Switching between charging vs no-charging when connected to external power source?

[Seswu]

Hello;

Generally laptops and mobiles will charge themselves whenever they are plugged in to an external power source.

However, I'd like to use a Cutiepi during travel, and well beyond the 5 hour window.
I figure I can use power banks for this, -if- there is a mode available in which the device will not auto-charge.
Continually charging one battery from other batteries would be a waste of energy and available work time.

Is there a physical switch between auto-charging and no-charging, ie merely powering the Cutiepi from the external power source?
Or can it be done through software?

[sp00ck]

and switch for turn on/off :
wifi
BT
usb
reduction memory rate/speed
cpu decrease speed
and ofcourse screen ;)