10-21-2009, 10:51 AM
First of all, make sure of the rate for a given length of charging and use the following rule: Amps = Capacity / Time to Charge. For instance, to charge a 1200mAh battery in 20 minutes requires a current setting of 3.6 amps: amps = 1200mAh / .33 hours = 1.2Ah X 3 hours =3.6 amps. The same rule can also be reworked to determine how long it will take to charge a battery at a given current: Time to Charge = Capacity / Amps. So, the time it takes to charge a 1500mAh battery at 5 amps is 18 minutes: Time to Charge = 1500mAh / 5A = 1.5Ah / 5A = 0.3 hours = 18 minutes. The charging process is not totally efficient; some of the energy is lost as heat, and the charging takes place a little longer than this.