[jhautz]

Lipo chargers dont use the peak meathod for charging. They use a Constant Current / Constant Voltage method.

They basically put out the current that you set based on 1C of the mah of the pack and when the correct votage is reached (16.8v in this case) they switch to a constant voltage output. Where the current is lowered slowly to keep the cell at the 16.8v untill it wont take any more charge.

If yours shut down early there may be some sort of safety set on the charger that limits the mah that it will put into a pack or will only charge for a certain amount of time as a safety.

WHat charger are you using?