Choosing a solar panel for the British weather

Steve_S · Oct 28, 2023

Johneb said:
Steve S, would you still consider shingled panels if full sun, no shading?

If the option sis available within a reasonable price difference MOST ABSOLUTELY !
Remember when the Talk About shading starts, that it includes cloud cover & low sun days as well.
When you have a string of 4 panels for example, and a single panel get's shade/shadow on even 1/4 of it, the whole strings output falls drastically. This is easily observable and repeatable... Go out and cover any "part" of a panel in a string and you will see it plain & simple on the power it generates.

Actually Andy @ Andy's Garage YT did a reasonable video showing teh differences and how the perc shingled panels took that without a blink. I think it was 4 months ago or so. People would not believe it till he showed that even covering one segment only reduced generation by the amount of that segment and not the whole panel.

Regardless of where someone is, clouds and other factors are always at play.
But what the hell do I know... I just design, build & install systems and more... now starting an ESS Battery Company (Q1-2024) here in Canada so, I'll just move along....

zanydroid · Oct 28, 2023

I agree completely on the effects of covering a panel (hard shade or non uniform light across a panel), but I fail to see how that applies to clouds which are much more diffuse.

EDIT: what cell types do better at low uniform light? And why (or a reference to where I can read up on the mechanism).

Urge38 · Oct 29, 2023

zanydroid said:
I agree completely on the effects of covering a panel (hard shade or non uniform light across a panel), but I fail to see how that applies to clouds which are much more diffuse.

EDIT: what cell types do better at low uniform light? And why (or a reference to where I can read up on the mechanism).

Living in the uk, and like most, needing more, free eclectic in the winter than the summer, I too Conclude low light levels are the evil. i.e. cloud cover etc

I am NOT winning,
BUT being born with dyslexia AND having a mounting of work ahead off me (how have I complied so much work !!??) can someone please just name a panel for me???

not loads of options, just pick one for low light conditions and link it plz.
I would really appreciate that if you don't mind.

zanydroid · Oct 29, 2023

You’re going to need to focus on help from domestic forum members if you just want a panel name since that depends on what is available locally. You also need to provide the roof geometry or whatever if there is a constraint.

For the MPPT you need to specify budget and other requirements like future expansion plans, whether you want it to communicate with XW ecosystem.

Partimewages · Oct 29, 2023

I find lots of information on shingled panels but very few for sale that specifically call out shingled.

Do they call them something different?

ShaneC · Oct 29, 2023

https://www.itstechnologies.shop/ worked great for me, was the cheapest around and good selection. I went with:
415W JA Solar Mono PERC Half-Cell MBB Black Frame Solar Panel £104 + vat × 6

New and I've seen them get good charge even though they are poorly angled (shed roof sadly).

Quattrohead · Oct 29, 2023

Just get the most amount of Watts for the least amount of pounds that will fit your needs. You're only talking about 1 or 2% difference overall I would guess.

Urge38 · Oct 29, 2023

slightly off topic

BUT can you conclude anything from the Voc of a panel ???

Ie, is higher better for cable voltage but worse because you need to have an adequate MPPT charger for the higher Voc

Steve_S · Oct 29, 2023

! CAUTION !
The different types & sizes of Solar Panels can make life miserable without care & caution.
VOC is a CRITICAL NUMBER ! There are 12V, 24V, 36V, 72V solar panels (common market) and commercial panels that can produce over 100Vdc !
The Panel Type & Size dictates that.

Depending on Solar Controller they all have limits for Voltage/Wattage/Amperage. A Higher Voltage MPPT may not always be prudent, same with lower voltage MPPT controllers.

Case in Point, I use Midnite Solar Classics.
My C-200 can take up to 200VDC and output 100A Charge to my bank. (8x 260W panels 4s2p)
My C-150 can take a Max of 150V and give me 90A of Charge. (6x Qcell 395W panels in 2s3p)

There is the lurking gotcha, especially with AIO's and their Hi Volt MPPT controllers.

SamDeleted · Oct 29, 2023

Urge38 said:
slightly off topic

BUT can you conclude anything from the Voc of a panel ???

Ie, is higher better for cable voltage but worse because you need to have an adequate MPPT charger for the higher Voc

Yes and no , it only really matters when it comes to sizing the array , figuring out series/parallel , keeping it max array voltage under max PV input of the MPPT

Urge38 · Oct 30, 2023

I have been doing a little you tube watching (as reading and being dyslexic don't go grate together) BUT reading/seeing between the lines,

I am swaying more to smaller panels, but more of them!!!??

what do you guys think???

it is heartbreaking when you watch a string of lager panels wired in series, drop the output watts due to one panel being obstructed.

I am liking the idea of more, smaller panels AND more, smaller charge controllers.

SamDeleted · Oct 30, 2023

Urge38 said:
it is heartbreaking when you watch a string of lager panels wired in series, drop the output watts due to one panel being obstructed.

I am liking the idea of more, smaller panels AND more, smaller charge controllers.

The only way to help that is with multiple strings of solar panels:

A) in parallel to one controller
B) each with its own controller
C) a mix of the two

Don't forget, each string has to hit about 70vmp to guarantee charging a 48v battery

SamDeleted · Oct 30, 2023

Urge38 said:
smaller charge controllers.

