What is the battery life of Watch Generation 2?

5 days of extended battery life.
• Activity tracking mode: 5 days tracking.
• Full recharge in about 120 minutes.

 Please note: the battery life is, however, also affected by the type of usage, number of repeated measurements, incoming messages and display usage. 

For example: if the 24h monitoring sensor is constantly on then the battery will consequently last less.

What is the difference between Watch 2 and Watch Lite SE devices?