How To Check Charger Watts. Voltage x Amperage Wattage. I think it may be faster than the one provided if you use a strong enough power supply my USB C charger is 60W.

Watts represent energy per unit of time. Let me know if you want me to test charging it out tomorrow after I kill my Surface. A Retina iPad mini charger delivers 10 watts 51 volts at 2100 mA.
Wait a few minutes and you will know how fast your battery is charged.
Look at the back side of you laptop there will be label or print saying Input 195V -34 A. So 18W is 36A at 5V and 30W is 6A at 5V. 9V 167A 1503W. If youre not sure which Apple Power Adapter you have check the wattage on the top or bottom of the adapter.

