It might have to do with the 1.25 NEC thing.
390w would have about 390/130 x 8.2 = 24.6 amps aimed at high sun with PWM and batt v under 13.5v. IV curve says a little less amps above 13.5v till the big drop at 15v.
So if you expected 25 amps you should get a controller rated for 1.25 x 25 = 31.25
My Solar30 doesn't seem to give the panel watt limit. It says panel voltage limit is 48V and the "rated working current" is 30 amps
My MPPT 20 amp Eco-Worthy says its Voc limit is 42 or 45 volts (EDIT now they say 50v on their website specs!! Means it can do two 12s in series.) depending which list you read, and its max panel wattage is 300w-12v or 600w-24v.
300/130 x 8.2 = 19 amps so that doesn't work for the 1.25 margin, but it is MPPT and might therefore clip its amps so the margin is not required. I know it has a 25 amp fuse on its circuit board so that would be one limit! (had to change that when I made some sparks one time)
There was something funny that came up about the Blue Sky controllers having an operating amps less than the named size of the controller in their owner's manual. Can't remember the details.
