Assuming you use a MBP on a MBA charger, then light use will likely never draw enough power to max out the charger. The same rules apply, it will draw the power that it needs, and no more. If you use a MacBook air that is supplied with a 45 W adapter with an 85 W adapter instead, it will still only draw what it needs, which is likely a whole lot less than the rated capacity of the charger anyway, which is rated to be able to not only keep the computer going at full bore if required, and also charge the battery at the same time.Ģ) Using a lower rated power supply than the original unit.Ĭhances are this is fine most of the time but there are more risks.
The power supply will never just automatically run at 100 % of it's capability, it will only supply what is requested. 1) Using a higher rated power supply than the original unit.
