Choosing a solar panel for the British weather

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

Urge38 · Oct 31, 2023

SamG340 said:
2s4p diagram

View attachment 175357

I like drawings lol

that is SO MUCH easier to understand lol

I am getting sold on the Tristar, looks a good bit of kit.
ill probably end up going for siz panels but possibly the 635W as I will only be getting six

SamDeleted · Oct 31, 2023

Urge38 said:
I like drawings lol

that is SO MUCH easier to understand lol

I am getting sold on the Tristar, looks a good bit of kit.
ill probably end up going for siz panels but possibly the 635W as I will only be getting six

A picture paints 1,000 words ?

635w sound great , but can be tricky to mount if you're singlehanded... they are big and heavy !

I'm not sure on their specs, but remember it's important to get the solar voltage level right , especially if you're going for the PWM model .

Feel free to post up if you need help with the maths

Urge38 · Nov 1, 2023

my bad

meant to type 435w not 635w

Sam, did you set all the parameters in the Tristar yourself???
I noticed that there is a dip switch setting for L-16, I am guessing that's Lithium 16cells,

if so, that will get me in the right ballpark to start off, as my four rack batteries are 16 cells.

SamDeleted · Nov 1, 2023

Urge38 said:
my bad

meant to type 435w not 635w

Sam, did you set all the parameters in the Tristar yourself???
I noticed that there is a dip switch setting for L-16, I am guessing that's Lithium 16cells,

if so, that will get me in the right ballpark to start off, as my four rack batteries are 16 cells.

Tristars are very much lithium compatible, but I'm not sure if any of the preset profiles are suitable .

If you set the DIP switches to the 'user defined' setting and wire up to a PC with morningstars app (MSview) then you can then adjust any & all settings to get it perfect for your LiFePo4 batteries

I do not know exactly what settings are correct for LiFePo4, others may be able to help .... also morningstar customer service would offer help if needed

Can Morningstar Solar Charge Controllers Charge Lithium Batteries? - Morningstar Corporation

Our TriStar MPPT, TriStar (PWM), ProStar MPPT, ProStar (Gen3), and SunSaver MPPT are Morningstar’s top solar charge controllers for lithium batteries.

www.morningstarcorp.com

SamDeleted · Nov 1, 2023

Urge38 said:
I noticed that there is a dip switch setting for L-16, I am guessing that's Lithium 16cells,

I think L-16 are flooded lead acid ?

This mentions possible BMS compatibility issues

Morningstar Best Practices By Battery Chemistry - Morningstar Corporation

Learn useful information about Factory Presets or Custom Setup for use with the latest battery chemistries and technologies.

www.morningstarcorp.com

Again I am no lithium battery expert, hopefully others will help !

SamDeleted · Nov 1, 2023

@Urge38

Search results for query: Tristar LiFePo4

diysolarforum.com

SamDeleted · Nov 1, 2023

@MisterSandals sorry to tag you in, can you advise about lithium compatibility with the morningstar TriStars please?

Urge38 · Nov 1, 2023

Thanks for all your help SamG340

MisterSandals · Nov 1, 2023

SamG340 said:
@MisterSandals sorry to tag you in, can you advise about lithium compatibility with the morningstar TriStars please?

Lithium works great using settings in custom profile from Morningstar.
Here is all the info I have.

Morningstar reprograming for Lithium

I have two Morningstar SunSaver MPPT controllers one of which is used on our teardrop trailer. I bought the SunSaver about 14 years ago as it was the only one that would handle the high voltage from a used grid tie panel. The high voltage panel means we get usable current when it is shaded and...

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