Spektrum SPM18000 DX18QQ - Manual (Page 56)

56 SPEKTRUM DX18QQ EN
Recommended Guidelines for Battery Capacity
40–45% Aerobatic aircraft w/ 9–12 high-current servos: 4000–8000mAh
33–35% Aerobatic aircraft w/ 7–10 high-current servos: 3000–6000mAh
25% Quarter Scale Aerobatic aircraft w/ 5–7 high-current servos: 2000–
4000mAh
Jets — BVM Super BANDIT, F86, Euro Sport, etc.: 3000–6000mAh
Giant-Scale Jets — BVM Ultra Bandit:4000–8000mAh
Scale aircraft — The varieties of scale aircraft and the accessories they use vary
tremendously, making it diffi cult to give capacity recommendations for these
types of aircraft. Using the previously mentioned aerobatic guidelines relative
to the size and number of servos used will provide a conservative capacity for
your scale aircraft. As always, check battery charge conditions before each
fl ight.
Battery Voltage
NOTICE: D0 NOT use a 4-cell 4.8-volt battery to power the PowerSafe receiver.
4-cell 4.8-volt batteries do not provide enough voltage headroom (additional mar-
gin needed) necessary to power the system when heavily loaded. Under load, the
system voltage can drop below the voltage system’s minimum operating voltage
threshold (3.5 volts) and cause loss of control.
The PowerSafe receiver is capable of handling voltages from 6.0 to 10.0 volts.
The voltage limitations are generally the servos. Most servos are compatible with
5-cell 6-volt packs. 5-cell 6-volt NiMH packs have become the standard for many
giant-scale applications.
CAUTION: When charging Ni-MH batteries, make sure the battery fully
charges. Ni-MH batteries charged with peak detection fast chargers have
a tendency to false peak (i.e. not fully charge), which could lead to a crash.
Pilots are also using 2-cell LiPo batteries to power their aircraft. LiPo batteries
offer greater capacity for their size and weight, and are easier to manage when
charging. Before using LiPo batteries, please check the voltage specifi cations of
your servos. Use of a voltage regulator, such as the Spektrum VR6007 (SP-
MVR6007), might be necessary.
When a battery is connected to the PowerSafe receiver, a low current drain of
less than 1mA occurs even when the switch is turned off. If the system is going
to be stored for any length of time, it’s important that the battery (or batteries) be
disconnected from the receiver to prevent over discharge.
Installation
The PowerSafe receiver requires a minimum of three remote receivers to operate,
and one receiver must be plugged into the A receiver port. Each receiver functions
independently to offer a more secure RF link in diffi cult environments. The added
security of redundancy should a failure occur will outweigh the slight additional
penalties of cost and weight.
To install the PowerSafe Main Unit:
1. Using foam or thick double-sided foam tape and tie wraps, secure the
main PowerSafe unit in the position where you would normally mount the
receiver.
2. Mount the switch on the side of your aircraft and insert the switch plug in the
port in the main unit marked SWITCH.
The PowerSafe uses a specifi cally designed switch. Conventionally wired switches
are not compatible with the PowerSafe receiver.