Soldering will give you a far better electrical connection than crimping, as it assures that ALL wire strands are attached to the connector.
All Lipos have a minimum charge of 3.0 V per cell, but they usually arrive with 3.7 V per cell. They are not fully charged, but only "surface" charged when shipped.
Wrap the unused wire end until you are ready to solder it, and only deal with one wire lead at a time. Shorting out a Lipo can be quickly disastrous! (<3 seconds!)