Hey Dad!.. welcome to the forum!
you shouldn't have to power down as these batteries go all day and then some.
You will most likely have much better voicemail service if you stay up.
Some alternatives may be to:
1. Mute your phone if you don't want to be bothered.
2. Leave it on the charger when you would normally have it powered down as apparently you don't need it then anyway.
3. Get a car charger... it will charge from almost dead in a little over an hour.
4. Get an extended battery that will give almost double battery capacity.
You can check that out here.
You may not know how to check your battery level so you may be nervous as to how much is left... you can download an app that gives a continuous readout..."I like the one called batterylife..... or go to.
settings---->scroll to the bottom to "about phone"---->status----> second one from the top will show your battery status.
settings---->scroll to the bottom to "about phone"---->"battery use" will give you a breakdown of what is eating your battery.