This guide will illustrate for you how to replace the battery from a Sanyo Katana Eclipse X.
Press the battery release button located on the back of the phone.
With the button depressed, pull down on the battery protector to remove it from the phone.
Slide a thin object under the white tab located on the bottom of the battery and carefully lift away from the phone.
The battery should now be free of the phone.
Align the copper receptors on the back of your battery so the phone's copper receptors are touching the battery terminals.
Using your thumb, apply gentle pressure to the battery until it clicks into place.
Take the phone’s back casing and set it over the battery.
Apply gentle pressure, pushing towards the top of the phone until your hear a click.