In reply to G4OWG:
Battery only giving 2V.
2V for a 2 cell Lion pack means totally dead. It won’t recover. It is correct not to attempt to charge it. What you don’t know is whether a fault in the radio killed it, or whether it died of old age.
How many connections does the pack have? 2 or 3? If 3, then they are probably connected to the raw cells and the protection circuitry will be in the radio. If 2, then there should be a circuit in the battery pack - but there may not be, and that may account for premature failure if the cells became unbalanced.
(Essentially there’s no way to handle a series connected lithium pack properly without being able to monitor individual cells).
If the pack is more than a couple of years old or has had more than a couple of hundred cycles then I’d be inclined to risk getting a new one. If it is relatively new then I’d be a bit suspicious of the radio, but it would doubtless cost you a fair bit just to get it checked out. That would be annoying if nothing was wrong - and you still need a new battery anyway.