Battery capacity – Spektrum SPMAR9110 User Manual
Page 9
EN
9
Battery Capacity
It’s important to select a battery(s) 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. Following are
two graphs that illustrate the in-flight current draw of the radio system.
Note: Current draws may vary depending on your servos, installation
and flying style.
The following setup is shown as a worst-case scenario indicative of some
aerobatic pilots’ setups. It is not recommended to use this setup without
proper voltage regulation for your servos.
Airplane: 40% YAK
Servos: 9-JR8711’s 1-8317 (throttle)
Batteries: Two 4000mAh 2-cell 7.4-volt LiPos
Regulator: None
Note: JR8711’s and 8317’s are rated at a maximum of 6-volt 5-cell use.
Using higher voltages will void the warranty.
Engine: DA150
Weight: 40 lb
Flight envelope: Hard 3D
Average current: 2.62 amps
Peak current: 17.8 amps
Milliamps used per 10-minute flight: 435mAh
File: JasonNoll.FDR Session:All Sessions
Seconds
350
300
250
200
150
100
50
Pa
ck
Am
ps
_A
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
PackAmps_A: Min 0.00 Max 17.80 Avg 2.62
450
400
0
In the example above, the average current was 2.62 amps, which calculates to
435mAh per 10 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 two 4000mAh batteries (8000mAh total capacity) x
60% = 4800mAh (available usable capacity) divided by the capacity used per
10-minute flight, 435mAh would allow up to 11 flights, of 10 minutes each.