Today I went out and had 2 batteries to charge when I got home - one was almost depleted and one was about 20% down. Charge the more full one first and then plugged the more depleted one in. After about 10 minutes I start hearing a squeaky sound, something akin to a moving part that needs oiling. I'm sticking my ear next to everything - it's not the laptop fan, it's not the fan on the battery charger (which isn't on). Finally I bend down and it's coming from the power adapter block. I pick it up and it's hot and the light is red instead of green - and it's squealing inside. I immediately unplug it and let it cool down. I'm contacting support but in the meantime has anyone experienced this at all? Thankfully I've got 2 other fully charged batteries so I can fly some more this afternoon, but I'm hesitant to use the charger again.