“What brand is it and how old is it”
That’s what i want to know too.
It’s kind of normal that the voltage drops after throtteling up.
Take a look at my example of my hexacopter, running on a 4S Multistar 6600mAh (10C)
These batteries cannot hold power that good i.m.h.o.
You can see the voltage dropping fast, but during flight it’s rather stable.
