> Keep in mind that with series-connected panels, the total voltage is the = sum > of the individual panel voltages, but the current through the string is > limited to the current of the least-illuminated panel. This may be what t= he I had considered the current would be limited but that implies that the shaded panel's resistance is greater than zero. I accept that the panels do have a reistance, but if they are partially illuminated and generating some power them I suspect that resistance would be low. I have some panels, I should go and measure OC Voltage, CC Current and Non illuminated Resistance. Also perhaps voltage across a panel connected to perhaps a 20 ohm resistor and measure the current and voltage at various illuminations and plot. Justin --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .