My sons science project

System

My son is doing a science project about solar energy and I have a question about how much power my solar panel is producing. We made a home made solar panel with some nearly new solar cells. My meter read 12 volts and about 1 amp. What I need to know is how does that convert to watt hours? Does it create 12 watts per hour? Or is there some other formula I need to figure with. I want to know how it relates to my home power usage of kilowatt hours.

niel

Re: My sons science project

essentially yes, it is 12 watts per hour as it takes time into account, but more specifically it is always referenced to 1 hour. in your example if it did this for 2 hours it would be 12v x 1a x 2hrs = 24wh. this would've been the total power that would've been produced if it was all in 1 hour. if your pv delivered power as you stated and it was for a half an hour it would be 12v x 1a x .5hrs = 6wh

icarus

Re: My sons science project

Using 12 volts as an example can sometimes confuse the numbers.

Remember VoltsXAmps=Watts. WattXTime=Watt/hours,,, or watt minutes or Kilowatt hours for that matter.

So in the case of 12 volts X 1 Amp = 12 watt X 1 hour would be 1 Watt/hour,,, or 1 amp/hour @ 12 vdc.

Just to illustrate let say for example your panel was putting out 2amp at 14.6 volts volts. You would then have 14.6X2=29.2 watts.

In order to measure power produced or consumed,,it has to be stated with a time component. 100 watts means little,, but 100 watt over 10 hours equals 1kwh.

So you panel has the POTENTIAL to put out,, say 1 amp or 12 watts,,, but the meaningful measure is then watt hours,,, or extensions of watt hours. (Kwh or watt/minutes etc.)

Often times with batteries, (and solar panels) useful measurements are stated in amp/hours@ X voltage. It is stating the same reality,,, just differently,,, just to confuse us!

Good luck with the kids and the projects. Sounds like a worthy endeavor.

Tony

niel

Re: My sons science project

"So in the case of 12 volts X 1 Amp = 12 watt X 1 hour would be 1 Watt/hour,,, or 1 amp/hour @ 12 vdc."

warning, error.
oops, that should've read, "So in the case of 12 volts X 1 Amp = 12 watt X 1 hour would be 12 Watt/hours,,, or 1 amp/hour @ 12 vdc."

System2

Re: My sons science project

Thanks for the info.
So how many hours of sunlight does northern Arizona average? I have seen anywhere between 6 to 8.5 hours.

icarus

Re: My sons science project

Here is a link to a layman's solar sizing tool that can give you real life numbers for solar performance: http://rredc.nrel.gov/solar/codes_algs/PVWATTS/version2/

Remember,,, your mileage will vary!

Tony