Battery Interconnect and Harness
HVDC Bus-Bar Network with Robotic-Mate Connectors
High-voltage DC bus bars, cables, and connectors that aggregate rack outputs onto the main DC bus, including robotic-mate connectors at module/rack interfaces that allow L1-MNT to replace units without manual involvement.
Purpose
Carry hundreds of amps at 400 V DC across the battery vault with minimal IR loss, while providing the mechanical interfaces that make the system maintainable by lunar service robots over 100 years.
Context
Physical wiring/bus-bar plant between L3-ESS-LITH-MOD, L3-ESS-LITH-RACK, L3-ESS-LITH-ISOL, and L1-PDM. Mechanically supported by L1-STR vault structure. Mating done by L1-MNT robotic arms for replacements.
Principles
- ▸DC bus-bar sizing: 200 A continuous at 400 V → 80 kW; cross-section ~75 mm² aluminum or 50 mm² copper to keep loss <1%
- ▸Robotic-mate connectors (e.g., Eaton ML series, Stäubli MultiLine) include mechanical guidance, electrical pre-mating, and self-cleaning contacts
- ▸High-voltage cable insulation must withstand vacuum and radiation — Teflon, PEEK, or ETFE preferred over PVC
- ▸Connector pin design: high-current power pins plus low-current sense pins separated for galvanic isolation
- ▸Shielded twisted pairs carry differential signals (CAN bus, BMS sense) — shield grounded one end only to avoid ground loops
- ▸Mechanical strain relief at connector entry minimizes wear during thermal cycling and robotic operation
Typical implementations
- ▸ISS quick-disconnect orbital replacement unit (ORU) electrical interface
- ▸Tesla Megapack DC bus-bar designs (terrestrial heritage)
- ▸Mars 2020 Perseverance HVDC power harness
- ▸ESA Mars Express HVDC interconnect heritage
- ▸Eaton ML series robotic-mate connectors (commercial)
Lunar considerations
- ▸Lunar dust ingress is the dominant failure mode for robotic-mate connectors — labyrinth seals + EDS protection critical
- ▸Thermal cycling (–40 to +80 °C in vault) drives cable insulation fatigue — radiation-cross-linked Teflon preferred
- ▸1/6 g gravity reduces sag but does not eliminate cable management — supports needed for long runs
- ▸Connector polarity keying prevents wrong-direction mating during robotic ops
- ▸Long mission means cables may need replacement via L1-MNT — pre-planned wiring runs and quick-disconnect strategies
Specifications
Functional
| primary function | Carry power and signals between battery modules, racks, and main bus |
| inputs | Power from each L3-ESS-LITH-RACK output, Signal lines from L3-ESS-LITH-BMS |
| outputs | Aggregated DC bus to L1-PDM, Sense/command bus to all rack BMSs |
| main bus voltage v | 400 |
| main bus current continuous a | 400 |
| main bus current peak a | 800 |
| ir loss percent max | 1.0 |
| robotic mate force n max | 50 |
| robotic mate cycles min | 1000 |
| insulation voltage rating v | 1500 |
| data signaling bus | CAN FD over isolated twisted pair |
Physical
| mass kg total | 25 |
| dimensions | Distributed within battery vault |
| materials | Tinned copper bus-bar (50 mm²), ETFE insulation jacket, Eaton ML or custom robotic-mate connectors, Stainless steel cable trays, Polyimide cable ties (vacuum-rated) |
| operating temperature c | -40, 80 |
| vacuum compatibility | True |
| ultimate load g | 6 |
Operational
| power consumption w | 0 |
| thermal range c | -40, 80 |
| lifetime years | 25 |
| mtbf hours | 400000 |
Interfaces
Provides
- Aggregated battery DC bus at 400 V, up to 400 A continuous
- Robotic-mate connector targets for unit replacement
Requires
- Per-rack bus inputs
- Cable tray and conduit mounting
Cite this entry
Lunar Ark Codex. "Battery Interconnect and Harness" (L3-ESS-LITH-CONN). Retrieved 10 September 2026, from https://lunarark.com/entry/L3-ESS-LITH-CONN
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.