My son is building an EDF. He has the Castle Creation Pheonix 60 amp ESC. He is set up for both 4s2p and 5s2p depending on which packs he uses. Tonight he cooked his second expensive receiver trying to test run the setup. The instructions say the unit has a bec that can handle up to 12 cells. What is the deal with lipos and these speed controllers. This is getting expensive quickly. Can someone explain please? Thanks Doug