around the world.

blog.spiritenergy.co.uk

 

[SamDeleted]

Manchester UK

It's grim up north , no wonder your not making much power

 

[SamDeleted]

Gawd damn the uk weather and irradiance is rough isn’t it!! Bear in mind international average is 5hrs a day

Hahahaha

It hardly matters which angle you click on that calculator, December/January are still RUBBISH