Application guide · Telecom power
Solar for Telecom Towers: 48 V DC Base Station Power Design
Solar for telecom tower sites is a different problem from solar for a house: the load never sleeps, the site is usually a lease with no grid, and the penalty for downtime is measured in dropped calls across a whole district. A typical 4G macro site in Nigeria or the Philippines draws 600–1,200 W continuously, which is 14–29 kWh a day — five to ten times a village household.
Typical site load
600–1,200 W continuous
Array
5–10 kWp
Battery autonomy
8–12 h (25–40 kWh)
This page sets out how we size solar for telecom tower sites: the load audit that separates rectifier, radio and cooling, the 48 V DC architecture that avoids double conversion, the array and battery combinations that hold a site through an 8–12 hour outage, indicative EXW cost bands, and the site rules — theft, tilt, grounding, generator handover — that decide whether the hybrid actually saves diesel.
The three costs a BTS site carries
Every off-grid tower carries three costs at once: diesel, diesel logistics and downtime. A 900 W site running a 20 kVA generator 24/7 burns roughly 5–7 litres an hour at partial load, which is 40–55 litres a day — and in northern Nigeria or the Philippine islands the fuel truck is the single largest failure mode, not the generator itself.
The second problem is architecture. Many sites were built as AC-coupled: the rectifier converts 230 V AC to −48 V DC, so a solar inverter has to make AC first and the rectifier turns it back into DC. Every conversion costs 6–10%, and the rectifier keeps running at low load where its efficiency is worst. A DC-coupled array feeding the −48 V bus directly removes one conversion and lets the existing rectifier become the backup rather than the primary source.
The third is thermal and theft. A sealed outdoor cabinet in Lagos reaches 50 °C internally, which halves LFP calendar life; and an unsecured ground mount loses panels within months. Both are design decisions, not maintenance problems.
- ✓Diesel at 40–55 litres a day per site plus a fuel-logistics chain that fails silently
- ✓AC-coupled architecture wasting 6–10% through double conversion
- ✓Rectifier running at 20–30% load, where efficiency drops below 85%
- ✓Battery cabinet at 50 °C internal, halving LFP service life
- ✓No remote monitoring, so a failed string is discovered by a dropped-cell complaint
Typical BTS load values
Audit the site in DC amps at the −48 V bus, not in AC watts at the meter. The table below is a 4G macro site with three sectors and a microwave link; 5G sites add 300–600 W per sector and change the array size by 40%.
| Item | Power | Hours | Daily energy |
|---|---|---|---|
| BBU + 3 × RRU (4G, 3 sectors) | 450 W | 24 h | 10.8 kWh |
| Microwave / fibre CPE link | 60 W | 24 h | 1.4 kWh |
| Rectifier and DC losses (8%) | 45 W | 24 h | 1.1 kWh |
| Cabinet cooling (thermostat fan / AC) | 250–600 W | 8–14 h | 3.0–8.4 kWh |
| Site lighting, alarms, door sensor | 30 W | 12 h | 0.4 kWh |
Total for the reference site: 17–22 kWh a day, or 350–460 Ah at 48 V. Cooling is the variable that gets ignored: replacing a 600 W cabinet air-conditioner with a filtered fan and a shaded cabinet can cut daily energy by 6 kWh, which is one whole battery string.
Recommended configurations
Sizing rule we use: array = daily kWh ÷ (worst-month peak-sun hours × 0.72), battery = load × autonomy hours. The 0.72 derate covers dust, temperature and DC cabling on a tower site, where panels are rarely washed.
