I don't know whether to think that the #1's are under powered or my #4 is over powered. Unless I purposely try to hide wood in a corner, I always end up with ash and not charcoal.
I don't think the SI#1 is under powered. when using the "Smoking Times, Temps. and wood as a guide...I'm right in the ballpark. Just a thought....do you know if the heating elements are the same distance from the wood box on the different models?
I find the 400 w element, in the #1, to work quite well, for the size of the smoker. The higher wattage, in the other models, is only due to the length of the element, and the volume it has to heat. I don't know about the #4 (yet), but the other models are the same distance between the element and smoke box floor. I think seeing ash only, in the #4, makes perfect sense. That big element gets really hot, during heat-up, so it stands to reason that the wood will burn faster.