Add all the ingredients except raisins to a blender and blend into a smooth mixture. Add raisins then pulse for a while to properly mix into a batter.
Line the dehydrator trays with sheets. Scoop a tablespoonful of batter and drop on the sheet. Repeat with remaining mixture.
Place in dehydrator and dry at 115°F (46°C) for 10 hours or until the outside of the cookie is crunchy. Remove from the sheet and turn cookies over; return to dehydrator tray and dry for another 6 hours or until the cookies are crunchy but slightly soft inside.
Serve warm. Store the raw banana oat cookies in the fridge or in an air- tight container.