Section 1: Power Systems¶
System Overview¶
The Jeep LJ uses a dual-battery electrical system with intelligent power distribution and programmable power management.
Power Generation & Storage¶
- START battery: Odyssey PC1500 (850 CCA, 68 Ah) in driver rear wheel well - critical systems only
- AUX battery: Dakota Lithium 135Ah LiFePO4 (108 Ah usable, heated BMS) in passenger rear wheel well - accessories, winch (jump start capable)
- RedArc BCDC Alpha 50: DC-DC charger/isolator - batteries operate independently when isolated
- 270A Alternator: Charges START battery, BCDC charges AUX battery
See Power Generation for complete details on batteries, alternator, BCDC, and solar charging.
Power Distribution¶
Each battery uses a different distribution strategy:
- START battery Distribution: Inline CBs at battery (250A for PMU, 80A for BCDC input) — no local bus, direct stacked terminal lugs
- AUX battery Distribution: Inline CBs at battery (300A master forward feed + 150A SafetyHub local + 100A audio amp local) → Firewall CONSTANT Bus (Blue Sea 2105, 250A) feeds SwitchPros and BODY PDU at the firewall cluster; JL Audio MV800/8i amp fed direct from AUX battery via 100A CB
The system replaces the factory TIPM with modular programmable controllers:
- PMU24: 24-channel programmable power management - engine bay critical circuits
- BODY PDU: Cabin convenience circuits - radio, USB, heated seats, camera
- SafetyHub: High-current safety circuits - ARB compressor, winch contactor
Ground distribution architecture:
- Grounding Architecture: Battery grounds, engine bay ground bus, firewall stud bus, distributed grounding system
Wiring Standards¶
| Standard | Specification | Notes |
|---|---|---|
| Connections | Soldered + marine heat shrink | Waterproof, vibration-resistant |
| Connectors | Deutsch DT series (IP68) | Engine bay and exterior locations |
| Securing | Every 12-18" | High-vibration areas (engine bay, wheel wells, frame rails) |
| Securing | Every 24" | Low-vibration areas (cabin, trunk) |
| Loom | Split loom or braided sleeving | Abrasion protection where routed against metal |
| Grommets | Rubber with sealant | All firewall and body penetrations |
| Temp derating | 60°C for engine bay | Ampacity calculations must use derated values |
| Temp derating | 30°C for cabin/rear wheel well | Standard ampacity values acceptable |
See Wire Distance Reference for routing distances and gauge specifications.
Outstanding TBD Items¶
Auto-derived from this page's section (area/power-systems) — open GitHub issues only.
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