Bedienungsanleitung IFS
Seite 16
capacity pack, but then you have to ask yourself “what is my model worth to me, and am I willing
to take a chance with an improper power setup?”
5 cell packs:
5 cell packs offer additional voltage headroom. These are a better choice than a 4 cell pack.
Note that some servos will not handle the voltage of a 5 cell pack. Please consult the
specifications of your servos before using a 5 cell pack.
A123 flight packs:
These are the best choice. They provide a voltage higher than a 4 cell pack, but less than a 5
cell pack. The current capabilities of these batteries exceed what any 4 or 5 cell NiMh or NiCd
pack can provide.
2 cell Lipo packs:
Newer high voltage servos can use a 2 cell Lipo pack. This works fine as the Graupner|iFS-
receivers can handle voltage up to 10 volts.
Just please note that the input voltage to the Graupner|iFS-receiver is not regulated, so the full
input voltage is passed to the servos.
Please remember that wall chargers included with most radio systems are designed only for 4
cell packs. These chargers are typically 50mA, meaning that 50mAh of current sput back into
the pack every hour. A 2000mAh pack would require 40 hours to charge from a completely
drained state and 20 hours if the pack was half way discharged. An overnight charge would not
work in either of these cases!
5.2 Load Testing, BECs, and Switches
We recommend that you always load test your power system using at least a 1.5A load before
every flight. Several companies make inexpensive load and voltage testing devices. These will
determine if your battery pack has the capacity required to fly your setup. Otherwise, move all
stick fast at the same time to simulate a realistic load
Battery Eliminator Circuits (BECs) are great for small aircraft where loads are very light.
However, beware of ANY “linear” regulators, even the so called “high current” versions.
“Switching” regulators are far more reliable and generally do not get hot or change output
voltages with heat or load.
BECs built into Electronic Speed Controllers (ESCs) must have enough current capacity to
properly power the Graupner|iFS-receiver. We have seen many controllers that will not work.
Although switches make it convenient to turn our R/C systems on and off, they can be the cause
of system failures. Even heavy duty switches typically have a 0.2 Volt drop across them when
brand new. As switches age they oxidize, and constant vibration wears the metal contact plates.
We have seen 0.7 volt drop with a heavy duty switch after one season of flying.
5.3 Charge, Charge, Charge!
You can never have a flight pack that is too full. We recommend “topping off” your flight packs
between flights. Often times you don’t fly back to back flights and there is ample time to do this,
especially when using LiFe-flight packs where a “top off” could literally be just a few minutes.
