DPSI RV Family Operating Instructions Version 2.0
Page 26 of 48
Battery capacities
Generally, ampacity and capacity of the batteries have to be
considered. Thus, 2 battery packs with 450 mAh are much too small for
e.g. 15 servos of a 3m (10 ft) model. Here, two “2000’s” should be
used, which can be discharged (peak current) with 6C. (C is the
nominal capacity in Ah => a battery of 2.0 Ah can be discharged at 6C
with 6 * 2.0A = 12A). Especially when using digital servos anticipate
higher current consumption.
Our elaborate measurements of a 3m (10 ft) model with 15 digital
servos showed a power consumption of about 0.6 Ah – 0.8 Ah for a 10-
minute flight time. You must therefore proceed very carefully when
calculating for the batteries! Check with the model manufacturer in
case of doubt.
In addition, when selecting the batteries, you should ensure that the
connection cables for the batteries are sufficiently thick. If a battery
with a cable diameter of 0.25mm
2
(AWG 24) is used, the advantage of
the DPSI RV is partially negated, since losses will occur in the thin
cable.
The following calculation applies
:
A highly flexible copper cable with a diameter of 0.25 mm
2
(AWG 24)
and a length of about 25 cm (10 inch) has a resistance (back and forth)
of about 0.05 Ohm. The power handling capacity of this type of cable is
at a maximum of 2.5 A. With a theoretical current of 10 A, the drop in
voltage in this cable is already 0.5 V. Instead of 6.0 V reaching the
DPSI RV, for example, there are now only 5.5 V!
The battery lines for the 3 m (10 inch) models should therefore have a
diameter of 1.0 – 1.5 mm
2
(AWG 16). The battery connection cables
must be soldered to the included Multiplex high-current connectors so
that they are compatible with the DPSI RV. A heat-shrinkable sleeve
for insulating the soldered connections is also included.
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