The article on Click2Houston has some advice from the Red Cross on how to conserve and charge your mobile phone battery during a disaster:
Conserve phone battery:
- Leave an outgoing message on your voicemail that includes your status and location, and then turn off your phone.
- Use SMS text messaging, which will go through cellular networks easier than a voice call.
- Turn on “flight mode,” which keeps your phone from transmitting or receiving and greatly extends battery life (SMS will not work on this setting)
- Disable or turn off apps that you’re not actively using to save the battery power