It's definitely a good option if you suffer shading ...... The issue is the price of a 48v charge controllers.

If you're interested here is my 48v set up for a shady area:

8x 425w Trina solar panel
42vmp/50voc/10amp
Wired in 2 series, 4 parallel
Output:
84vmp/100voc/40amps

Morningstar TriStar PWM 60a
PWM so less efficient

Many controllers have quite a low input amp rating (so you can't have panels in parallel), but tristar can handle upto a huge 60amps solar input

If you've got the budget you might look at the Tristar MPPT, very efficient and can still handle the amps

Tristar pwm:

Morningstar TriStar

These powerful tropicalised three-function PWM controllers provide reliable solar battery charging, load control or diversion regulation to divert excess power to a dump load for use in solar, wind or hydroelectric systems. (Two or more controllers may be used to provide multiple functions)...

www.windandsun.co.uk

TriStar mppt:

Morningstar TriStar MPPT

The industry-leading TriStar MPPT with TrakStar Technology is an advanced maximum power point tracking controller for larger off-grid photovoltaic (PV) energy systems up to 4.2kWp. An iconic design, TriStars have been proven in solar installations around the globe and remain the first choice for...

www.windandsun.co.uk

Both quite expensive but don't forget morningstar make grade A - top class equipment, up there with the best of them.

And you'd only have to buy one

Urge38 · Oct 31, 2023

My set up, is to power a workshop,
I am not always there.
I would hate to turn up, and find my entire string of panels have produed nothing, due to a fault, blown fuse etc etc etc

I was liking the idea, if one panel stops (for whatever reason) then the others would be working.
that is also a bit true with the worry of shading or cloud cover (to a lesser degree)

Good point about minimum Vmp to charge 48v

Urge38 · Oct 31, 2023

SamG340 said:
It's definitely a good option if you suffer shading ...... The issue is the price of a 48v charge controllers.

If you're interested here is my 48v set up for a shady area:

8x 425w Trina solar panel
42vmp/50voc/10amp
Wired in 2 series, 4 parallel
Output:
84vmp/100voc/40amps

Morningstar TriStar PWM 60a
PWM so less efficient

Many controllers have quite a low input amp rating (so you can't have panels in parallel), but tristar can handle upto a huge 60amps solar input

If you've got the budget you might look at the Tristar MPPT, very efficient and can still handle the amps

Tristar pwm:

Morningstar TriStar

These powerful tropicalised three-function PWM controllers provide reliable solar battery charging, load control or diversion regulation to divert excess power to a dump load for use in solar, wind or hydroelectric systems. (Two or more controllers may be used to provide multiple functions)...

www.windandsun.co.uk

TriStar mppt:

Morningstar TriStar MPPT

The industry-leading TriStar MPPT with TrakStar Technology is an advanced maximum power point tracking controller for larger off-grid photovoltaic (PV) energy systems up to 4.2kWp. An iconic design, TriStars have been proven in solar installations around the globe and remain the first choice for...

www.windandsun.co.uk

Both quite expensive but don't forget morningstar make grade A - top class equipment, up there with the best of them.

And you'd only have to buy one

I was leaning to Trina Vertex S+ 425w myself.

but I can only fit four for now!!! (might be able to double that with some roof strengthening)

Many thanks for your set up and the details

Urge38 · Oct 31, 2023

SamG340 said:
8x 425w Trina solar panel
42vmp/50voc/10amp
Wired in 2 series, 4 parallel
Output:
84vmp/100voc/40amps

just wondering!!! is that not 6 panels then??? 2 plus 4 = ???
also, the max wattage of the 60amp is 3200 watts, if you have 8x425 you are over the limit!!!

SamDeleted · Oct 31, 2023

Urge38 said:
just wondering!!! is that not 6 panels then??? 2 plus 4 = ???
also, the max wattage of the 60amp is 3200 watts, if you have 8x425 you are over the limit!!!

2s4p equals 8 panels total

4 parallel strings of 2 panels each

Complicated I know ??

SamDeleted · Oct 31, 2023

Urge38 said:
also, the max wattage of the 60amp is 3200 watts, if you have 8x425 you are over the limit!!!

It's called 'over-paneling' the charge controller

MPPTs can do it happily sometimes up to 150%

PWM not so much ...

Morningstar have a system design/sizing app , I have filled it out , they are happy with up to 10x trina 425w/50voc, in 2s5p

- that's on both the mppt and PWM models

String Calculator - Morningstar Corporation

+

string-calculator.morningstarcorp.com

SamDeleted · Oct 31, 2023

Urge38 said:
I would hate to turn up, and find my entire string of panels have produed nothing, due to a fault, blown fuse etc etc etc

Yes very good point there, get an LPG Geno ?

SamDeleted · Oct 31, 2023

SamG340 said:
2s4p equals 8 panels total

4 parallel strings a 2 panels in each series

Complicated I know ??

2s4p diagram

Screenshot_2023-10-31-13-32-42-084-edit_com.android.chrome.jpg

Choosing a solar panel for the British weather

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