1.All buyers are using same fan. total buyers are more than 200. there are 2 or 3 fans of bad quality. I sent them a new fan. But this fan works perfect with my controllers in general. If your fan does have quality problem, I can send you a new one
2.SS box. I can not design SS box to suit all batteries. Someone simply uses his car battery. By no means my SS box can suit a car battery. You should discard your 1.3 ah lead battery and change to a 2 a.h Li-ion battery
About temperature accuracy
My controller is one factor, your smoker is an important factor too.
Just think heavy mass ceramic smoker, double walls smokers like stumps and backwoods and vikiing, and single wall of 1.5 mm carbon steel of Brinkmann.
Certainly the best is MY smoker of gravity feed burner.
My gravity feed burner is DIFFERENT from backwoods, stumps,,viiking.,
My burner its self is reverse flow.