I cannot understand why doubling the amount of solar panels gives only a few percent increase in total amount of power.
Here are the test results of a single 10-cell panel: Single solar panel efficiency tests http://imageshack.us/a/img43/6561/nlgd.png
Here are the test results of two panels connected in series:
And here are the test results of two panels connected in parallel:
My expectations were:
- to see the voltage of 9.3V under load in serial connection, yet I've got 4.3
- to see the current of 5.2A under load in parallel connection, yet I've got 2.6
- to see the wattage doubled in both serial and parallel connection, yet I've got 10%,20%
Can someone explain the reasons behind such a weirdness?
The tests we repeated with the two different multimeters swapped in places to measure voltage and amperage.
The tests were conducted 1.5 - 1.0 hour before the noon, on a clear sky conditions, so there's a bias of few percent in measurements due to increase solar elevation angle.