Constructing a solar-powered repeater
Create an always-on, self-sufficient MeshCore node that extends network reach around the clock using free energy from the sun
The case for solar-powered infrastructure
Positioning a solar repeater at an elevated spot transforms your local MeshCore coverage. Running continuously without battery swaps, these units frequently achieve coverage circles of 5-10 kilometres or beyond.
This practical construction manual guides you through every stage of creating a dependable solar node. Component choices, power maths, weather sealing, and mounting are all covered. Prior soldering experience helps, though beginners can follow along successfully.
Advantages of harvesting sunlight
Perpetual operation
Sunlight plus battery storage delivers continuous function through day and night cycles without human intervention.
Zero running costs
Following the initial outlay, operating expenses vanish entirely. No trailing cables indoors, no impact on household bills.
Location flexibility
Mount on rooftops, outbuildings, fence posts, or trees. Power socket proximity becomes irrelevant.
Grid-independent
Your node stays operational through mains failures. Critical for genuine emergency backup capability.
Valuable learning experience
Gain practical knowledge of photovoltaics, charge control, and outdoor electronics. Transferable skills for other projects.
Network strengthening
Your repeater amplifies coverage for the entire community. A single well-placed unit benefits dozens of other participants.
Components checklist (approximately £150-250)
Full shopping list for this build:
Sizing your panel correctly
Determining adequate panel wattage involves straightforward arithmetic:
Establish daily consumption: Optimised ESP32 averages ~40mA. Multiply by 24 hours: 960mAh daily draw. nRF52 variant: ~15mA × 24h = 360mAh daily.
Convert to watt-hours: 960mAh ÷ 1000 × 5V = 4.8Wh per day. Factor in 50% system losses (clouds, suboptimal angle): 9.6Wh required.
British sunshine reality: Expect 3-4 peak sun hours average (winter: 1-2h, summer: 5-6h). Use 3 hours for conservative planning.
Calculate panel size: 9.6Wh ÷ 3h = 3.2W bare minimum. Recommended: 5-10W panel for adequate margin through winter months.
Battery capacity: Three days autonomy = 960mAh × 3 = 2880mAh. Target 3000-5000mAh minimum (one to two 18650 cells).
Assembly sequence (allow 3-4 hours)
Phase 1: bench testing
Wire everything temporarily on your workbench before permanent assembly. Verify panel charges correctly, battery voltage reads properly, node powers up. Debug now, not after weatherproofing!
Phase 2: permanent wiring
Panel → charge controller → battery → buck converter → ESP32. Use substantial wire gauge (20-22 AWG) for power runs. Verify voltage at each stage with multimeter.
Phase 3: firmware configuration
Disable GPS (unless tracking needed), disable WiFi/BLE, configure TX power 17-20dBm, activate router mode. Flash firmware, conduct range tests. Reference power optimisation guide.
Phase 4: weather sealing
Mount components securely inside IP65 enclosure. Apply silicone around cable glands. Test with hosepipe spray. Add Gore-Tex vent patches to prevent internal condensation.
Phase 5: antenna installation
Position antenna vertically above enclosure. Use L-bracket or pole clamp. Weatherproof connector junction (heatshrink plus self-amalgamating tape). Verify SWR if possible.
Phase 6: panel orientation
For Britain: face due south, tilt 35-40 degrees for year-round optimisation. Ensure no shading from chimneys, trees, or structures. Confirm voltage under sunlight.
Phase 7: deployment and monitoring
Install complete assembly at chosen location. Higher placement equals better coverage. Monitor for 24-48 hours: observe battery charge cycles, confirm node remains online consistently.
Ongoing maintenance
Voltage telemetry
Enable battery reporting in MeshCore settings. Watch via app: voltage drops overnight, recovers during daylight. Persistent decline indicates undersized panel or excessive draw.
Quarterly inspections
Clean panel surface (dust, leaves, bird deposits), examine connections, measure battery voltage. Plan cell replacement after 2-3 years of cycling.
Seasonal variation
Winter brings reduced generation, potentially requiring 1-2 days of battery operation. Acceptable provided recharge occurs during brighter spells. Summer brings surplus.
Solar repeater questions answered
What's the total investment?
Approximately £150-250 all-in. Cheaper than commercial alternatives (£300+) but requires your time and effort. With salvaged components: potentially under £100.
Will this survive British winters?
Yes, with realistic expectations. Winter sees 1-2 peak sun hours versus summer's 5-6. Compensate with oversized panel (10W+), larger battery bank (10,000mAh+), or ultra-efficient nRF52 hardware.
Do I need electrical qualifications?
Not for this project. Basic soldering competence plus multimeter familiarity suffices. This is low-voltage DC work (5-12V), presenting no shock hazard. Follow diagrams carefully, test methodically.
Are there commercial alternatives?
Yes: Seeed SenseCAP series or RAK WisGate solar variants. Higher cost (£300-500) but arrive ready to deploy. DIY saves money and teaches more.
How long do batteries last?
18650 lithium cells: 500-1000 full cycles typically equates to 2-3 years with daily cycling. LiFePO4 chemistry: 2000+ cycles spanning 5-8 years, but heavier and pricier.
What about extended cloudy periods?
That's precisely why battery buffering matters. With 10,000mAh storage plus optimised ESP32 (40mA draw) = 10 days autonomy. Britain rarely sees more than 5 consecutive sunless days.
Build your contribution to the network
A solar repeater represents the ultimate infrastructure gift to your local MeshCore community. Perpetually online, maintenance-free operation, kilometres of extended reach. Time to start building!