Thanks for the reply Dave but it’s Kaleb - @Huesoro who has the drone problem 
It’s a little mobula 7o4. So trying to revive a dead batterie might be too much. I already cleaned the drone and checked that the o4 works.
The batteries are easily replaced. And inexpensive.
Either of the first two on this page will fit:
But it may be worthwhile investigating further - this review recommends higher capacity, heavier batteries to improve stability: