Is it possible to run Pi Zero from Phone Battery

Question

I would like to create a retro game project and I have to be able to have a portable Pi without being plugged into a electric socket.

I have been looking into my phone battery and saw that it's 4.2v or the other 3.7 volt.

Would it be possible to connect the battery to the Pi Zero and run it like that? The official FAQ says the acceptable range is 4.8 volts.

To my understanding the Pi needs 400mA power to run, however the cap is 5.5 volts, so would it work with lower voltage but with enough power?

What about surge current protection and other electric risks? Does a phone battery have protection built in against that or does it need a custom circuit for it.

If not then please link me to a tutorial that teaches me how to make the Pi Zero run from batter, safely.

Answer 1

Safest and easiest possibility to make your Pi zero portable is to use a USB-powerbank. Any battery with a lower voltage than 4.8v will very likely not work.

Answer 2

While the CPU (but not peripherals) will run on reduced voltage, it is not recommended.

The best solution is to use a UBEC in conjunction with a suitable lithium battery.

DO NOT attempt to use a battery salvaged from a phone. Lithium batteries are hazardous devices, which can cause fire if misused. Use a battery designed for use in a model.

Another option is to use a Powerbank designed for phone charging. These usually supply 5V, although the regulation may not be as good. The other problem with most Powerbanks is that you can either charge OR discharge, but not simultaneously.