Connectors are an important element in any electric
power system, and you’ll find them in between motors
and ESCs and between the ESC and the battery pack. The
most important thing to remember is to use a proper size
connector for the battery and power system being used.
Most of the battery manufacturers today include connectors already attached to the power leads or at least
include them in an accessory bag. Using a low-quality
connector or one that’s too small increases resistance in
the wiring and this translates to heat and loss of power.
As a rule, you should use as few connectors as you can
to maximize efficiency. Many experienced modelers will
eliminate the connectors between the motor and ESC by
soldering the power leads directly together.
Most brand name electric equipment has its own brand
and type of connector, and you need to use the matching type to charge your battery packs. You can, however,
simplify your life by switching all of your battery and ESC
connectors to a generic one. This will then allow you to
mix and match battery packs between airplanes and you
can use the same charger to service your battery packs
... if, the charger has the proper settings to match your
packs. The most common are Deans’ Ultra T-configured
connectors and Anderson Powerpole (APP), also referred
to as Sermos connectors. The Deans require soldering and
some heat shrink tubing, while the APP connectors can be
soldered or crimped onto the power leads with a special
5Connectors come in all shapes and sizes. Never use a connector or charging lead that’s
damaged. It could cause a
short and can damage your
charger or ESC.
Having a good time while flying is the ultimate goal. When
you learn the basics, electric power is a very safe and
efficient way to commit aviation.
Ampere (amp): The standard unit of electric current. The
current produced by a pressure of one volt in a circuit
having a resistance of one ohm.
Battery eliminator circuit (BEC): A circuitry that allows the
battery that runs the motor to also power the receiver and
the servos. This is often built into the ESC.
Brushed motor: The traditional type of electric motor
where brushes make contact between the rotor and the
stator. The touching of the brushes essentially creates the
timing and current to make the motor spin correctly.
Brushless motor: This is a type of electric motor used in RC
electric aircraft. Brushless motors are much more powerful than traditional brushed motors and are commonly
used in electric aerobatic aircraft. They can be inrunner or
Current: The flow rate of electrical energy. Measured in
Capacity: A measure of how long you can draw a specified
current from a battery. It is measured in amp hours (Ah), or
more commonly for the scale of equipment used for electric flight, milliamp hours (mAh).
Electronic speed controller (ESC): The thing that controls
how much current is given to the motor and hence how
fast the motor runs. Often they have a BEC (see above)
built in. There are two main types: brushless and brushed.
Horsepower (HP): A measure of the rate of work. 33,000
pounds lifted one foot in one minute or 550 pounds lifted
one foot in one second. Exactly 746 watts of electrical
power equals one horsepower.
Inrunners: These get their name from the fact that their
rotational core is contained within the motor’s can, much
like a standard ferrite motor. They run inside the can.
Kv: A rating for a brushless motor that equals 1,000rpm
per volt. So a 5Kv motor would spin at 55,500rpm approximately if you applied 11.1 volts (3S).
LiPo: Stands for lithium-ion polymer battery. These are
the most modern kind of battery pack being used in electric aircraft. They provide enormous amounts of power
for their size, especially when used in conjunction with a
mAh (milliamp hour): A measure of a battery’s total
capacity. The higher the number, the more charge a battery can hold and, usually, the longer a battery will last
under a certain load.
Ni-Cd: Abbreviation for nickel cadmium. They are a form
of rechargeable battery cells used in radio control gear as
well as motor battery packs. Ni-Cds are being used less
and less these days, as NiMH and LiPo batteries take over.
Ni MH: Abbreviation for nickel metal hydride batteries, they
are the successors to Ni-Cds with much better performance and up to three times the capacity for an equally
sized battery. Only LiPos top NiMHs.
Outrunner: The other type of brushless motor, where the
outer shell, or “can,” of the motor rotates with the shaft.
The extra inertia produces more torque, so outrunners are
more powerful than inrunners and rarely are geared.
Power: For electric models, this is a product of voltage and
amps and is measured in watts.
RPM (revolutions per minute): The number of times an
object completely rotates (360 degrees) in one minute.
Voltage: A unit of electromotive force that, when applied
to conductors, will produce current in the conductors. Voltage is also referred to as electrical pressure.
Watt: The amount of power required to maintain a current
of one ampere at a pressure of one volt when the two are
in phase with each other. One horsepower is equal to 746
watts. Watts are the product of volts and amps.