Do Android phones charge faster when powered off?
yes, android phone charges faster when switched off.
there are also several ways you can improve the charging speed of the mobile phone, like putting your phone on airplane mode or turning on battery saver mode.
while keeping your phone in airplane mode will keep your phone away from radio signals or from getting calls or any notification. but in the background, there will be some activity going on which will take some battery.
when the phone is switched off it is actually not doing anything and does not lose anything.lesser the activity the phone do the faster it will charge.
Try to understand that a bucket never fill up faster when it’s not leaking.