Use as many or as few bananas as you would like: I used about three.
1 or 2 lemons
Preheat oven (or toaster oven for small batches) to 175 - 200º F
-Slice bananas in thin slices no larger than 1/4 in.
-Place banana slices on a parchment lined baking sheet as close as possible without touching each other
-Squeeze or brush lemon juice on banana slices and place your baking sheet in the oven
-Bake the bananas for an 1hr - 1hr 45min, depending on your desired consistency
-After removing the bananas from the oven, let the chips cool on the baking sheet- they may be slightly gooey, but as they cool they will harden
For a more standard "banana chip" texture, you can coat the bananas in a sugar syrup (boiled sugar and water) or you can deep fry banana slices, which is another standard method of making banana chips.
*At this temperature the oven will act more as dehydrator than an oven, hence the long baking time. Depending on how thick you slice the bananas and how crispy you want the chips to be, your baking times may vary. I recommend taking out a few slices at intervals to test the consistency.