What is the battery on Dahan tower crane?

The battery is used to assist parking.

Tower crane, referred to as tower crane for short, is a kind of rotating crane with movable arm installed on the upper part of towering tower, which originated in western Europe. According to the form of boom, it can be divided into horizontal type and pressure bar type, with large working space.

Used for vertical and horizontal transportation of materials and installation of building components in building construction.