Get the official Raspberry Pi Universal Power Supply (click the green BUY tag at the top of the page).
The more than you ever wanted to know answer:
catalincf wrote: ↑
Sun Jan 13, 2019 1:52 am
Many cable cheap junk dont even have marked any AWG even though are thick as hell. Cutted one Motorola branded thick cable and found out 5 pieces of ''hair'' in the black and red wires (what a cheap joke).
Cables with thin wires are not necessarily cheap junk. The Raspberry Pi uses a USB 2.0 micro USB jack for power, and the USB 2.0 power specification is 5V at up to 500mA (0.5A) of current. Cables don't have to be very thick to transfer 2.5 watts of power. The problem happens when you try to use a standard micro USB cable to power a Pi3 computer that can demand up to 5X that.
When the Pi first came out you could use a phone charger and just about any micro USB cable, and that's still true for the Pi Zero.
However, that is no longer the case with the much more powerful (and power hungry) Pi 3B and 3B+ models, which is why it's recommended to use the official Raspberry Pi Universal Power Supply
. It's not just marketing hype from the Raspberry Pi Foundation. That power supply is a proven performer that works very well, and is usually pretty affordable. It outputs 5.1V at up to 2.5A with good voltage regulation and has a built-in power cable with fat 18 AWG power wires.
Q: Can you use a phone charger?
A: Possibly, but not necessarily...
The problem with phone chargers is twofold.
- Charging phone batteries does not require precise voltage control (most phones only need a little over 4.2V to charge), and because of that, some phone chargers have poor voltage regulation and won't maintain a stable 5V under load. I have a charger rated for 5V & 2.4A which drops well below 5V at only a 1A load. It charges my phone fine, but it's a lousy Pi PSU.
- Phone chargers often use a separate USB cable, and then you run into the problem catalincf found above. Standard micro USB 2.0 cables aren't designed to deliver much more than 500mA without voltage loss. You need a short micro USB cable designed for high current charging (the ones included with smart phones and tablets may work).
So you not only need a phone charger with good voltage regulation, you need a micro USB 2.0 cable designed for high current. Also note that longer cables have more resistance, so you want a micro USB cable with fat power wires that is as short as possible.
This is why phone chargers are not recommended for the Pi 3B(+). You don't really know if it will work unless you can give it a proper load test. It may seem to work fine when you aren't doing anything too heavy, but then you try to play a game or connect a portable hard drive and it crashes, reboots and corrupts your SD card.
Now all that being said, I do have one phone charger that works great, but I did load test it at well over 2A, and I have micro USB cables with fat 21, 20 and even 19 AWG power wires. Unfortunately, that charger has been discontinued.
What about other not-official power supplies advertised for the Raspberry Pi 3B?
They may or may not work. Many so-called power supplies sold for Pi computers are just re-purposed phone chargers.
So yes, powering the much more powerful Raspberry Pi 3B, and especially the even more powerful 3B+ is not as simple as it used to be. But it's hardly a "a never ending story" because there is a proven solution. Click on the green BUY tag at the top of the page, scroll down to the official Raspberry Pi Universal Power Supply and click the BUY NOW button.
My mind is like a browser. 27 tabs are open, 9 aren't responding,
lots of pop-ups...and where is that annoying music coming from?