Product Managers and Business Analysts are different

Basically, Product Managers work at companies that create software that
sells in a market. They are outward facing. They know they need to seek out
customers and find out what they need to make their lives better. Product
Managers are concerned with competitor products and change outside the
company.
In contrast, Business Analysts work at companies which develop software for
their own internal use, or on specific developments for other companies
which will be used internally. Thus they are normally found in corporate IT
departments and external service provider (ESP) companies.
Business Analysts look inwards, they look at the operations and needs inside
a company. They know exactly who their users are, indeed, in some cases
there may only be one user. When Business Analysts look outside the
company they are looking at suppliers as alternatives to development not as
competitors in the market.