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1.1.5 Wire Distance Reference

Measured wire routing distances between major electrical components for voltage drop calculations and wire sizing.

Measurement Method

These distances represent actual measured cable routing paths (not straight-line distances) following frame rails, firewall passages, and avoiding obstacles. All measurements are one-way cable length.

Dual Rear Wheel Well Battery Configuration

Both batteries located in rear wheel wells for optimal wire routing:

- **Driver Rear Wheel Well** = START battery (critical systems)
- **Passenger Rear Wheel Well** = AUX battery (accessories)

Component Distance Matrix

From To Distance Notes
Alternator START battery (driver rear wheel well) 8 ft Primary charging path
Starter START battery (driver rear wheel well) 6 ft Cranking power
PMU24 START battery (driver rear wheel well) 7 ft Critical systems power
BCDC Alpha 50 START battery → AUX battery 5-6 ft Inter-battery charging (BCDC in passenger rear wheel well)
Winch (front bumper) AUX battery (passenger rear wheel well) 13 ft Recovery system power
OEM Battery (engine bay) Starter 4 ft Reference: original configuration
OEM Battery (engine bay) Winch (front bumper) 5 ft Reference: original configuration
OEM Battery (engine bay) Alternator 4 ft Reference: original configuration
Firewall (driver side) Tail lights 13 ft Rear wiring runs
Steering column Driver headlight 6 ft CT4 lighting control
Steering column Passenger headlight 9 ft CT4 lighting control
Steering column Driver tail light 11 ft CT4 lighting control
Steering column Passenger tail light 16 ft CT4 lighting control
PMU (engine bay) Steering column 3 ft PMU to CT4/controls
Passenger rear wheel well A-pillar 7 ft AUX battery to front accessories
Passenger rear wheel well Roof 6 ft AUX battery to roof-mounted equipment

Optimized Wire Gauge Specifications

Wire gauges optimized for performance at measured routing distances:

Circuit Distance Wire Gauge Max Current Voltage Drop @ Temp Notes
Alternator → START battery 8 ft 2/0 AWG 270A 2.81% @ 60°C Charging system - temp derating applied
PMU24 Power Feed 7 ft 2/0 AWG 220A 2.40% @ 60°C Direct connection via 250A CB - upgraded from 1/0 AWG
Starter Motor 6 ft 2/0 AWG 400-600A <3% @ 20°C Brief cranking load - minimal temp effect
BCDC Inter-Battery 5-6 ft 4 AWG 50A 0.94% @ 20°C Rear wheel well to rear wheel well (cross-cab routing TBD - see Wire Routing)
Winch → AUX battery 13 ft one-way (26 ft circuit) 1/0 AWG 250A typical, 400A peak 6.3% @ 250A, 10.1% @ 400A @ 20°C Passenger rear wheel well to front bumper routing (path TBD - see Wire Routing)

Temperature Derating Notes:

  • Engine bay circuits (alternator, PMU) calculated @ 60°C ambient
  • Wheel well circuits (starter, winch) calculated @ 20°C ambient
  • Voltage drop percentages shown at maximum rated current

Measurements Needed

Distances required for voltage drop calculations and wire purchases. Measure actual routing paths, not straight-line.

Lighting Circuits (Priority: High)

From To Wire Distance Purpose
CT4 (steering column) Driver headlight 14 AWG 6 ft ✓ Low/high beam voltage drop
CT4 (steering column) Passenger headlight 14 AWG 9 ft ✓ Low/high beam voltage drop
CT4 (steering column) Left fender turn signal 14 AWG 6 ft ✓ Same as driver headlight
CT4 (steering column) Right fender turn signal 14 AWG 9 ft ✓ Same as passenger headlight
CT4 (steering column) Driver tail light 14 AWG 11 ft ✓ Turn signal rear
CT4 (steering column) Passenger tail light 14 AWG 16 ft ✓ Turn signal rear
PMU (engine bay) Rear tail lights 16 AWG 13 ft ✓ Brake/reverse/marker (Out 21/22/23)
SwitchPros (firewall) Roll bar dome lights 16 AWG ~8 ft Low current, estimated
PBS-I PURPLE START Cole Hersee 24213 coil 16 AWG ~10 ft ✓ Via WAIT-gate relay + firewall Pin 15
CT4 SW3 output PMU In 7 18 AWG 3 ft ✓ Same as steering column → PMU

Offroad Lighting (Priority: Medium)

From To Distance Notes
SwitchPros (firewall) A-pillar ditch lights 7 ft ✓ Via Baja harness
SwitchPros (firewall) Roof 6 ft ✓ Roof-mounted lights
SwitchPros (firewall) Rear rock lights (2) 2-3 ft Low current, voltage drop negligible
SwitchPros (firewall) Front rock lights (4) ~10 ft Estimated via frame rail

Air System (Priority: High)

From To Wire Distance Purpose
SafetyHub (engine bay) ARB compressor (under seat) 6 AWG × 2 ~8 ft Compressor power (through firewall)
ARB compressor Chassis ground 6 AWG ~2 ft Local ground
SwitchPros (firewall) Compressor control terminal 14 AWG ~6 ft Control signal
Air manifold (under seat) Front axle locker Air line ~6 ft Custom air line
Air manifold (under seat) Rear axle locker Air line ~6 ft Custom air line

Communication (Priority: Low)

Location/Route Purpose
STX intercom mounting ✓ Dash/behind dash
GMRS radio mounting ✓ Dash (~6 ft to A-pillar antenna)
Ham antenna position ✓ Passenger A-pillar (~4 ft to dash)
Rear camera cable path ~11 ft (windshield → A-pillar → rear center)

Mounting Locations (Priority: Medium)

Component Status
SwitchPros power module ✓ Firewall (cabin side, passenger area, with BODY PDU + Firewall CONSTANT Bus)
SwitchPros control panel ✓ Dash mounted
SwitchPros control cable length 5 ft (firewall to dash, short run)
Firewall CONSTANT Bus ✓ Firewall (cabin side, passenger area)
Firewall CONSTANT Bus feed 2/0 AWG, ~13 ft from AUX battery+, 300A CB at battery
CT4 GPS antenna ✓ Integrated in CT4 unit
Rear cargo rocker switch ✓ Blue Sea 4160 on rear wheel well top
Rear seat dome override switch ✓ Blue Sea 4160, rear passenger accessible