Powering the nano via usb port

I have a clone arduino nano and im using it on a project. I dıd some research and i found out several ways to power the board. In the project im using a 12v battery so i didnt want to just connect it via VIN (some people say it might be dangerous). So i bought a 5V regulator to be able to use it without any problems.
And i need some help at this point.

a) Can i just put a usb-b cable at the output of the regulator and connect it to the board via usb port ?

b) Or should i use +5v pin to power the arduino ?

c) Or would it be better to use the regulator at about 7-10 volts and connect it to VIN ?

The output of a 5V regulator connected to the 5V pin is ideal.


A little of that also depends on what you will have connected to the NANO as sensors and such also need power.

That brings into play CURRENT !
Some items need more than others so it would be up to you to work out if what you have is also capable in that regards too !

It is something we see on the forums quite regular, and more so with screens, relays and motors that can draw a little more.
In most of those cases a better power supply or even dual power supplies often fix issues so long as they also have the current to handle the loads. (more is often better)

Bob above is correct - The Nano regulator has to dissipate the heat generated by the current it passes and the voltage drop it creates to give a 5v output for the processor .So if you NANO is powering the odd led , the dissipation ( 12v-5v =7v ; multiply this by the current to give power dissipated ( as heat) is low ; then you can run it from 12v . If you are powering other shields off it , then the extra current at 12v input may overheat the regulator , but say a 9v input might still be ok.
The specifications for the boards are not too helpful here in making this judgement.

You might notice that some clone boards have physically smaller regulators , which makes things worse.