Cheetah cat doesn?t like water! ZTW seal 200a issue

[Youngbuck]

So I recently purchased a single cheetah with a ZTW 200amp , a nice big high end motor but I?m not sure of the size. It has all OSE 8mm connectors. I finally ordered a few 4s packs 5200 100c . Well I finally did acouple runs on 4s and it went pretty good. Well I finally wanted to do a couple speed passes so I hooked up the two 4s to run in series at 8s and I made two very fast passes and everything went downhill from there. The ESC quit working, I still had power to the servo but the esc will no longer beep or do anything. But the weird part is, it did not smoke or let out any flames or anything!
it still looks and smells brand new but something obviously happened, I was hopping it just had a temperature cut off and would come back on but I haven?t had any luck with that so far!
has anyone had anything like this with the seal ztw?
any suggestions and also is there any companies that work on these in the United States?
thanks

[fweasel]

Jumping from 4S to 8S is quite a leap. While the ESC can handle the voltage, could the motor? What kV is is your motor? A mismatch there could pull crazy amounts of current.

[plinse]

If the boat runs at 4s and you do the step to 8s this step has probably been too big or your way of operation was not SAW-like enough.
The fast setups need a lot of discipline, otherwise you can melt the FETs internally faster as the outside of the ESC can get hot... and you have to know very well what you are doing.

Doing a big step from 4s to 8s does not indicate that you were aware of what you were doing

You have a good chance of an internally burned ESC, as it is sealed you don't smell anything and as it has a high quality metal housing you don't see anything as well.