Bananas - too many - so how can I preserve them?
You don't mention what variety of banana you have access to. There is a host of banana varieties and they all have different characteristics in regard to flavor and texture.  



I will assume that you are referring to the Cavendish variety that is ubiquitous in the west.  



Cavendish bananas, when ripe, are very fragile. They go mushy easily and oxidize quickly. Before they are ripe they are more starchy but relatively flavorless with kind of grassy overtones.

Drying them is easy and great if you like eating a lot of banana chips. Recipes are easy to find. You want to use bananas that are slightly under ripe. If they are fully ripe they get leathery instead of drying crisp. Some recipes will call for spraying or tossing them in acid or other mixtures to improve the color or flavor. Obviously, living in a dry climate will help a lot making the drying process much faster and so reduce the chance of mold.

You don't often see banana preserves (chunks of fruit bottled in a syrup) because the ripe fruit falls apart when cooked and the under ripe fruit doesn't have a strong or pleasant enough flavor.
Instead, an option that is used often in SE Asia where there is a huge variety of bananas is banana jam. This is more like what I would call a fruit butter. The bananas are pureed and cooked with sugar and sometimes pectin and then bottled. Sometimes chunks of fruit are left but they are much more tender than your typical preserves. It tastes good and will keep almost forever. If you haven't bottled before, the bottling process is more involved than drying. It is easy to find recipes. Many of them will include lime juice or other acids to reduce the browning. Often spices are added which will vary according to the local cuisine.



The strangest preservable banana application I have seen was Filipino banana ketchup. Not bad but I can't imagine using enough of the stuff to preserve any quantity of fruit.

While writing this post I discovered that banana ketchup is made everywhere bananas are more common than tomatoes. It looks like banana ketchup from other cuisines has a greater ratio of banana and is appropriately yellow.