To dry bananas in a dehydrator, cut them into slices, and let them dry for 10 to 24 hours in the dehydrator. To help keep the banana peel from contaminating the inside, wash the peel first.
After peeling the banana, cut it into thin slices. Coat the slices with lemon juice to help prevent browning while they are dehydrating. Put them on trays, and place inside the dehydrator. Make sure that they are in a thin layer and that no banana slices touch each other. Put the dehydrator on medium heat, and dry them for 10 to 24 hours. When they are done, the slices are dry and crispy, like chips. Store them in plastic bags or storage containers.