What power are my solar panels?

[Tim Good]

My rigid panel is 1200 x 670 and the regulator shows it as kicking out about 4 - 4.5amps when it is sunny.

I can't find any documentation on it so unsure of the wattage. How can I tell? It isn't just a case of 4x12 I'm sure.

Purpose being is that the panel is about 10 years old and although working fine, I'm sure by today's standards I might be able to get something significantly more powerful for the site.

 

[catalac08]

Your panel is the same size as my 80W panels which also put out about 4-4.5amps when it is sunny.

 

[Tim Good]

Your panel is the same size as my 80W panels which also put out about 4-4.5amps when it is sunny.

Thanks. Ok so I found this type on a few caravanning sites and they are exactly the same size as mine to the mm and are 120w. Assuming mine are 80w like yours then it appears as though by today's standards I'd gain 40w for a swap job.

https://www.norwichcamping.co.uk/pr...gy-120watt-solar-panel-kit-voltage-regulator/

A 1/3rd more is fairly significant. Suppose I just need to determine if they are marine grade.

 

[VicMallows]

I agree your existing panel sounds like 80w (peak rating) and seems to be performing as one might expect.

I am not aware of any recent massive leaps in technology which would account for the 1/3rd claimed output increase in the panel you are considering. The price though is certainly well over the going rate.

 

[Huttoft]

http://www.ebay.co.uk/itm/351093050672?_trksid=p2060778.m1438.l2649&ssPageName=STRK:MEBIDX:IT

There are quite a lot of the above sized panels selling on Ebay. The OP's are physically 120% larger than the advertised panel, so perhaps a new panel of the size of his/her's might expect to give 120% more output than that advertised. This might mean 120w.
Good luck.

 

[NOHOH]

Unfortunately.....It doesn`t work like some are appearing to suggest. Any quoted `rating` will be theoretical...and derived from the maximum output voltage....er...around 21.7 volts........giving theoretically around 6 amps....max..... So...a rule of thumb estimate of what to expect from any solar panel in terms of amps is to divide the wattage figure by 20

 

[charles_reed]

Rather than relying upon posters' guesses it might be an idea to get some facts.

There have been considerable advances in PV panel output over the last 3 years, a quick visit to the kyocera site will banish that prejudice. It has come at some cost in power-loss from shading. However it's more like 20% than 30%.
As we don't know the age or manufacturer of the OP's current panel it's difficult to more than guess at its rated output but, based upon the BP solar I had it's between 70-85 watts.
The closest comparable PV panel on Kyocera's site is 1500 x 670 mm and has a rated output of 140 watts.
http://www.kyocerasolar.com/assets/001/5520.pdf
I'd definitely steer clear of EBay products, mainly because they are of unknown provenance, sold by people who have little knowledge and even less reputation to lose.

 

[Tim Good]

Rather than relying upon posters' guesses it might be an idea to get some facts. I'd definitely steer clear of EBay products, mainly because they are of unknown provenance, sold by people who have little knowledge and even less reputation to lose.

Thanks for that. They look good. However considering I don't leave for me big trip till late next year I may wait till then as things might have progressed further in terms of the size / efficiently ratio. In terms of size I don't want to mess about fitting a new frame to the goal posts to I'll upgrade if I can find one exactly the same width and bolt it straight on.

 

[Boreades]

Something like this 150W panel
http://renytek.co.uk/p/219/150w-monocrystalline-solar-panel-with-bosch-solar-cells

Is the same width I think?
Dimensions 1340 x 670 x 35mm

 

[JumbleDuck]

My rigid panel is 1200 x 670 and the regulator shows it as kicking out about 4 - 4.5amps when it is sunny.

As others have said, the power output is generally quoted at around 20V, so assuming you don;t have a fancy MPPT controller, you are getting about 80 - 90W out of yours. That will be significantly less than the maximum possible output (Sahara sun directly over horizontal panel) so I expect yours to have been 100W or even 120W originally.

I wouldn't worry about buying cheap on eBay, by the way, as there aren't that many makers of cells and panels around.

 

[whiteoaks7]

My rigid panel is 1200 x 670 and the regulator shows it as kicking out about 4 - 4.5amps when it is sunny.

I agree: about 120W providing they are crystalline and not amorphous. It works like this 1.2m x 0.67m = 0.8 m^2 (presumably these are overall dims not the sum of all the cells). The rating is given at 1000W/m^2 so 804W of solar power falls on that area, but the conversion efficiency for a crystalline panel is somewhat less than 20%, (so guessing at 15% for an antique about 120W nominal at the max power point. On a good day and depending on your installation you can reliably get 60% of that delivered to your battery so you should get 72W so divide this by the charging voltage say 13V and you see 5.5Amps so your numbers are in the right ballpark. This requires a panel pointing at the sun at solar noon. There currently is no better technology than crystalline ones since the academic thrust is for lower cost per Watt and that makes for less efficiency and thus bigger panels. Personally I bought cheap and am prepared to replace them in ten years when they fade a bit. January PBO might help a bit.