I agree that Hobbycity has some excellent deals, and I've used their Rhino batteries myself.

In terms of charging a lipo, for longevity you are supposed to charge them at 1C, which basically means that it's going to take about an hour to fully charge. (In case you don't know, 1C means, it is equal to 1 times the number of amp-hours in your battery, e.g. if you have a 2100mah battery (=2.1 amp-hours), you can charge it starting at 2.1 amps. As the battery voltage increases, the current will drop, and your charger will also vary the charge to each cell to keep them balanced. So, assuming that the battery is not completely discharged, it takes a good hour before it's all done.)

Hope this helps, and please excuse me if you already know all this...Chris