I have both the new and old style of
Spark Batteries. I have never have one come lose or fall off. I have noticed that sometimes you have to be careful and make sure the
battery snaps on fully. I can see how if rushed the
battery may not attach correctly. It's all about taking care and double checking the
battery to see if it's been placed correctly. I always give the
battery a hard tug before launching to make sure it's attached.
One final note, I have sent a few "NEW"
batteries back to the source for not clicking on as firmly as some others that I have received. It seems new or old style
batteries from DJI are not produced with very close tolerances thus
batteries can be better than others with regards to clicking and then staying on the drone.
Regards,
Walt