Each Lithium Polymer battery pack has a different maximum charge rate. It is very important to never ever charge at a rating above the specified rate!
Most batteries have a label that specifies this vital information. However, if the maximum charge rate is not specified, keep in mind that most Lipos are made to be charged at a rate of 1C. Which means a 1000 mAh pack can be charged at 1A and a 500mAh pack can be charged at 0.5A. Once again, never ever exceed the maximum charge rate lest the battery explodes!