Page 7
Pro-120 controller instructions
at the controller to fall so low that the controller
detects a fault condition and the relay will switch off.
On the 24v versions, use of wire that is too long
(and/or too thin) will cause loss of power but will not
harm the controller although the decoupling
capacitor (see ‘features’ diagram above) may heat
up. Heat will shorten the operating life of capacitors.
Crimp Contacts
You must use fully insulated crimps: the power
connections are close to each other and uninsulated
crimps may short out and cause damage. Best of all
use ‘F type’ crimps with vinyl covers. 4QD can
supply these pre-crimped only as they require a
special crimp tool.
8.02
Motor wiring
This is not quite so critical as battery wiring: too
long and/or too thin wire will cause a loss of
performance, it will get and will waste battery power
but will not damage the controller. However, wire
which is too thick will do no harm either so we
recommend the same wire for the motor as for the
battery.
8.03
Circuit breaker
A fuse or circuit breaker may be fitted if required.
The main advantage is that it will enable the battery
or motor to be disconnected in the event of an
emergency or for security. A circuit breaker will not
protect the drive in the event of a fault: MOSFETs
fail far faster than a circuit breaker can operate.
This may be fitted in the battery lead as shown: take
care not to increase the wiring length too much.
Also, certain types of breaker can have the same
effect as increased battery lead length. A breaker in
the motor may therefore be best: it will enable you to
quickly disconnect the motor in an emergency. Also
with the motor disconnected, freewheeling becomes
possible. It is also possible to get a battery isolator
switch - these are normally fitted to lorries, buses
and boats to isolate the battery in an emergency - but
this is not required as the Pro-120 has a power relay
which effectively disconnects the battery (except for
a small bleed resistor).
8.04
Battery condition meter.
This should connect between Pins B and F (white
and green on the diagram). White is connected via
the ignition switch to battery positive and green is
always connected via the wiring to the battery
negative.
9 Controls
The mating connector supplied is
suitable only for the correct size of wire.
Acceptable wire sizes are:
7 stranded 0.22-0.25mm²
24 AWG (7/32 AWG)
It is an Insulation Displacement
Connector (IDC):
Do not strip the insulation from the
wires, simply push them into the top part
of the open connector, from the front
(visible in the diagram) and squeeze it
closed in a vice or with suitable parallel
action pliers. As you do so, the tines of the contacts
bite through the insulation to make contact with the
conductors.
You can re-open a closed connector by gently
moving the tabs at the sides of the top cover outward
to disengage the latches while lifting the cover
slightly, one side at a time.
Wire which is too thin will not make good contact.
Wire which is too thick will damage the tines which
may short to each other
Solid wire will quickly break with use.
Under no circumstances should you solder to the
connector or the circuit board.
A
B
C
D
E
F
Closed
Open
D red: Max speed (about 7v when ign on)
E blue: Wiper (0 to Max Speed, as pot is varied)
F green: 0v (Min speed)
C black: Reverse (0v = forward, >5v = reverse)
A yellow: +24v (V Batt) to Ignition
B white: Ignition
A B C D E F
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