Skip to main content

Building Solar Mountain Repeaters for Armenia

Autonomous mountaintop and rooftop repeaters form the backbone of the Armenian mesh network, bridging Yerevan with surrounding valleys, Lake Sevan, and mountain passes.

🏔️ Environmental Challenges in Armenia​

Deploying an autonomous repeater in Armenia requires accounting for:

  • Sub-Zero Winters: Winter temperatures on Mount Aragats, Geghama mountains, and northern passes drop below -20°C to -30°C.
  • Lithium Charging Limitations: Standard Lithium-Ion (Li-Po/Li-Ion) batteries cannot safely be charged below 0°C without risk of permanent damage or internal dendrite shorting.
  • Heavy Snow & Ice Accumulation: Snow loads and ice rime can block solar panels and bend fragile antennas.
[ 5W - 10W Solar Panel (Tempered Glass / IP67) ]
                  │
                  ▼
[ RAK Wireless RAK4631 (nRF52840) ]
                  │
                  ▼
[ LiFePO4 Battery or Low-Temp Li-Ion ] (18650 / 21700)
                  │
                  ▼
[ 868 MHz Tuned Fiberglass Antenna (3 - 5.8 dBi) ]

1. Electronics​

  • Board: RAK Wireless WisBlock (RAK4631 + RAK19007). Idle power consumption is under 15 mA, allowing a single 3000 mAh battery to survive over 8 days of total darkness or blizzard coverage.
  • Firmware Role: Configure as ROUTER (or ROUTER_CLIENT if local Bluetooth connection is needed). Note that the legacy REPEATER role is deprecated in modern Meshtastic firmware.

2. Battery Selection​

  • LiFePO4 (Lithium Iron Phosphate): Far safer and handles wider operating temperature ranges (-20°C to +60°C).
  • Cold-Weather 18650 / 21700 Cells: Look for cells rated for low-temperature discharge. If using standard Li-Ion, ensure thermal insulation inside the enclosure.

3. Solar Panel​

  • Rating: 5V / 6V with 5W to 10W output.
  • Angle: Mount the panel at approximately 45° to 60° tilt facing south. This maximizes winter sun capture when the sun is low on the horizon, while allowing snow to slide off easily.

4. Weatherproof Enclosure​

  • IP67 or IP68 rated polycarbonate or fiberglass enclosure.
  • Use waterproof cable glands (PG7 / PG9) with silicone grease.
  • Include a Gore-Tex breathing vent (e.g. Amphenol / Schreiner vent) to equalize pressure without allowing moisture ingress, preventing internal condensation.