Gateway TM 5150 User Manual page 52

Built-in battery meter
The battery you received with your notebook has a battery meter built into
it. To check the status using the battery meter, remove the battery from the
battery pack bay (see "To remove the battery pack" on Page 47) and turn it
over.
Press in on the circle indicated by the hand icon. The battery meter below
the icon lights up to indicate the percentage of battery power available.
50 Using Your Gateway Solo™ 5150 Multimedia Notebook