# Solar cells

#### assuc

hi,
I am working on a small solar cell project for which i bought two small solar cells panels of 6volt each producing current of 5.263milli ampere in combination.
I want to know that how can i calculate the values of solar cells output in kwh, on the output i have placed two bulbs of 3 volts in series and connected solar cells in parallel so as to increase the current.
Or any other method of calculating values and please recommend a graphical value too.
All answers will be highly appreciated.

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#### physicsofme

I'm relatively new to physics, (17 going to college physics next year), but I believe you have everything you need to understand the output in Kilowatts per hour.

Kilowatts= (Amperes * Volts)/1000

Kw= (.005263 * 18)/1000

Kw= .000094734

^here above i converted the milli amperes into regular amperes then combined the voltages of both the 6 volt solar panels and the two 3 volt bulb. Then to top it off, I divided by 1000 for converting watts into kilowatts. Then for kilowatts to kilowatts per hour, multiply by 1 hr and you still get the same number as an output, or .000094734KwH.

That's for the combined system I assumed you wanted, otherwise you wouldn't have needed the bulbs.

Again, I'm VERY new to just physics in general, but I try to help since there are no replies yet :/ And I just did basic equations...

#### assuc

I'm relatively new to physics, (17 going to college physics next year), but I believe you have everything you need to understand the output in Kilowatts per hour.

Kilowatts= (Amperes * Volts)/1000

Kw= (.005263 * 18)/1000

Kw= .000094734

^here above i converted the milli amperes into regular amperes then combined the voltages of both the 6 volt solar panels and the two 3 volt bulb. Then to top it off, I divided by 1000 for converting watts into kilowatts. Then for kilowatts to kilowatts per hour, multiply by 1 hr and you still get the same number as an output, or .000094734KwH.

That's for the combined system I assumed you wanted, otherwise you wouldn't have needed the bulbs.

Again, I'm VERY new to just physics in general, but I try to help since there are no replies yet :/ And I just did basic equations...
But the confusion is that you have combined the output voltage of each bulb while taking out the kilowatts... as i am only concerned about the power solar cells are producing not the bulbs, as to best of my knowledge we will multiply the voltage value of solar cells and that will be 6Volts (as both solar panels are in parallel so the voltage remains same in parallel combination).
Do correct me if i am wrong.!!
thanks again

#### davenn

Gold Member
just a couple of comments :)

@ physicsofme...
always use the standard SI units when doing formula, do any conversions at the end
so always use W = V * A etc, else you may get into strife with more complex calculations :)

Also, your globe voltages should NOT have been included, thats giving false info.
As assuc said its the power generated by the panels that is being calculated. The globes are not supplying voltage to the system, in your calc they incorrectly are.

@assuc....
The 6V and 5.263 mA is probably the open circuit (no load) ratings. Under load, the output voltage is going to drop a volt or so. check the paper work for the panel and see if it comments on no load and loaded ratings :)

cheers
Dave

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