# charging circuit help

#### klugerm

Joined Dec 21, 2011
5
I would like to build a simple charging circuit where I can collect light using solar panels (small panels) and store the energy. I would then like to measure the amount of energy collected. I was thinking of hooking up the panels to a capacitor and measuring the voltage at various points in time to see how much energy has been collected. Is it that simple or is there more to it?

#### kwso

Joined Jan 3, 2012
2
Negative.

You may think about what happen if the solar panel is replaced by a battery.

#### jimkeith

Joined Oct 26, 2011
540
As an experiment, this is possible--only use a very small PV panel and a very large capacitor so that it does not charge so quickly that you cannot obtain measurements. Set it up for a charge time of about 10 minutes.

Remember the useful relationship: IT = CV
I = current in amps (constant current)
T = elapsed time in seconds
V = volts

Plot Voltage and current vs time on an Excel Spreadsheet Graph

ε = CV²/2

Plot energy vs time

Plot relative efficiency vs output voltage