I work with two way radio's all the time, and with new Li-ion batteries I have run into this problem quite a bit. What I believe is happening is that when you discharge "too low" that the charger is seeing the battery as "BAD".

With a variable voltage power supply on my bench, I have been able to jump start the battery to get its voltage level up just enough that the charger then see's the battery as good and begins to charge again.

For example, a typical radio battery runs at 7.2 volts, but after being discharged too low may be at 5.5 volts. I put my power leads on the corresponding + or - leads, with my voltage set for 7.2 volts. This will equalize the low battery bringing it up to say, 6.5 volts, depending on length of time you charge it.

This should bring it up to the level the charger needs to see for it to work. The same thing could be done with a Lithium AA, you could jump start it with an alkaline AA, just be careful not to over do it. A quick 20 second charge is usually all that is needed.

Edited by Vance (01/12/21 04:48 PM)