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This is a very nice build. One thing that I would do, is to have the door open to the outward instead of inward. One reason is for fire purposes as is in the convention for commercial buildings. The other is for the shedding of rain. If the door opens inwardly, that allows water to seep under the door and onto the floor. Opening outwardly greatly reduces this tendency.
This is a nice treatise on "machine" drying tomatoes. Actual "sun" drying is drying in the sun. I consider using a machine to be safer and less labor intensive.
One must be careful to make sure that the battery that you are trying to charge is a "lithium-ion" battery. Those lithium "non-rechargeable" batteries can explode violently if you try to charge them. I know!
Baby oil is mineral oil and fragrance. That is easy to find.