Power can be supplied from an external source such as a 5 V or 9 V power bank.
* Available separately
Warning! Charging APS2 / APS3 / internal APS5 batteries at air temperatures below 0° C (32° F) may reduce battery life. When using external power, connect the Power Bank to the device after it has been turned on and working for several minutes.
from Yukon Group 2023