Personalmente con 7 servi ed una rx spektrum non userei mai una NiMh ma solo Lipo, Life o Eneloop
Non ho la la tua rx cmq il range di voltaggio da manuale risulta essere 3.5V-9.6V quindi la soglia di reset dovrebbe essere l'estremo inferiore del range.
Ad avvalorare quanto appena scritto ti riporto uno stralcio del manuale della tua rx
"Receiver Power System Requirements
Inadequate power systems that are unable to provide the necessary minimum
voltage to the receiver during flight have become the number one cause of in-flight
failures. Some of the power system components that affect the ability to properly
deliver adequate power include:
Receiver battery pack (number of cells, capacity, cell type, state of charge)
The switch harness, battery leads, servo leads, regulators, etc.
The BEC used in the speed controller wont support the current required by the
T
servos.
The AR6255 has a minimum operational voltage of 3.5 volts; it is highly
recommended the power system be tested per the guidelines below.
Recommended Power System Test Guidelines
If a questionable power system is being used (e.g. a small or old battery that may
not support high-current draw, etc.), it is recommended that a voltmeter be used to
perform the following test.
Note: The Spektrum Flight Log (SPM9540) is the perfect tool to monitor voltage
in the test below.
Plug the Flight Log into an open channel port in the receiver and with the system
on, load the control surfaces (apply pressure with your hand) while monitoring the
voltage at the receiver. The voltage should remain above 4.8 volts even when all
servos are heavily loaded.
EN
Note: The latest generations of Nickel-Metal Hydride batteries incorporate a new
chemistry mandated to be more environmentally friendly. These batteries,
when charged with peak detection fast chargers, have tendencies to
false peak (not fully charge) repeatedly. These include all brands of NiMH
batteries. If using NiMH packs, be especially cautious when charging,
making absolutely sure that the battery is fully charged. It is recommended
to use a charger that can display total charge capacity. Note the number
of mAh put into a discharged pack to verify it has been charged to full
capacity.
"
ciao,