[suicideneil]

Charge rate is adjustable upto the maximum power output of the charger- 5amps I believe for your one. If you are trying to charge a 5000mah lipo for example, you wont be able to excede a 1c charge rate regardless as for a 5000mah lipo, 5amps = 1c. The built in powersupply is also a limting factor, as for a 50watt item like yours, that means trying to do a 5amp charge on a 4s lipo will result in the charge rate dropping in order to for it to not excede the maximum power output rating, example:

50watts = 14.8v x 3.7amps, so you only get less than 1c charge rate, regardless of how high you try to set it.

Lipos that can be charged at 2c or 5c need a charger and power supply much much more powerful than what is easily available. For example, to do a 5c charge on a 4s 5000mah lipo:

14.8v x 25amps (5c) = 370 watts + some overhead to allow for losses and 90% efficiency say. Have fun finding a charger and powersupply that can push that kinda power without it costing both your kidneys and your liver....