This is the only solution I have found at the moment until the plugin author comes up with a better solution. You have to create your key with Google APIs. You will then need to add the key to:
advanced-custom-fields/js/input.js
advanced-custom-fields/js/input.min.js
input.js is a bit easier to find. On line 2282 you will see:
if( typeof google === 'undefined' )
{
$.getScript('https://www.google.com/jsapi', function(){
google.load('maps', '3', { other_params: 'sensor=false&libraries=places', callback: function(){
$fields.each(function(){
acf.fields.google_map.set({ $el : $(this) }).init();
});
}});
});
}
else
{
google.load('maps', '3', { other_params: 'sensor=false&libraries=places', callback: function(){
$fields.each(function(){
acf.fields.google_map.set({ $el : $(this) }).init();
});
}});
}
At the end of places (inside the ‘), you need to add:
&key=*YOUR_API_KEY*
So it will look like:
google.load('maps', '3', { other_params: 'sensor=false&libraries=places&key=*YOUR_API_KEY*', callback: function(){
It is harder to find in the min file for obvious reasons, so well tailored Find/Replace will work here.
I will say that the min file is what is read from the back end, so it is the file you have to make this edit to.
Hope that helps.