OK ... request for dimensions of Solar Panels

[Refueler]

We have all looked online and at sales sites .. whether Chinese / German / UK / whatever and TBH - many just do not add up in terms of panel size to Watts out claimed.

What I am asking (it will really help me and I am sure many others) - is not for Brand names or sellers ... but the physical dimensions vs what should be the Watts quote for that panel. The best source of such info - is of course actual users ...

So how about it guys and gals ?

Simple replies of :

Length x Width x Flex or rigid .... Nice summer day watts capability ...

I suggest we do not need novels about Caribbean .... Isle of Sky ..... and how they are mounted etc... just some data to help plebs like me decide how and where to fit. I realise that type of panel can also affect its size vs watts ... but lets try and keep this simple - easy to use to sift through the sales pages of panels ...

My 38 has a panel that is showing signs of age ... and I am considering swapping it out - moving it to less demanding use on my older smaller boat ... the area it covers can accommodate a slightly larger panel ... nice to know what I can fit instead.

 

[fredrussell]

Just look on a decent/trusted seller’s site and use their figures. Eg photonic universe, Renogy, Epever etc and ignore purveyors of exaggerated or ‘mis-described’ junk on eBay.

 

[Refueler]

Just look on a decent/trusted seller’s site and use their figures. Eg photonic universe, Renogy, Epever etc and ignore purveyors of exaggerated or ‘mis-described’ junk on eBay.

Fred ... not everyone lives in UK etc. - my aim was to get numbers ..... not brand names as I already posted.

Users also have info based on real use ... which I trust more than any seller - regardless of who seller is.

 

[rotrax]

We used Craig Solar.

2X 200W rigid panels, each 100cmx100cm. EPever 30AMP controller.

Mounted on the pilothouse roof, only slight shadowing from the twin backstays or boom under some conditions.

Since fitting 12th May '22, when aboard we run two large refrigerators and a Dometic 40 litre freezer box 24/7.

Batteries not been charged except by main engine alternator or the solar since that date.

Even on dull days batteries reach float. Four or five consecutive dull or rainy days they drop to 12,7-12.8V. Lower if we use the inverter for cooking.

Well pleased, I got EXACTLY what I hoped for.

Monocrystaline rigids is the way to go IMHO.

 

[dunedin]

These Sunbeam Nordic panels are excellent and claim to be optimised for northern climates like the Baltic.
We fitted two of these panels on our sprayhood, supplied by SVB in Germany who I am sure would easily supply to you - SUNBEAM NORDIC Solar Panel / 54 W only 139,95 € | SVB

If you drill down into the excellent technical specs from Sunbeam this will give you very good and reliable data on panel sizes available and realistic power ratings - far safer than the various eBay adverts

 

[AntarcticPilot]

The size to power relationship is fairly variable, depending on both the technology and the implementation. Also, the efficiency of solar panels is increasing steadily. I don't think there is a reliable formula; all you can do is look at the websites of reliable suppliers (some named above; I have been happy with Photonics Universe). I recognise you aren't in the UK, but the suppliers named should give you accurate numbers to work with, even if you end up buying through another channel. Figures from boat owners aren't comparable because every installation is different; for example, I have 200 w fitted, but if be surprised if I ever get much more that 100 w because of shading etc.

Note that power figures given are maxima, for the highest possible insolation values (sun overhead with a clear sky). That level of insolation is never reached in Northern Europe; just for example, my rooftop installation is rated at 2.2 kW, but never generates more than 2 kW. I am in East Anglia, which maps of expected returns from solar panels show as being about as good as can be achieved in the UK. Of course, you are at a somewhat higher latitude, so I'd guess you'll be doing well to get 85% of the rated value.

Incidentally, the Chinese are the world leaders in this technology, so don't be put off by Chinese suppliers. AFAIK, European brands may be assembled in the EU but the cells themselves mostly come from China.

 

[Baggywrinkle]

Panels are made of individual solar cells joined together, depending on how many cells the panel supplier has chosen to put on his panel, and how they are arranged, will determine the dimensions of the panel, as will the type and location of the junction box and how much free space has been left around the cells.

