Connected E3 not charging after 6 months in drawer

Hello

My friend is selling his Connected E3 and has given it to me to try out. It has been in a drawer for 6 months and when I came to charge it, apart from the TAG logo appearing on the screen and then disappearing, nothing is happening. I saw the battery was at 0% when I did first start it

Is there a factory rest /firmware update or is it 'duff'

Its been in charge for 3 hrs and nothing !

Help!

If the battery had very little charge in it before it was put away then there is a good change the battery is screwed. The watch should be able to last 6 months in the off position but with maybe 70 % charge at the start. I have stored the second gen watches for six months previously on a full charge and when I got back to it , it needed a good charge as it was almost empty but worked fine.