Ive got a 358L (~95 gallon) chest freezer which I am wanting to use as my fermentation chamber. Ive read about using a light bulb to buffer the chilling of the freezer as my temp controller doesn't have increments short enough (less than one minute) to allow it to maintain an even temperature around where I want it to be. What wattage would I be best to start with do you think? I'm thinking I will just have the bulb kick in at the same time as the freezer on the same circuit to simply buffer the effect of the freezers cooling/freezing cycle. Does that sound the easiest way to go? The insulation is good so I don't expect it to cycle on and off very regularly, its holding 5C as a fridge at the minute and clicks on for at most 5mins every 60 to 90mins.
How about a brewbelt? I haven't read anything about the light bulb. My freezer produced a lot of condensation when used as a fermentation chamber. I don't know if I would trust any electrical connections in there. I'm sure I'm overlooking something though.
You don't want the freezer to cycle too often IMHO. Even if the freezer cycles every 20-30 minutes and fluctuates temp a few degrees, the 5 gal of brew will keep a steady temp. Not sure I understand the your concerns or question. People usually add a light bulb as a heat sourcewhen needing to add a touch of heat in cold winter climates.
Even if the controller has a 5 degree buffer the fermenter will not change that much, you only need a heat source if the outside temperature is very cold for long periods and it affects the temp inside the freezer. If that is the case you can use a 60w bulb and leave it on all the time, just be sure to cover the carboy.