For every sport mode you can choose one the predefined battery modes: Performance, Endurance and Ultra. By default, Performance will be activated. You can also create a custom battery mode. When you defined a custom battery mode, this mode will be used by default.
During multisport exercises the same logic applies:
How do I get the most out of the battery modes?
How does GPS accuracy in battery mode impact the tracking of my exercise?
What affects the accuracy of the battery life estimation?
Can I set or adjust battery modes in the Suunto app or Suunto Movescount?
How do sport mode settings in Suunto Movescount affect the battery mode settings in Suunto 9?