Posted to FB Arduino group Sep 23
Mbihi Oliver
Four hours is twice as long as 2 hours with the correct charger. Here is a secret many don’t know: Smartphones don’t necessarily charge at maximum, especially if they’re charged by a charger not made for their phone.
Smartphones often have a sensing circuit that checks to see if the plug’s two data pins are connected a certain way, such as two resistors to + and -. If so it tells the phone that it’s the correct charger and it will accept full current, 1.5 amps or more.
But if these pins are open or the wrong resistance, then it charges at a half amp, because the original USB port is only specified for 0.5 amp. So it won’t blow out the USB port on your MoBo.
Does your homemade charger have this?? 😱 😈