SMCs are supposed to be handled a little differently than other lipos - be sure to read and follow the instructions that came with them.

There is another voltage to worry about with lipo - they shouldn't be discharged nbelow about 3v/cell, so a 2S shouldn't be discharged below about 6v. Use a low voltage cutoff - either in the esc if it has one or a separate add on type lvc to protect your lipo.