I had the PD35, but the micro USB broke, so I ended up buying a kit off Amazon that came with a charger and 3 18650s for like $20. It was awesome cause I'd have 4 charged batteries at any time and just swap them out like you said. I lost that one in the woods hunting. The PS36R comes with an ARB-L21-5000 battery that dwarfs the 18650. I haven't checked if there is a charger for it yet.