Power Management

Solar panel output varies by panel orientation, sun angle, seasonal position, and atmospheric conditions. Measured values represent direct measurement under specified conditions.

Optimal tilt angle by corridor: Northern corridor platforms achieve maximum collection at 45–50° tilt angle during mid-season traverse, with seasonal adjustment of ±15° providing 5–8% efficiency gain in spring and fall months. Central corridor operations use 30–35° baseline tilt year-round, with minimal seasonal adjustment required. Southern corridor platforms maintain 25–30° tilt for maximum collection across all seasons. Single-axis tracking (automated adjustment along primary axis) increases collection by 15–25% relative to fixed-angle mounting; dual-axis tracking increases collection by 25–40% but requires mechanical power input and increases system complexity.

Collection efficiency under non-ideal conditions: Overcast sky conditions reduce measured output to 40–60% of rated clear-sky output, depending on cloud density and distribution. Dust accumulation on panel surfaces reduces output by approximately 2–5% per day without cleaning, scaling with local atmospheric dust concentration and particle size. Fine dust (1–10 micron) accumulates more rapidly and reduces efficiency more severely than coarse dust. Canopy cover (forest, dense brush) reduces output by 10–30% depending on canopy density, leaf area, and sun angle relative to canopy gaps. Partial canopy cover (40–60% of panel area shaded by foliage) typically reduces output to 50–70% of open-sky rating. Dense canopy (80%+ shaded area) reduces output to 10–30% of rated output.

Battery storage capacity is measured in watt-hours (Wh), representing total electrical energy stored. Discharge characteristics depend on load level, temperature, and cycle count.

Temperature effects on capacity: Battery performance degrades predictably with temperature reduction. Each degree Celsius below 0°C reduces effective discharge capacity by 1–2% depending on battery chemistry. At −10°C, effective capacity is reduced to 80–90% of nominal. At −20°C, effective capacity is reduced to 60–75% of nominal. These capacity reductions are temporary; capacity recovers as temperature returns to nominal range. Cold-weather operation requires reducing load levels proportionally or accepting shorter operational periods between charging cycles. Preheating battery systems to 15–20°C before high-load operation restores capacity within 1–2 hours.

Cycle count and degradation: Lithium-based batteries degrade approximately 0.1% per complete charge-discharge cycle (cycle counted as one full 0% to 100% charge event). After 1,000 cycles, nominal capacity is reduced to approximately 90% of original capacity. After 3,000 cycles, nominal capacity is reduced to approximately 70% of original capacity. Degradation rate increases nonlinearly after 3,000 cycles. Partial-cycle charging (charging from 20% to 80% rather than 0% to 100%) extends cycle life by approximately 50% by reducing stress on battery terminals and chemical layers.

Minimum operational reserve: Safe continuous operation requires maintaining minimum 20% battery charge. At 20% capacity (4,000 Wh on a 20,000 Wh battery), system power output is reduced to 50% of standard performance to maintain battery health and avoid deep-discharge damage. At 10% capacity, only critical systems (navigation, essential sensor input, communication beacon) operate. Below 10% capacity, the system enters survival mode with all non-critical systems powered down. Complete discharge (0% remaining charge) causes battery damage and may result in inability to recharge without external power source.

Power consumption varies by traverse speed, terrain class, and sensor configuration. Daily power budget must account for all concurrent loads and establish sustainable consumption within available collection capacity.

Flat grassland terrain (low-friction surfaces, minimal gradient, clear solar exposure) requires approximately 1,350 Wh per kilometer of travel at 6 km/h average speed, including continuous sensor operation and basic lighting when conditions warrant. Net power generation exceeds consumption by significant margin, allowing battery charging even during active traverse.

Rolling terrain (intermittent gradient, mixed surface conditions, variable canopy) requires approximately 2,875 Wh per kilometer of travel at 4 km/h average speed. Daily budget is marginal; battery charge remains stable with moderate solar input but requires stationary charging period to recover reserve capacity.

Mixed forest traverse (dense canopy, high-friction terrain, reduced solar exposure) requires approximately 3,267 Wh per kilometer of travel at 3 km/h average speed. Solar collection is severely reduced by canopy cover; battery discharge exceeds generation on traverse days. Extended stationary charging periods (2–3 days minimum) are required after each forest segment.

Alpine scree traverse (high-friction surfaces, steep gradient, variable solar exposure at high elevation, clear sky conditions) requires approximately 7,600 Wh per kilometer of travel at 2 km/h average speed. Power budget is critically constrained; daily consumption may marginally exceed solar generation even under clear conditions. Battery degradation occurs unless traverse is interrupted with stationary charging periods every 1–2 days.

Canyon passage (extreme-friction terrain, tight gradient, full canopy shade, low solar angles) requires approximately 12,400 Wh per kilometer of travel at 1.5 km/h average speed or slower. Solar collection is negligible; battery discharge is severe and unsustainable except for brief high-priority transit missions. Canyon segments must be planned as battery-depletion events; systems enter degraded operational mode immediately upon entry.

