The most important part, if using the c40 in diversion mode, is to size the dump correctly.
I have used and set up many c40's. Most for PV applications, and in charger mode, but probably 6 or 7 in diversion mode with wind, and have caught every one of them on fire from over voltage. They are too slow to respond, and this is why we have moved on to either building a controller to suit the specific needs, or using another brand that has much lower hysteresis.
If using sealed batteries, the over voltage could really ruin your day (and your bank). Flooded cells can take a little more abuse.