A hilltop repeater is the least forgiving solar site there is: a continuous 24/7 load, no shade for maintenance, constant wind load on the array, and lightning exposure that will find any weakness in the earthing. Design decisions here are dominated by reliability engineering, not by energy arithmetic.
Load profile
| Element | Typical draw | Notes |
|---|---|---|
| Repeater / radio unit | 10-60 W continuous | Steady, does not sleep |
| Microwave or link radio | 8-30 W continuous | Higher in transmit-heavy duty |
| Router / management unit | 3-10 W | Continuous |
| Cabinet fan or heater | 5-30 W intermittent | Can exceed the radio in extreme climates |
| Beacon / obstruction light | 2-10 W at night | Mandatory on tall masts |
A 40 W continuous repeater plus management and cooling lands around 1.2-1.8 kWh/day. That is a genuinely large off-grid system — expect 1-2 kWp of array and a battery bank measured in tens of kilowatt-hours.
Autonomy expectations differ from monitoring sites
A monitoring station can lose a day of data and recover. A repeater that goes down cuts an entire link, so operators typically demand 5-7 days of autonomy and sometimes dual battery strings so one can be serviced without interrupting service. Plan the enclosure around that, not around the minimum.
Wind load and array mounting
Hilltops see sustained wind that a rooftop design never experiences. Two practical responses: keep the array low and close to the ground or structure where possible, and use a mounting system rated well beyond the local design wind speed. A panel that lifts in a storm takes the cabling and sometimes the mast with it.
- Prefer several smaller panels over one large one — lower individual sail area, easier replacement
- Torque fixings to spec and re-check after the first storm season
- Route array cables in conduit fixed at close intervals
Lightning
This is where hilltop systems are lost. A complete protection scheme includes:
- Air termination and a bonded mast, not a floating one
- DC surge protective devices on the array side of the controller
- Coax surge arresters on every RF feed at the entry point
- A single bonding point tying DC earth, RF earth and structure earth together
- Short, straight earth conductors — bends increase impedance
Battery temperature
Hilltop cabinets swing from below freezing at night to 50 °C in sun. Lithium with low-temperature charge protection plus a shaded, insulated cabinet is the workable combination; lead-acid will need oversizing to survive the same swing.
FAQ
How much solar power does a telecom repeater need?
For a 40 W continuous load, roughly 1.5-2.5 kWp of array with 5-7 days of autonomy, depending on the local worst-month sun hours and cabinet cooling load.
Can a repeater run on a small panel and battery?
Only for very low-power links (a few watts). A 24/7 radio load quickly exceeds what a compact kit can sustain through cloudy periods.
Why do hilltop systems fail after storms?
Almost always surge damage through the RF feed or array, or mechanical failure of the mounting. Both are design issues, not equipment failures.
We supply complete off-grid power for remote telecom and monitoring sites. Talk to the engineering team or see remote site power design.