Recharging occurs only during stationary periods. Solar collection rate, panel area, battery state, and seasonal conditions determine charging time and route planning constraints.

*Calculated assuming 10-hour effective solar collection window at rated output; actual duration depends on seasonal variation of collection hours.

Solar collection window by season: Northern corridor experiences 7–8 hours of useful collection (sun angle above 30°) during winter months, increasing to 12–14 hours during summer peak. Central corridor maintains 10–12 hours year-round. Southern corridor achieves 11–13 hours minimum during winter, extending to 14–15 hours in summer. Collection window shifts earlier in summer (sunrise collection begins at 05:30–06:00) and later in winter (collection extends to 16:30–17:00).

Route planning implications: Segments with high canopy coverage (forest, dense brush areas) reduce solar generation below consumption rate and require pre-planning of stationary charging periods. A segment requiring 2 days of traverse through continuous forest must be preceded by a 2–3 day stationary charging period to build reserve capacity. Canyon passages with minimal solar exposure cannot be sustained continuously; a 1-day canyon passage requires 1 full day of stationary charging on either end. Route sequencing should alternate high-consumption (low-solar) terrain with open terrain that permits simultaneous charging and traverse.

Charging optimization: Battery charging rate is maximum during low battery state (0–50% capacity) and decreases as battery approaches full capacity to prevent overstress. Charging at the minimum reserve threshold (20%) to 80% capacity requires 60–70% of the time necessary to charge fully from reserve to 100%, with reduced stress on battery chemistry and extended cycle life. Route planning that targets 80% capacity as a practical "full" state and 20% as the operational minimum extends total battery cycle life by 30–40% compared to 0–100% cycling.

Power generation compromise (panel damage, extended overcast, dense canopy) requires procedural response to maintain operational continuity. System redundancy is achieved through load reduction priority and core function preservation.

Panel damage recovery: Single-panel damage or failure (crack, reduced output) on a multi-panel system reduces collection capacity proportionally but does not prevent traverse. A system with four 1.0 m² panels operating at 3,200 W combined output, with one panel damaged (output reduced to 20%), loses approximately 20% collection capacity. Traverse continues at reduced charging rate; stationary charging periods are extended proportionally. If panel damage is repairable (panel cleaning, minor seal failure), perform repair immediately; if damage is structural (cracked glass, broken connection), continue traverse and plan major repair during planned stationary period of 3+ days.

Extended overcast conditions (multi-day cloud cover) reduce solar collection to 40–60% of clear-sky output. If overcast conditions persist and battery charge approaches 50%, activate load shedding protocol: reduce sensor update frequency (LIDAR to 2 Hz instead of 10 Hz), disable non-critical lighting, reduce navigation compute to essential path-finding only. This reduces total consumption by approximately 40% and extends battery life by equivalent amount.

Canopy cover management: When entering dense canopy (forest, urban canyon, narrow passage), solar collection drops below consumption rate immediately. Do not enter high-canopy terrain unless battery charge is at 80% or higher. Calculate estimated traverse time through canopy zone; if traverse time exceeds estimated battery duration at current load, reduce consumption preemptively by shedding non-critical loads before entering canopy.

Priority load shedding sequence (executed in order when battery capacity drops below indicated threshold):

• 80% battery: No action required. Normal traverse.
• 50% battery: Reduce lighting systems to essential navigation only. Reduce LIDAR update frequency to 2 Hz. Disable non-essential data logging.
• 30% battery: Shut down acoustic detection system. Reduce navigation compute to essential waypoint following only (no predictive route planning). Reduce thermal management to minimum.
• 20% battery: Shut down communication subsystem except emergency beacon. Reduce radar to 1 Hz update. Enter "traverse survival" mode: locomotion at minimum speed to preserve momentum and reduce load.
• 10% battery: Shut down all non-essential systems. Maintain only: LIDAR (1 Hz), basic navigation compute, thermal management (minimum), emergency beacon. Prepare to halt and enter stationary mode.
• 5% battery: Halt immediately. All systems except navigation computer and emergency beacon powered down. Wait for solar collection and stationary charging.

Minimum operational configuration: Core systems that cannot be disabled are navigation compute (essential for route continuity), LIDAR obstacle detection (safety-critical), and emergency communication beacon (system status transmission). These three systems consume approximately 55 W combined and can operate for 36+ hours on 2,000 Wh reserve capacity, allowing survival operation during extended power-generation failure.

Recovery procedure after power constraint: After battery charge is recovered to 80% through stationary charging, sequentially restore systems in reverse order: restore thermal management and reduce-frequency sensors, restore communication subsystem, restore standard sensor update rates, restore full navigation compute. Total restoration to full-system operation requires approximately 2 hours of charging time beyond reaching 80% capacity.