What are some small lithium battery manufacturers located in Central America?

Probably because they are closer to were they are getting the raw materials for manufacture . It’s the same reason why many of the worlds electronics come from sections of China , the resources and supply of parts from other manufactures are there . It cost more money when you have to ship the parts or materials across vast amounts of distance . If the manufacture can be close to a hub were everything is or by the place were something is made it costs less .