I had one go dim in a ryobi lithium 18v work light and the switch and stuff work but the module is very dim. Also one led on the inside doesnt work as well, the thing is stuck in moonlight mode.
Never had any of my modules get hot as i have one in a maglite 2d using six eneloops in series @8.4V, then a two eneloops in a 2c and they all get room temp but nothing to be considered warm or even hot.
I'm contacting him and going to get another of course but have to let others know if interested in this setup as its a hit or miss as i have all my others work awesome and i have used them a lot longer like three months or so.
Otherwise the other i have a ryobi nicd 18, the thing is crazy bright as its atleast equal to a 2Million candle power spot light without the throw of course but this thing is a beast.