I was looking at the mounting of the rectifiers and wondering if the heat sinking is sufficient.  I took what I thought was a pretty large aluminum heat sink (about 12.5 by 26 centimeters about a centimeter thick base with about 3cm fins on that) out by the Dan's in the spring and DanB told me that it would be insufficient for a 12V roughly 3meter machine, but maybe ok for a 48V machine because the amps are so much less.  I can't tell for sure, but it looks like your rectifiers are mounted on a thin aluminum box and I'm wondering if that will be sufficient in windy weather.