Spektrum SPMAR12120 - Manual (Page 5)

EN
5
It’s normal for one battery to discharge slightly more than the other. This is the
nature of a truly redundant isolated battery system. The battery that has the higher
voltage or lower internal resistance will discharge at a faster rate. Generally the
difference is negligible (less than 10%). Because of this it’s normal for only one
blue LED (Batt 1 or Batt 2) to be on when the system is not under a heavy current
load depending on which pack is providing more power.
When using two batteries, the total available capacity equals the sum total of
both batteries e.g., BATT1—2000mAh + BATT2- 2000mAh = a total capacity of
4000mAh. 12- and 24-inch EC3 battery extensions are available for installations
where the battery is located a distance from the main PowerSafe unit.
Using Dual Voltage Regulators
Spektrum offers a 7.5 amp (11-amp peak) 6.0 volt regulator (SPMVR6007) specifi-
cally designed for use with the AR12120 PowerSafe.
IMPORTANT: When using two batteries powered through two regulators, each
regulator operates independently and it’s common for one battery to be dischar-
ged at a slightly higher rate depending on the condition of the battery (internal
resistance, voltage, etc.) and the tolerance of the regulators. This causes one
battery to discharge before the other and it’s important to check each battery
using a loaded battery tester (HAN171) at a recommended 1-amp load before
each flight monitoring the voltage of each pack and recharging when the
weakest pack reaches 40% capacity. (See Battery Capacity pg. 5)
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. Current draws may vary
depending on your servos, installation and flying style.