Advanced Smelter

Advanced Smelter is an addon for carts which can automatically smelt items. It works similar to the Smelter, but has a few additions:

Toggle-able production output - a player can set where to store the output (chests, engine slots, different module slots).
Production limitation - a player can set the amount of items required to smelt. Can be set to infinite, too.

Recipe

By installing this with a chest, wood cutter, and coal engine; you make a minecart that if used correctly will never run out of energy.