Calculating Current from Solar Panel Voltage

[jabers]

Is there a way to determine the amount of current that can be drawn from a solar panel based on the voltage?

Say you have a 100 Watt solar panel. If you measure 24 volts and then later 20 volts can you say anything about the current being produced?

P = IV but if there is no load connected then you are getting the open circuit voltage right?

I want to measure the voltage and say I can power a device that draws say 50 Watts or two devices that draw 30 watts each.I don't mean predict future current just at the instant the voltage is measured.

 

[berkeman]

Is there a way to determine the amount of current that can be drawn from a solar panel based on the voltage?

Say you have a 100 Watt solar panel. If you measure 24 volts and then later 20 volts can you say anything about the current being produced?

P = IV but if there is no load connected then you are getting the open circuit voltage right?

I want to measure the voltage and say I can power a device that draws say 50 Watts or two devices that draw 30 watts each.I don't mean predict future current just at the instant the voltage is measured.

Have you read about "maximum power point" tracking for solar panels?

http://en.wikipedia.org/wiki/Maximum_power_point_tracking