Pro trick : you can watch movies on Flixzone. Been using them for watching all kinds of movies these days.

@Joel Brandon yup, I've been watching on flixzone} for years myself :)

You should check voltages on the charger and the batteries first. Although if the LED on the charger is red when it's not plugged into the board, and it's identical to the way this one is supposed to work, then it might have something to do with the charger. Couldn't tell you anything for certain, but if you have a multimeter available, start with checking voltages.

I realize that I could have probably been more clear in the video. At the time, what I was thinking and what I was saying made sense to me, although I realize it may have been a bit confusing to others, so I apologize. I'll try to explain a bit better below: What I believe killed the power supply is that the two MOSFETs shorting basically became the equivalent of just placing a wire directly across the output of the power supply. The MOSFETs are for driving the motor and they have nothing to do with the actual charging circuit. When everything is connected together, the power supply, battery pack, and controller boards are all connected in parallel, so any of those components that shorts across the positive and negative are going to be a short across everything else. The protection circuitry inside the battery pack kept a dangerous condition from happening because it practically disconnected the battery pack cells from everything else when it sensed too much current being drawn from its output due to the shorted FETs. The only feedback the charger/power supply actually has is a current sense resistor built directly into it. The way it appears to work, from what I could tell, is that it senses the voltage across that resistor using the LM358 op amp. If it's above a certain level, it indicates through the LED that it's still charging. The charger has no idea if what's connected to the output is an actual battery pack, or a resistor of some sort, so as long as it senses current draw, it just keeps trying to supply it. What you mentioned is probably not far from what has actually happened with some of these units that have caught on fire. I haven't seen one that has burned up to know for certain, and this is the only one of these units that I have actually played with. If I were to guess, I'd say that in the cases where they have caught on fire, either the battery protection circuit failed, didn't cutoff because the current being drawn wasn't high enough, or the design of the charging circuit is just poor. The protection board inside the battery pack probably has a pretty high cutoff current set to be able to handle the high load placed on it by the motor when the board is being used. I'm sure it wouldn't take too much amperage to melt some wires and make everything else catch on fire. I hope this helps explain things some!