A few things to remember. A good, well cared for battery doesn't usually just burst into flames.
So making sure you don't ding, drop, or overdischarge the packs is the starting point. Then sort out any cells that don't behave right. That's your primary safety. Wes is charging safe, but I would get something more fire resistant than wood to put on top of the desk. A piece of cement tile backer board or a large tile is not that expensive.
After that, I'd move that smoker just a few more inches from the bench. Look above too, in case the lid won't stay on it. Try to put the smoker where it wont ignite something else nearby if he lid comes off. You can live through smoking up your garage, but lighting other things in the garage is to be avoided at all costs. You might not make it out of the house if it burns in the night.
Smoke detector in the room is good, but you won't hear it from the bedroom.
The best suggestion already said, ASAP, get a faster charger so you don't have to go to bed with it still running a charge. It's not good to sleep while charging, just like its not good to leave a candle burning in the house and go to bed.
