Spektrum SPMAR7100 - Manual (Page 4)

Spektrum AR7100 5 Spektrum AR7100 6
Battery Capacity Recommended Guidelines for Battery Capacity
It is important to select a battery that has more than adequate
capacity to provide the necessary flight time. Our staff has been
recording in-flight data to determine typical current consumption of
aircraft in flight. The following graph illustrates a T-REX Nitro 600
during aggressive 3D flight.
Helicopter -T-REX 600N
Servos - 3-JR8717’s, 1-8900G (rudder), 1-8317 (throttle)
Batteries - 1- 2100mAh 2-cell 7.4-volt LiPo
Engine - YS50
Flight envelope - Aggressive 3D
Average current - 1.15 amps
Peak current - 3.33 amps
Milliamps used per 8 minute flight- 173mAh
In the above example the average current was 1.15 amps, which
calculates to 153mAh per 8 minutes (typical flight length). It’s
recommended that only 60% of the available capacity be used to
ensure plenty of reserve battery capacity. In this example using
2000mAh batteries 2000 x 60% = 1200mAh (available usable
capacity) divided by the capacity used per 8 minute flight, 153mAh
would allow up to 7 flights of 8 minutes each.
For 50-size electric and glow powered helicopters a minimum
capacity of 2000mAh is recommended. For 90-size helicopters a
minimum of 3000mAh is recommended. Our staff uses 2000mAh
LiPos in 50-size helis and 4000mAh LiPos in 90-size machines and
typically flies 4 or 5 flights then recharges.
Following is a picture of a typically recommended installation.