2011 Ford Transit Connect won’t start after sitting

Bought 2011 transit connect. Great little van for my business. mileage 17,000. Runs good but if it sits for 3 or more days it will not start. Has to be jumped. The battery is good. Cant figure it out. Thought maybe it was the door sensors so made sure all were closed firmly. Only thing that I noticed is the radio will come on, with key out no accessories on…??
Have any ideas…

Yes, the radio is at fault. Is it a Ford radio or an aftermarket one? If it is a Ford radio, for some reason it thinks the car is on or in accessory so it is “awake” and drawing more current and draining your battery. If it is an aftermarket radio, it may be wired incorrectly but it is doing the same thing. Disconnect the radio and check to see if the truck draws the battery down in 3 days. If not, replace the radio. Or put a switch in to disconnect the radio every time you park it.