You don't need to turn it off. Just do 'lock screen and keys' and set the timeouts of the wifi and screen to 10 min max or so. Because when the screen and wifi are off it will stay charged for days.
Strange as it may seem, turning it on and off drains the battery faster than using 'lock screen and keys'.

Also close any programs/services that are known to be power hungry, and/or might try to re-open the network connection. I know Microb especialy with Flash animations running, uses quite some cpu power . Also turn off the SSH server service when installed. OMWeather connects to the internet for updates by default.