| Tier | PV array | Battery | Power electronics | Serves |
|---|---|---|---|---|
| T1 — 5G micro / small cell | 1.5–2 kWp (8–10 × 200 W) | 51.2 V 200 Ah (10.24 kWh) | 48 V MPPT 60 A + existing rectifier | 400 W load, 6–8 h autonomy |
| T2 — 4G macro, 3 sectors | 5 kWp (25 × 200 W) | 2 × 51.2 V 400 Ah (40.96 kWh) | 48 V MPPT 100 A + 48 V rectifier 100 A | 900 W load, 10–12 h autonomy |
| T3 — 5G macro + AC cooling | 10 kWp (50 × 200 W) | 4 × 51.2 V 400 Ah (81.9 kWh) | Dual 48 V MPPT 100 A, generator interface | 1.8 kW load, 12 h autonomy, genset backup |
Keep the generator. Solar for telecom tower sites is almost never sized for 100% availability in the rainy season; the economic optimum is 85–95% solar fraction with a genset that starts automatically below 45 V or after two low-yield days. Trying to hit 100% with battery doubles the capital cost for a handful of nights a year.
Indicative cost ranges (USD, EXW Ningbo)
The bands below are for the DC power plant only: modules, mounting, MPPT, LFP packs and the outdoor cabinet. They exclude civil works, tower strengthening, freight, installation and commissioning, which typically add 20–35% on a remote site.
| Item | Specification | Indicative range |
|---|---|---|
| T1 small cell kit | 2 kWp PV · 10.24 kWh LFP · 48 V MPPT 60 A | USD 4,200 – 5,400 |
| T2 macro site kit | 5 kWp PV · 40.96 kWh LFP · MPPT + rectifier | USD 11,800 – 14,900 |
| T3 5G macro kit | 10 kWp PV · 81.9 kWh LFP · dual MPPT | USD 23,500 – 29,000 |
| Outdoor IP55 DC cabinet | Insulated, fan-cooled, 19-inch rack | USD 900 – 1,600 |
| Remote monitoring gateway | 4G, SNMP / Modbus, 8 DI | USD 220 – 380 |
- Indicative EXW ranges; final pricing depends on module count, pack tier, cabinet specification and delivery port. Formal quotation follows a site load audit.
- A 20-site rollout typically lands 10–15% below the single-site band because packs and cabinets ship together.
- Diesel comparison: a 900 W site at 45 litres a day and USD 1.10/litre spends about USD 18,000 a year on fuel alone — the T2 kit usually pays back in 18–30 months where fuel logistics are unreliable.
All prices on this page are indicative EXW ranges compiled from current container quotations. They are not a binding offer: freight, duties, installation and exchange rates move, and the final price is issued after we receive your load list and delivery port.
Local adaptation: voltage, climate and certification
Telecom sites are specified by the operator, so the local rules that matter are the ones written into the tower lease and the national type-approval list. These four markets cover most of our BTS shipments.
| Market | Grid & code | Climate | Certification |
|---|---|---|---|
| Nigeria | 230 V / 50 Hz; −48 V DC bus standard, NEMSA for public power | 35–40 °C, harmattan dust, high lightning density | NCC type approval for telecom equipment, SONCAP for imports |
| South Africa | 230 V / 50 Hz; municipal SSEG rules if the site is grid-tied | −5 °C Highveld nights, coastal salt spray, hail | SANS 10142-1, ICASA type approval for radio equipment |
| Ghana | 230 V / 50 Hz; Energy Commission approval | Coastal humidity >80% RH, 1,800 mm annual rain | NCA type approval, EC registration |
| Philippines | 220 V / 60 Hz — 60 Hz rectifiers, not 50 Hz units | Typhoon zone, 250 km/h design wind, 9-month wet season | NTC type acceptance, DOE compliance for energy projects |
Site rules that decide whether the hybrid pays back
Meter the site for seven days first
A clamp logger on the −48 V bus and on the rectifier AC input gives the real load profile. Two sites with the same nameplate can differ by 40% because of cooling settings and air-conditioner age.
Couple DC, not AC
Feed the MPPT output straight onto the −48 V bus and let the rectifier act as backup. This removes one conversion and lets the existing rectifier idle at zero instead of running at 25% load all day.
