Really cheap and simple charcoal farm

Power gearbox on top, might need to switch rotation depending on your power input. Top chest is for logs of any kind. if you use multiple logs youll need to use an item filter on the lower left funnel for extra logs in case you need more, if not destroy it and let it just be charcoal. The funnel on the right needs to be charcoal. lava in front of the fan with a sign in front of that to prevent leaking but still blasting.