Take the mobile phone charger as an example, 2.4a is equal to 12w. According to physical knowledge: because power P= voltage U* current I, the rated voltage usually used by the 2.4a charger is five volts, so the power of the 2.4a*5v charger is 12w.
The specification used by the ordinary charger is five volt 1a, its charging power is only about 5W, and the charging power of the 2.4a charger can reach 12w, which is much more efficient than the general charger
So the 2.4a charger is 12 watts
6.6v2.4A is an 18 fast charger, 18v type, charging as long as one hour full, this charger is also expensive, twice as expensive as 9V.