How Many Babies Can A Bat Have At Once?

Usually only one a year.  The baby isn't left somewhere
while the mother hunts until it older.  Until then it clings to
Mother's belly even in flight.  More than one would either
be too heavy or the jostling could cause one or both of the
babies to loose it's grip and fall.  In the caves where bats
have roosted for any length of time have floors feet-deep
in guano (bat poop).  Crabs, cock roaches and other hungry
things live on and even in that covering.  Any bat that falls,
no matter the age, is doomed.   It will be eaten by what
lives below.