Does this look right? Excuse the amateur drawing skills. Obviously, I would not hook up the PV panel intentionally but in case of an MPP failure, I think this would be the circuit.
NOTE: Edited to remove image with incorrect wiring diagram. See the diagram by @BradCagle in the following comments.
NOTE: Edited to remove image with incorrect wiring diagram. See the diagram by @BradCagle in the following comments.
Last edited: