Its hard to beat a LiPo power for portable field operation. This is a kit with 3 cells from Nitecore, 3 "dummy" cells to pass power and a 3x1 USB-C charging cable. Each cell has its own integrated overcurrent, overcharge and over discharge protection. As each cells is individually protected, and of the same age, cycle count, and of course chemistry, a uniform discharge is expected and therefore no BMS is included. Enjoy 1Ah of 9-12.6v power for the KX1.
No need to solder or remove the battery holders. Simply install the three Nitecore cells and the three dummy cells, charge and go play radio!
Charge all three cells together until full by plugging in the included charging cable to each cell with no need to remove from the radio, simply open the back cover. Each cell has a redlight to indicate charging and a green light to indicate complete charge.
Do not add other cells or mix other batteries with this kit. You should never use more than 3 LiPo cells in series to power a stock KX1 radio.