14.4V very strange voltage.
Usual Li-Ion cell has nominal voltage 3.7 V. It should be charged max to 4.2 ± 0.05 V. Military grade should use max 3.92 V instead of 4.2 V. So, your charger should stop charge when voltage on one cell of Li-Ion accumulator is close to 4.2 V but should not exceed this voltage even for 0.05 V!
Since you have battery pack, it looks like your battery has 4 cells. So, the charger should use 4.2 * 4 = 16.8 V limit.
So, just connect the battery and make sure that your charger apply charging voltage to the battery and stops to charge it below 16.8 V.