I wish I knew. If you find something, please post it. I'm recently in too. Looks like a solid performer.
Best guess I can come up with is that these chinese solar plays are volatile, and there probably many factors beyond my comprehension that figure into the volatility.
I was eyeing CSIQ and SPWRA very closely a while back. The two stocks had identical price. Bought seasick on a dip; of course SPWRA then took off and seasick stayed flat or dropped a little.