You have done something wrong there, because LiPo batteries have a huge current capacity.
Or might be a bad battery / bad battery protection circuit.
RC LiPo batteries typically do not have any protection circuits.
If the user has drained the battery too low, it will have lower current capacity, and also added instability.
I would recommend to the original poster, that he also order one of those rc low voltage alarms, so he doesn't accidentally overdischarge.
As for voltages, a 7.2V RC Li-Po should come off the charger at slightly less than 8.4Volts. and can be considered empty when the voltage starts going below 7V..