I ran it this morning in the water with out water cooling and the ESC only warmed up a little. One of the 6 cell battery packs heated up very hot while the other only got a little warm, I ran two 6 cell 4200ma packs in series, both were not charged fully when I ran it, and one may have had 0.3 to 0.4 volts more than the other in it and now the hot one does not want to charge all the way.