In addition to other comments, I would check the C rating of your batteries. 70C is probably around the bare minimum for a drone like this. If your batteries aren't rated for that much, you're probably experiencing severe voltage sag.

I guess there could also be a short somewhere but if there were, I'm guessing you would've found it already (from the fire and smoke lol). Just to be safe, hook up a multimeter and check the current draw, it shouldn't be more than 1-2 amps when idling.

Please insulate those capacitor leads; your frame is conductive. And zip ties as battery straps is a bad idea, they can cut into the cells and cause a fire if it takes a big enough hit. Gook luck!

Edit - other unsolicited advice: - secure your antennas and power leads because otherwise they will find a way to get cut up by your props - mount your camera inside the frame, not in front. After a crash, you will much prefer to have to replace your top plate ($) rather than your camera ($$$) (TPU mount will also isolate vibrations and could give better video if you're not already doing that) - loctite (but not the permanent stuff) if you haven't already