most of the reason they put out less is the connections. i have not experienced significant loss in output with mine, even the crazed one. i got 2 of them because the former owners said they had deteriorated.. rofl... NOT--- they put out exactly what they did when they were purchased new. awesome. just clean connections .
has a diode in it-- with a good regulator
a diode is redundant. yes a regulator is needed for any over 1 amp--i melted a battery
with one 1 amp panel. (long ago--i am smart now.)