Thanks for the info. I will check the open circuit voltage.
The max voltage isn't listed anywhere in the specs or installation or operating manual for the prostar. As a matter of fact you have to put in "max panel voltage" in the search of the ws, "max input voltage" or "max solar input" won't do it. THEN you get the message
"Do not charge a 12 Volt battery with a 24 V solar panel."
Seems like that should at least be in the manual. Maybe on the front page in big letters.
It's been a while since high school electronics but it seems like if I put a resistor inline between the panel and the controller to reduce it from 33v down to 18v it should work. I'll loose some amps but so be it. As you said I need to measure the OCV before I know how much resistance to add.