Set the generator handover thresholds
Start the genset at 46–47 V or after two consecutive days below 60% yield; stop it at 54 V. Without hysteresis the site cycles the generator every few hours and burns more fuel than a pure diesel site.
Secure the array against theft
Tamper-proof bolts, welded frame caps and a 2.4 m fence with a monitored door contact. In several West African markets the panels are the most stolen item on site.
Shade and ventilate the cabinet
A double-skin roof and a filtered fan hold the cabinet 10–12 °C below ambient. If the operator insists on air-conditioning, set it to 30 °C, not 22 °C — the difference is 3–4 kWh a day.
Commission with a load test, not a voltage check
Run the site on battery alone for the contracted autonomy hours and log the discharge curve. A string that sags 3 V early will fail in month eight, not on the day of acceptance.
Hardware for this scenario
These are the modules and 51.2 V packs we ship on BTS orders. Send the site load log and the operator's autonomy requirement and we will return a DC single-line diagram with the array, string and pack count.
DLXN-M10-200W module
The workhorse for a 5 kW BTS array: 25 modules fit a 4 × 2 m ground mount, and the 18 V/200 W mono PERC string keeps DC cable runs short on a tower site.
View specifications →
DLXN-M10-100W module
Used for repeater and microwave-only sites with 300–500 W average load, where a 1.5 kW array is enough and transport to site is by hand.
View specifications →
DLXN-F5400 51.2 V 400 Ah
Two of these in parallel give 40.96 kWh at 51.2 V — the 8–12 hour autonomy band a 900 W BTS site needs, with a 100 A continuous discharge that matches a 48 V rectifier.
View specifications →
DLXN-F5200 51.2 V 200 Ah
The 10.24 kWh step for small cells and 5G micro sites where the load averages 400 W and the site only needs a 4-hour ride-through.
View specifications →
Market pages and next steps
Frequently asked questions
How much does a solar system for a telecom tower cost?
A 4G macro site with a 900 W continuous load needs about 5 kWp of PV and 40 kWh of LFP, which is USD 11,800–14,900 EXW for the DC plant. A small cell or 5G micro site at 400 W is USD 4,200–5,400. Civil works, installation and freight add 20–35%; a fully installed macro site typically lands at USD 16,000–20,000.
How much diesel does a solar hybrid actually save?
A 900 W site running 24/7 on diesel burns 40–55 litres a day. A correctly sized hybrid at 90% solar fraction cuts that to 4–6 litres, or about 90%, and the remaining fuel is mostly generator exercise runs. At USD 1.10 a litre the saving is roughly USD 16,000 a year, which is why payback lands at 18–30 months.
Why 48 V DC instead of AC-coupled solar?
Because the radio equipment already runs on −48 V DC. An AC-coupled system converts DC to AC and back, losing 6–10% twice a day, and forces the rectifier to run at low load where efficiency falls below 85%. A DC-coupled MPPT feeding the −48 V bus removes one conversion and uses the existing rectifier as backup, which also means the site keeps working if the inverter fails.
How many hours of battery autonomy should a BTS site have?
Eight to twelve hours for a grid-absent site with a generator, and 20–24 hours only where fuel delivery is impossible in the rainy season. Beyond 12 hours the marginal battery cost per avoided outage hour rises sharply, and a generator becomes the cheaper reliability layer.
Can the solar array be added to an existing diesel site?
Yes, and it is the most common retrofit we quote. Keep the rectifier and generator, add a DC-coupled MPPT and a 51.2 V pack on the −48 V bus, and set the generator start threshold to 46–47 V. The existing generator then runs only in the wet season, and the site does not need a new AC distribution board.
Send us the site load log
Share the seven-day DC load profile, the operator's autonomy requirement and the nearest port. We will return a single-line diagram, array and pack count, and an EXW price within two working days.
- Email:
- dlxn@dlxnsolar.com
- Delivery ports:
- Durban · Lagos · Tema · Manila
- Basis:
- EXW Ningbo / CIF
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