Solar Panel Output??

Hello Nobby, I would have thought that that was about right . 7.5 over say 6 or 7 hours of daylight gives 45 or 52 amps which is not bad.

Regards

Mark

Nobby, do you get only 7.5 from BOTH panels wired in parallel?
Amps = watts over volts, in your case 80/12= 6.5 approx X 2 = 13 amps.
Result depends upon strength of sun & angle and length(resistance) in wires
to where you measured the amps & maybe the accuracy of the ampmeter.
My 60w (5amp) solarex has NEVER got near to 5 amps. 4 has been about the best & often much lower.
If there is a shadow over even the smallest corner of it the output drops dramatically.
I understand that later models/types dont do this.

What voltage does it supply?

Power = Voltage * Current

So if it is providing 12V:
12 * 7.5 = 90W

So if you do get 12V from it I'd be hppy.

It just puzzles me that you do all the sums and you should get 9.5amp ( which is in the specification sheet), but in reality I am only getting 7.6 max.(As per my multimetre) As stated have them in full sun, facing north, heavy duty cable etc, etc. I realise that I'm still getting enough to run my set up but why do they say you get "X" and you actually get "X" - something(in my case 2amp)??

Nobby

Kyocera info KC80.
Max V = 16.9
Max A = 4.73
watts = 79.937.
This max performance. I have 2 x KC80. Very difficult to get max output. Still good setup though.

Hope this helps.

Regards

Solar panels are rated to an industry standard in a controlled enviroment. They are subject to a brief flash of light of some makeup at I think 25c. What this boils down to is that in the real world you don't get what they say....great!
I have a 55 watt BP on the garden shed keeping a number of batteries alive. I get nearly 3 amps tops, usually 2.5

Nobby

Three possible explainations given to me were:

1). Solar panel output is affected by the cell operating temperature. Panels are rated at a nominal temperature of 25 degrees Celcius. The output of a solar panel can be expected to vary by 2.5% for every 5 degrees variation in temperature. As the temperature increases, the output decreases. I've proven this by throwing a bucket of cold water over the panels on a hot day and seen the current climb.

2). Panels are typically rated at around 16V. I've been told that if we could run everything off them at 16V rather than 12V, they would operate more efficiently. Dunno how true this is ?

3). Is your load taking all of the current ? If you are charging a battery and that battery is fully charged, you may not see the full current.

Food for thought anyway. I use and efficiency of 75% of the stated output when doing my calculations.

Regards

If it does what you want who cares. All these things are done @ optimum conditions & we don't get that in the bush do we?

Hi Nobby,
I have heard if you inprove their reflective amount ie,shinny foil,gal tin sheet it actually improves output by reflecting more light onto the panels..also the higher they are mounted the better,Hope this helps.
All The Best In Health And Wealth
Jeffrey (AKA JD)

Gidday Nobby. It's that 20% inefficieny I spoke about over on OL, as explained to me by a solar panel techo. The manufacturer's specs are based on a certain (cool) panel temp in high intensity sunlight with full current load ignoring all current losses through wiring, heat losses etc.

You can discount these optimum specs by at least 20% for the real world.

Glad to hear however, that the two panels are delivering sufficient for your needs.

Have a look at this for a really good explanation of the proper use of solar panels. It coveres the matching of panels to loads, including batteries, and explains "where the power goes"

http://www.windsun.com/ChargeControls/PPT.htm