it has to be a pretty big parasitic loss if you can lose all your power in 45 minutes after driving.

I have killed my battery several times with the radio staying on in about an hour(while I was in the car), as well as the trunk light or dome being on.

When you power down the car and close everything are you sure those things are shutting off? A sticking switch in the door, or trunk lid could leave either on, but then dislodge and work fine for a period of time, and be an intermittent problem like this. The only other thing I can think of with a 45 minute kill time would be headlights or DRL. They operate off a relay system that could stick as well turning the on/off if the relay is bad.

I am going with the thought on big systems since you said 45 minutes. To me this is if there are no issue with your alternator or wiring to the alternator. Even a loose ground on the engine could result in symptom like a bad battery not starting the car intermittently but still run the accessory stuff inside.