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VP-X Installation and Operating Manual
Rev. D (August 5, 2020)
The diagram below shows what each item is.
Description of items.
5.5 Master Contactor Wiring
Do not connect the battery until the system is wired and tested.
The master contactor (aka master relay, master solenoid) is controlled
by applying ground to the small post on the contactor. Some contactors
come with two small posts, some come with one. Be sure that you install a
“continuous duty” contactor. The contactor typically draws less than 1 amp
when energized.
• Connect the diode (included with the system) to the battery contactor
as shown below. The diode will extend the life of the contactor, and
may serve to minimize damage to sensitive avionics.
BAT
One Post
Two Post
Note direction of diode
BAT
to master switch
to master switch
• Install a 20 AWG wire from the small post of the battery contactor to
the master switch.
• Connect the other side of the master switch to ground.
BAT
GND
Master
switch
• Connect the main power wire from the battery contactor to the power
lug on the VP-X using a ¼” (0.250”) ring terminal. Cover with a
molded plastic cover. You must use either a 6 or 8 AWG wire for this
cable. Use 6 AWG if the run is over 4 ft or if the max planned load
is >45 amps. Use 8 AWG for all other situations. Torque to 36 in-lb
(3 ft-lbs).
Do not over-torque the nut
– all you need is a snug fit.
The power lug is a soft copper alloy and will break if over-torqued.
Connect the cable to either the battery contactor post or the starter
contactor post – they are electrically identical, but one may be more
convenient than the other depending on your layout.
VP-X
+
Batt
Starter
Contactor
Battery
Contactor
+
Batt
Starter
Contactor
Battery
Contactor
VP-X
5.6
Starter Switch and Contactor Wiring
Function
VP-X Pin
I/O
Starter contactor coil power
J10-1
O
The PPS or a conventional starter contactor is controlled from a switch
which is powered from J10 pin 1. J10-1 is ALWAYS ON (unless the engine is
running) so a switch MUST be installed in between the VP-X and the PPS or
the starter contactor.