User manual

57Receiver power supply
Receiver system power supply
NiMH 4-cell battery packs
In compliance with the aforementioned conditions,
your Graupner/SJ HoTT receiver system can be read-
ily operated with traditional 4-cell battery packs as
long as the packs have adequate capacity and volt-
age level.
NiMH 5-cell battery packs
Five-cell battery packs offer a greater voltage toler-
ance than do 4-cell packs.
However, be aware that not every servo available on
the market is able to tolerate the voltage level output
by a 5-cell pack over the long term, this is particularly
true when the battery pack is freshly charged. Some
of these servos react to this with a noticeable “grind-
ing” sound.
Therefore pay attention to the specifications of the
servos you use before making a choice for a 5-cell
battery pack..
LiFe 6.6 V batteries with 2 cells
From a contemporary perspective, these new cells
are the very best choice.
LiFe cells are also available in hard plastic casings
to protect them from mechanical damage. Like LiPo
cells, LiFe cells can be quick charged in suitable
chargers and they are comparatively robust.
This type of secondary cell battery is also rated for
a significantly greater number of charge/discharge
cycles than, for example, LiPo batteries The nominal
6.6 V output of a 2-cell LiFe battery pack does not
present a problem for either Graupner/SJ HoTT re-
ceivers nor for those servos, speed controllers, gyros
and other devices which have been specifically ap-
proved for operation in this – higher – voltage range.
Please note however that practically all servos,
speed controllers, gyros and other devices built
in the past and most such devices currently still
offered on the market have only a permissible
voltage range of 4.8 to 6 V. Use of these batteries
in conjunction with these devices demand use of
a stabilized voltage regulator, e. g. the PRX, Order
No. 4136, see appendix. Otherwise there is danger
that attached devices will incur damage within a short
period of time.
LiPo 2-cell packs
For a given capacity, LiPo batteries are lighter than,
for example, NiMH batteries. LiPo batteries are also
available in hard plastic casings to protect them from
mechanical damage.
The comparatively high nominal voltage, 7.4 V, for
a 2-cell LiPo pack does not present a problem for
either Graupner/SJ HoTT receivers nor for those
servos, speed controllers, gyros and other devices
which have been specifically approved for operation
in this – higher – voltage range. Please note however
that practically all servos, speed controllers, gy-
ros and other devices built in the past and most
such devices currently still offered on the market
have only a permissible voltage range of 4.8 to
6 V. Use of these batteries in conjunction with these
devices demand use of a stabilized voltage regulator,
e. g. the PRX, Order No. 4136, see appendix. Other-
wise there is danger that attached devices will incur
damage within a short period of time.
Charging the receiver battery
Charger cable, order no. 3021, can be plugged di-
rectly onto the receiver’s battery for charging. If the
battery in the model is connected by way of an order
no. 3046, 3934, 3934.1 or 3934.3 power supply cable,
then charging can be accomplished via the charging
jack or special charging connector integrated into the
switch. The switch in the power supply cable must be
in its “OFF” position for charging.
Receiver battery
connection polarity