Originally Posted by Crashdamage
That's not good. Power usage for standby and idle should be very low, like 5% or less each. Probably should contact your service provider.
Linux user #266351. Android since v1.0
That being said OP, I'm compelled to ask: how strong is the cellular signal where you are using the handset? Is it struggling to maintain a signal, or are you at/near full bars?