Power Dissipation of Schottky Diode
Am I using the right approach?? Any suggestions here


Maybe you should consider the standard MOSFET circuit (but modified) that acts as a very low volt drop diode i.e. it protects a circuit from reverse polarity but turns the MOSFET on so that forward volt drop is barely a few milli volts. The basic circuit is this: -



+Vin is where you would connect the solar panel and +Vout is the battery connection. If you add a bipolar transistor and base resistor you get this: -



From a quick simulation, the BJT turns off the MOSFET when the battery voltage exceeds the SP voltage by about 730 mV (R3 is 10k not 100k). Between the voltages being equal and the battery being 730 mV higher there will be some hundreds of mA flowing back to the panel. However, if you are trying to protect the panels from the wrong battery being put in place (i.e. 24V instead of 12V) then it should do the trick.

It's just an idea and not proven other than by a quick sim. Caveat emptor!!