What are Bypass Diode, Blocking Diode and Isolation Diode?
What is the difference between a bypass diode, a blocking diode and an isolation diode?
A blocking diode is used to prevent batteries from "leaking" current. You do this by placing the diode on the positive line between the module and the battery.
A bypass diode is wired in parallel with a module to divert current around the module in the event of shading. Bypass diodes are pre-wired in some modules and usually sufficient unless the module has a higher voltage.
Isolation diodes prevent the loss of current in the event that one string of modules in the array fails.