You can check the battery life by gently pressing your finger on the Ellie logo at the bottom right corner of the lid for about 8-10 seconds. It is a cap-touch button, so it works by feeling a change in capacitance. That being said, if you press down on it hard, it may not work.
Ten lights will appear, each representing 10% of the battery. The green lights represent the percent of the battery that is charged. The red lights represent the percent of the battery that is not charged.