This means that for flexible panels there are a plethora of available dimensions and outputs.

My experience on both my boat and my camper van is that you need to shop around to find a combination of output (more is always better) and dimensions that will fit in the space you have available - there is no magic formular, and there are no "standard sizes" for flexible panels.

I would go for ETFE coated panels as they are more hardwearing and buy from a reputable source, they will fail at some point, and a good supplier will just swap it out at no cost.

Try to avoid mixing panels that have different output voltages and/or currents.

 

[KevinV]

My experience on both my boat and my camper van is that you need to shop around to find a combination of output (more is always better) and dimensions that will fit in the space you have available - there is no magic formular, and there are no "standard sizes" for flexible panels.

This is my recent experience too - I simply opted for the largest (in Watts) panel I could fit in the space available, allowing for the fact that some panels have more "border" around the actual cells (I cut a bit of border off mine). It was a bit of a task searching through all the options to find what worked for me, but I suppose the good thing about the lack of standardisation is that there are many options to fit many applications. I chose a (to me) no-name brand because of fit, it happened to bit quite cheap too - it's in an easy location to change if it turns out to be rubbish, but so far so good.

 

[noelex]

What I am asking (it will really help me and I am sure many others) - is not for Brand names or sellers ... but the physical dimensions vs what should be the Watts quote for that panel. The best source of such info - is of course actual users ...

Reputable panels undergo testing under standardised conditions that are identical for all manufacturers. The peak output should be the claimed "watts" the panel is sold as producing.

If the panels are quality products, installation is well done and the panels are subject to good solar insolation in a shade free location then users should find that they meet these specifications or very close to these numbers at least briefly. There is little difference between panels of the same published wattage, as they have all been rated under identical test conditions. The exception is cheap "no name" panels where the numbers have simply been dreamed up by the manufacturer.

In exceptional conditions it is possible to exceed the rated wattage.

There will be variations in the size of panels needed to produce the same number of watts. More efficient (and expensive) panels can produce the same energy in a smaller physical size. This efficiency is easy to calculate from the published specifications. Around 15-17% is typical. The very best panels are around 21-22%. The smaller physical footprint of more efficient panels is helpful in yacht installations where space is limited, but in terms of energy production the number of watts is the most important number, although there are some variations in shade and low light performance between different panels that does not effect the peak output and therefore it is not assed in the basic specifications.

 

[Trident]

New panels are now reaching 23% efficient so will be smaller than those that are only 16-18% efficient from a couple of years back as noted above. The type of panel, type of material used etc will all be variable

What you are trying to do simply doesn't work. As an example I am this week changing 4 x 260w panels bought 5 years ago for the roof of my boat which are exactly the same size as the 4 new 320w panels - so 20% better capacity in the same size.

If I could go 8cm wider - which is not a lot but with 4 means over a foot more width which I can't do - I could jump from 320w to 400w - now 8cm over 1.6m does work out to enough extra sq m to add 80w but the makers of the bigger panels use even more efficient cells .

Good makers such as Renogy (who I supply for full disclosure ) are UL certified - which is very stringent checking on all they do and claim with actual live testing done. Most of the bog names like Renogy, Victron, Maxeon etc all have full EU wide distribution so no issue getting it in Europe.

 

[noelex]

The highest output I remember seeing while sailing in UK waters was from a Sunpower 335w panel that produced 344w. The outright best has been in the Caribbean where we recorded (briefly) an exceptional 429w from the same panel.

However, these brief peak output numbers are not particularly relevant. The average numbers or total daily production is more important.

This panel is 1.558m x 1.046m so has an efficiency of 20.6% for the published 335w rating. 100x 335/ (1.556x1.046 x1000) = 20.6%.

It is worth calculating the actual effeciency of any panel you might purchase. The 1000 in the above formular is from the 1000w/m2 which is STC test conditions and the 100 is so the result is in percentage form. Simplified the formula is rated wattage of the panel divided by area of the panel x10 (in square m).

 

[TSB240]

Adobe Acrobat.
If you are commited to flexible panels these are some typical dimensions and outputs. I used an earlier version of this brand and found that that they performed as specified for 2 years maximum. I have since given up with deck mounted flexible panels as they are never in the best place for either maximum performance or minimising damage. They restrict dinghy and other on deck storage and are liable to water ingress.

