How to save your mobile phone’s battery life? - Use Avast Battery Saver. Our free app from Google Play optimizes phone settings using ‘Smart profiles’ which activate automatically based on time, location, and battery level. This saves up to 20% on one charge. Get it free, bit.ly/1GHkODN - Avoid full discharges and charge the battery more often between uses. - Limit exposure to extreme temperatures, especially heat. Don’t leave your phone in a hot car. Room temperature is best.