After my Fatshark goggle battery was broken, I got a new LiPo battery.
But the new one has no battery indicator. So I made a holder for the LiPo Buzzer, which you can get on e-bay for round about 1 Euro.
I taped the buzzer because it's to loud near ears, when alarm was triggered.
By the way, you can also use to carry this little measurement device in other RC-hobbiest-situations, in which no goggles are necessary.