Be very careful with those packs. They work great, but I got bad batch a couple of weeks ago. I normally would run with the auto lipo cutoff to 3v per cell. Never had a problem with my more expensive brand packs. I did that with the 5s 4000 Zippy-H and 4s 5000 Zippy H and they got waaay out of balance. It took quite a bit of babying to get them back in balance. One of the 5s 4000 packs did randomly die on me though. I changed the LVC to 3.2/cell and they seem to work fine. Good bang of the buck though. I just ordered two more 5s 4000s.