No start, No crank???

[wd13]

Hey guys, need some help. Couple days ago I was installing an XM radio in my truck. Had it in the shop with the door open and the dome light on for probably 6hrs. Got ready to start it and.....CLICK Battery gauge showed good voltage though. No biggie. I put the charger on for 10mins and it fired right up. Tonight (3days later) I drive it into town which is 25 miles away. Shut the truck off. Go back out to start it...CLICK. Call a friend to jump me and all is well again except the door ajar light stays on for 5 mins or so. So what could be causing either problem??? Haven't tested the batteries yet as I attributed it to the dome light the 1st time, but this time??? Also the gauge reads good again and the truck is starting fine.