No cooling fan that I noticed. I must admit I only used this charger twice, both times I was charging sets of brand new (never charged before) batteries, and the directions said to charge them for 24 hours the first time. So I did. The charger light went out around 30 min, I guess it trickeled after that. By the 24 hour mark everything was pretty cool. At the 30 minute or so mark both the charger and the batts were warm to the touch, but by no means hot, or to hot to touch.