5G rollouts push radio-site power consumption well above 4G levels, and the -48VDC power system is usually the first bottleneck an installer meets. This guide walks through the four sizing decisions for a 5G base station power system: load calculation, rectifier capacity with N+1 redundancy, battery backup sizing, and hybrid/temperature strategy. Product examples link to modules and cabinets available in our catalog; all figures below are illustrative and should be replaced with your equipment datasheets during detailed design.
Step 1: Calculate the site load
Start from the equipment list. A 5G site typically includes one or more active antenna units (AAU), a baseband unit (BBU), transmission equipment and auxiliaries. Take each item’s power draw from its datasheet — do not rely on generic assumptions for 5G radios, whose consumption varies strongly with configuration and traffic.
Illustrative frame: an AAU at ~1,100 W + BBU at ~350 W + transmission/auxiliaries at ~250 W gives a DC load of about 1,700 W. With a -48V bus and a wiring/rectifier efficiency of ~92%, the required rectifier output current is roughly 1,700 / (48 × 0.92) ≈ 39 A. Size for peak, not average: 5G radios have traffic-dependent peaks that must not trip your budget.
Step 2: Rectifier capacity and N+1 redundancy
Divide the total load current by the rated current of your chosen rectifier module, then add at least one spare module:
- Using 50A-class modules (e.g. Huawei R4850N2, ZTE ZXD2400 platform): a 39 A load needs 1 working module — still install N+1 (2 modules) so a failure never interrupts service.
- Using 62.5A-class modules (Vertiv R48-3000E3, Eltek Flatpack2 48/3000 HE): the same load is covered by 1 module + 1 redundant.
- Leave headroom for the next expansion step: a cabinet like the Huawei ETP48200-C5A1 (200A) or Vertiv NetSure 731 A41-S1 (200A) hosts additional modules as the site grows.
For macro sites running 4G+5G together, the load often lands at 3–6 kW; a 200A cabinet with 4–5 modules plus redundancy is then a natural fit. See the 48V cross-reference chart for module-to-cabinet mapping.
Step 3: Battery backup sizing
Battery capacity in amp-hours follows from the autonomy target:
C (Ah) ≈ (P_load × t_backup) / (V_float × DoD × η_batt)
Illustrative example: 5 kW load, 3 hours autonomy, 48V float, 80% depth of discharge, 95% battery efficiency → C ≈ 5,000 × 3 / (51.6 × 0.8 × 0.95) ≈ 385 Ah. Choose the next standard string size above the result — for example two 12V/200Ah VRLA strings in series-parallel, or an equivalent lithium pack. Lithium batteries tolerate daily cycling and high temperature better than VRLA; VRLA remains the budget default for low-cycling sites.
Step 4: Hybrid power and temperature strategy
- Weak-grid or off-grid sites: pair the rectifier system with solar input through a hybrid-capable cabinet; the NetSure 731 A41-S1 publishes solar-controller compatibility and sleep-mode energy saving for hybrid PV sites.
- Outdoor cabinets: verify the operating temperature range — the NetSure 731 A41 is specified from -40°C to +65°C, which removes the need for active cooling in many climates.
- Indoor rooms: high-density cabinets like the ETP48200-C5A1 keep maintenance front-accessible in 19-inch racks.
- Small cells and CPE-style sites: a 30A shelf such as the Huawei ETP4830-A1 with a single 2000W–3000W module covers compact loads.
Delivery checklist
- Load sheet signed against datasheets, sized for peak traffic.
- N+1 rectifier modules confirmed physically installed, not just provisioned.
- Battery strings fused, with DoD settings entered in the supervision controller.
- Monitoring (CAN/RS485/Ethernet) pointed to the NOC; alarm thresholds tested.
- Cabinet temperature derating verified against the worst ambient month.
How many rectifier modules does a 5G site need?
It depends on the measured load, not the site type. Divide peak DC load by the module’s rated output current and add one spare module: for example, a ~3.9 kW site on 50A modules needs 1 working + 1 redundant module; a 4G+5G macro site at 6 kW needs about 3–4 working modules plus redundancy on a 200A cabinet.
How much battery backup is typical for a 5G base station?
Operators commonly target 3–4 hours of autonomy for macro sites and less for small cells. Using the formula C ≈ (P_load × t) / (V_float × DoD × η), a 5 kW site with 3 hours of autonomy lands around 385–400 Ah at 48V; replace the assumptions with your actual load and battery datasheet.
Can a solar-hybrid site use the same -48V rectifier cabinet?
Yes, if the cabinet supports hybrid energy features. The Vertiv NetSure 731 A41-S1 documents solar-controller compatibility and sleep-mode savings, and the Huawei ETP48 family includes solar-ready variants; confirm the feature set with the datasheet before ordering.
Does BS Comtec supply complete 5G power kits?
Yes. BS Comtec supplies rectifier modules, embedded cabinets and battery connectivity from its Singapore stock — from 30A small-cell shelves to 200A macro cabinets — with 1-piece minimum order, 24–48 hour dispatch and configuration advice on request.