gtechn wrote: ↑
Mon Jul 01, 2019 5:59 pm
Hello. I know this is a really, really odd question. I have a new official Raspberry Pi power supply coming, and I am wondering what would happen if I wasn't using my Pi and used it to charge a phone (or if someone got it mixed up as a phone charger). Phones charge at about 2.1A, but the charger outputs 3A. Will it step down the voltage to 2.1A or 1A automatically, or will it always output 3A at slight risk of damaging a phone?
Any device will only draw as much current as it--wildly anthropomorphizing here--wants. You could hook up a 100A supply to your phone or a Pi and the phone or Pi would still only draw 2A to 3A. (In practice, don't do this. If there is any sort of electrical fault in the device, it could short the 100A PSU and the results would be...spectacular. And not in a good way.)
Many's the time I've used Pi PSUs to change phones or tablets with no issues at all. Indeed, given the price and quality, I wouldn't be surprised if a great many Pi 3A PSUs aren't bought specifically to be used as chargers.