I agree with BobH127. You can have any size pile of charcoal and it should not affect temperature much. I cut my teeth learning to plug air leaks on an ECB barrel smoker. Once I had modified the firebox the smoker ran up over 450 degrees on the first try...with no water. But I had air leaks aplenty. Worked on the side door to get it tight. Using a light bulb at night I moved it around the outside seams while peering down into the smoker looking for light. I did find some air leaks. After much effort bending metal along the lip of the fire pan I got the temp down to 330 degrees and so I knew there was still some air leaks. Next I hung that light bulb down inside the smoker at night and crawled around the base of the smoker and found some more air leaks. Finally, I bought some tape stove gasket via ACE online and using stove adhesive I reduced most of the air leaks to a manageable level. I had fabricated an air damper valve or slider valve to regulate intake air. That made a big difference. I was able to easily get the smoker to cruise at 220, but the damper was almost closed to maintain that temperature. That means there is still the possibility of some air leaks, but how much I do not know. ( I did use a good long probe temperature gage).
What I did learn was that a vertical ECB barrel smoker cruising at 220 degrees with a fully loaded firebox will run all night. Water evap is much slower at 220 than at higher temps, but I still had to add water one time. I had made a 2 & 1/2 inch hole near the center of the cover lid and adapted a metal flag pole base from Home Depot as an exhaust. This allowed me to look down into the smoker with the water pan removed to look at the fire. Only a very small glow was to be seen and only in a small area of the loaded charcoal pan. That observation explained to me what the reality was of a 220 degree burn. A 220 degree fire is a very small fire and control of the air is what controls the size of the fire. So. To reach that 220 degree burn in a large pile of charcoal means you have tight control of the air. To me, getting control of the intake air is the whole game in operating a smoker. That vertical ECB barrel smoker was a real challenge getting it under control. Here is a web site of a fellow who did a classy mod job to accomplish air control of that smoker:
http://home.comcast.ent/~day_trippr/smoker_mods.htm Your browser security controls may not allow you to click on it. If not, copy and paste.
I am letting my ECB barrel smoker go at a garage sale. In it's place I have bought the ECB two door cabinet smoker and it has air leaks aplenty. Mainly, the two doors are huge air leaks in this rig. I plan to remove the stock hinges and install some small gate hinges to get the two doors to center properly. Also will attempt to install tape stove gasket around both door frames. There is way too much vent work in this stove. Like the fellow above I may plug the upper two side vents for just one vent on top of the stove with an exhaust pipe type of port....using another flag pole base...if I can find one again. I will permanently close one of the side vents at the base of the smoker. This smoker is somewhat flimsy. I wish the metal box was stronger, but I like the concept of this smoker and its ease of use. The price was an attraction as well. My needs are for a small smoker. My wife and my neighborhood relatives are not fond of smoker meats...apparently. So, the size of the smoker is about right for me. With the grill wok fire pan mounted closer to the floor of the smoker there will be plenty of room for anything I want to throw in there. Once I have this smoker fully dressed out I will post a photo. My goal is to be able to keep a 220 degree fire running all night on one load. Ha. We will see.