This would probably be better posted over at DRP instead of the Phantom group, but since I am in both I happened to see this. If you do mean the Fatshark goggle battery I would think that 2 of the LED's are the issue, check the voltage with a voltmeter or a simple battery checker on the 2s JST connector. Even though it is not a real 2s connection, it is missing a wire, but most simple checkers will read cell #2 as the full 2s battery voltage.
If on the other hand you mean a Phantom battery, then I think that could be real trouble for that battery.