I eventually found that two 80 watt narrow flexible panels fitted nicely inside a stowed mainsail stack pack.
12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine
These were more than capable of recharging batteries fully between weekends coastal sailing and consistently kept my fridge running when at anchor. They can easily be stored under bunks whilst sailing and tied down onto a boom cover.
The weakness of flexible mounted panels is the connection of the output cable. and integrity of the potted connection including the diode. This is usually the first point of failure and reduced output caused by water ingress and corrosion.

 

[Aja]

We have all looked online and at sales sites .. whether Chinese / German / UK / whatever and TBH - many just do not add up in terms of panel size to Watts out claimed.

What I am asking (it will really help me and I am sure many others) - is not for Brand names or sellers ... but the physical dimensions vs what should be the Watts quote for that panel. The best source of such info - is of course actual users ...

So how about it guys and gals ?

Simple replies of :

Length x Width x Flex or rigid .... Nice summer day watts capability ...

I suggest we do not need novels about Caribbean .... Isle of Sky ..... and how they are mounted etc... just some data to help plebs like me decide how and where to fit. I realise that type of panel can also affect its size vs watts ... but lets try and keep this simple - easy to use to sift through the sales pages of panels ...

My 38 has a panel that is showing signs of age ... and I am considering swapping it out - moving it to less demanding use on my older smaller boat ... the area it covers can accommodate a slightly larger panel ... nice to know what I can fit instead.

What is the largest (WxL) panel you can fit, then compare all the similar sized panels from the suppliers mentioned. I don't think you can search for output/sq metre.

 

[fredrussell]

Fred ... not everyone lives in UK etc. - my aim was to get numbers ..... not brand names as I already posted.

Users also have info based on real use ... which I trust more than any seller - regardless of who seller is.

That’s the point I’m making really - you can trust some sellers. This is the internet age - the last thing a reputable seller wants is to be ‘called out’ on their numbers.

 

[noelex]

That’s the point I’m making really - you can trust some sellers. This is the internet age - the last thing a reputable seller wants is to be ‘called out’ on their numbers.

Yes, I agree solar panel specifications are one of the few marine products that have to be tested under identical conditions regardless of the manufacturer (providing the manufacturer produces a quality name brand product). Watts are watts.

Keep in mind that the specifications only address the peak performance.

When looking at the specifications also consider the temperature coefficient and the power tolerance. These factors have some impact on performance in the real world, although the difference is not huge.

Flexible solar panels can have poor durability so the details of the output warranty can be important.

 

[B27]

What is the largest (WxL) panel you can fit, then compare all the similar sized panels from the suppliers mentioned. I don't think you can search for output/sq metre.

Current (sic) state of the art is about 230 watts of electricity per square metre,
That's nominal power under full sun which is about 1kW/sqm 'standard conditions'.

 

[Aja]

Current (sic) state of the art is about 230 watts of electricity per square metre,
That's nominal power under full sun which is about 1kW/sqm 'standard conditions'.

Is that available as a search item anywhere?

 

[noelex]

Is that available as a search item anywhere?

You can calculate the efficiency of any solar panel simply by using the forrulae in post #11. The calculations are simple from the data provided by the retailer. 23% is state of the art for domestic/industrial panels.

 

[William_H]

Hi Nigel I understand your question and uncertainty. I have been looking at new PV panels for household roof top. The latest panels appear to be of similar size to my 10 year old panels but seem to be claimed twice or more the wattage. Now I understand there have been huge improvements in PV efficiency over that time. I perceive that you want a flexible panel for new boat. Would you be getting latest technology? Would be interesting to see area versus watts of what is available and compare that to claims for large PV panels for domestic use. Actual watts delivered by my inverter with so called 1500w array is at best around 1200 watts summer midday. (at 32 S)
Anyway good luck with your quest and I hope to see what you find. ol'will

 

[PetiteFleur]

I used Photonic Universe flexible ETFE panels which keep my 3 batteries fully charged. Good service.