Note: This cheat requires editing game files; do at your own risk. To obtain infinite battery energy, first navigate to your Outlast settings: C:\Users\\Documents\my games\Outlast\OLGame\Config. Look for OLgame.ini within that folder and open it with Notepad or a similar text-editing program, then search for "bat" (without the quotation marks) and that search should lead to a series of lines in the file that appears about as follows:
Update the setting of the second and third lines so that they read "true" instead of "false" and save the file. You will then have infinite battery energy.
Note: Making a back-up first is recommended. Navigate to C:\Users\offic_000\Documents\My Games\Outlast\OLGame\Config and you will see a file named OLEnemy. Open it and then make some changes. As you scroll down, you'll find things under titles such as and . These are enemy titles that contain codes such as NrmAttackNormalDamage=51, NrmAttackThrowDamage=51, HardAttackNormalDamage=101, HardAttackThrowDamage=101, and so forth. Change those values from their current numbers to 0. There are several to change, so the process could take quite some time. Make sure that you only change digits that relate to the values specified above. The end result once you change all appropriate entries is that no enemies will be able to inflict any damage.