Yes ,indeed a 5V USB powerpack ,readily available ,even from supermarkets , will do fine.
For those needing a Li-Ion cell (nominally 3.7V) , I get these from discarded Laptop battery packs . These packs are discarded because usually only 1 of the 6 cells is no longer OK.
I take these packs to bits and charge each cell individually with an appropriate charger (usually good for charging 4 cells at the time) I then fit cells in 18650 cell holders available from Banggood and other on-line retailers.
There are 2 types of cell holders , for 1 cell and 4 cells.
WIth the cell holders I make multiple cell battery packs to feed my Yaesu FT-817 , QRP transceiver
For this transceiver I use 4 multiple cell units in series ,ensuring that the cells will be re-charged when the radio input voltage has dropped to 4*2.8V=11.2V To ensure a long life a Li-Ion cell should not be discharged below 2.8 V
The above just for info.
After all I am just a radio AMATEUR.
Frank , EI7KS
