Well I would say you should know all the skill sets of a BA and be able to speak to each one. A BA, at their core, is someone who can learn about a system (or multiple systems), someone who can work with teams of people from the operations to the technical people and they should know the ecosystem they are working in. These people have to, therefore, have some technical understanding, good technical writing, domain knowledge and teamwork skills. Some places have BAs work as pseudo project managers too...
Some things like technical writing you can learn from a course. Other things make more sense to learn on the job somewhere. All things considered, if you can show these traits you're in good shape.