Where did you find that Mould King brick?
I've got some experience with CADA, I own 3 bricks and all my colleagues also have some. I replaced CADA brick batteries with slightly better "nonames". I also tested it with my chinese Buggy Motors and it seems that it works fine with one, but I think it would blow up with two working at the same time. Stock CADA batteries gave us 2 - 3 minutes of constant drifting in the woods with small buggy motor equiped car. It's not much, but I will test new batteries and I hope for 5 minutes at least.
Can someone post here photo of CADA brick electronics? I'm interested in how small PCB soldered to the original batteries is connected to the main PCB. I think that it's connected incorrectly in the bricks we have, and I'm wondering if it's a global problem or some batch\batches. After re-connecting it seems to be charging a lot quicker.
When my Cada brick hangs I simply connect it to some power source and it starts working again.