I am not sure of your exact setup, and I do not qualify as an expert on this, however, there have been several failures reported due to problems with the rectifiers overheating during prolonged periods of high wind. I would overbuild the rectifier, and use the largest heat sink I could get my hands on. I took what I thought was a large heatsink (10inches by 5.5 inches with about 1.25"fins) out West with me earlier this year and was surprised to learn from the Dan's that it would be marginal at best for a large 12V machine, although suitable for a 48V machine of the same size where the current would be reduced to 1/4th for the same power. Derate the total amps that each rectifier can handle when parallelling them, I'm not sure what a proper percent would be, but 30% would seem relatively safe to me. While the voltage drop across each diode goes up with increased current, which tends to even out the current across the parallelled rectifiers, this may not be an exactly even split across the diodes due to slight manufactuing differences between otherwise identical units. For that reason you should derate them when connected in parallel. Rich Hagen