What current (or power if that's more handy) rating do you need?

Number 1 best seller on Amazon.

You did specify 30V - is that the actual voltage you need or did you round up? A 36 cell solar module is fairly common - you'll have an open circuit voltage of about 22V in that configuration, less after the panel heats up.

Second best seller on Amazon.Its becoming more common to claim "12V panel" as a way of saying "panels intended to charge 12V batteries" - it has nothing to do with the actual open circuit voltage of the panel.

To be honest, if you can't easily get replacements, I wouldn't go cheap on this component.