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Keep your fibre online during load-shedding in Stellenbosch: DC-UPS sizing guide

Fibre down during load-shedding? Learn how to size a DC-UPS for your ONT + router, keep Wi-Fi running, and avoid downtime in Stellenbosch.

· Digissential Team · 2 min read

fibre loadsheddingdc upsstellenboschwifi routerbackup power

TL;DR: Fibre goes down during load-shedding because ONTs and routers lose power. A small DC-UPS (≈100Wh) keeps Wi-Fi alive for 4 hours in Stellenbosch rentals and offices.

Why fibre fails during load-shedding

Even if your ISP’s network stays online, your ONT (fibre box) and Wi-Fi router both shut down without backup power.
This leaves students offline during exams and SMEs unable to process card payments.

How to size your DC-UPS

  1. Check device labels
    ONT: 12V × 1A (≈12W)
    Router: 12V × 1A (≈12W)
    → Total ≈24W

  2. Calculate runtime
    Load (24W) × Hours (4h) = 96Wh

  3. Add headroom
    Choose a UPS with at least 20% more capacity → ~120Wh unit.

  4. Choose DC vs AC UPS

    • DC-UPS: efficient, compact, ideal for ONT/router.
    • AC UPS: powers full PCs, but bulkier/less efficient for routers.

  5. Plug & play tips (rentals)

    • Keep old power adapters in case you move out.
    • Label cables for ONT vs router.
    • Test after installation — don’t wait for load-shedding.

Price bands in Stellenbosch (ZAR)

  • Entry-level (2–3h runtime, lead-acid): R800–R1,200
  • Mid-range (4h runtime, lithium DC-UPS): R1,500–R2,500
  • High-capacity (8h runtime or dual routers): R3,000+

When to call Digissential

  • Fibre keeps dropping even though UPS is installed.
  • Router overheats or restarts during load-shedding.
  • You need stable Wi-Fi for POS systems in cafés/wine farms.

We provide:

FAQs

Q: Why does my fibre drop during load-shedding?
A: The ONT (fibre box) and router both need power. Without a UPS, they shut off as soon as Eskom cuts power.

Q: What size DC-UPS do I need?
A: Most Stellenbosch setups use ~20–25W. For 4 hours runtime, aim for 100Wh capacity.

Q: What’s the difference between AC and DC UPS?
A: DC-UPS units run more efficiently for ONTs/routers (no AC→DC conversion). AC UPS is bulkier and better for PCs.

Q: How much do DC-UPS units cost in Stellenbosch?
A: Entry-level DC-UPS: R800–R1,200. Mid-range: R1,500–R2,500. High-capacity/lithium: R3,000+.

Q: Can Digissential install this for me?
A: Yes. We set up UPS units, optimise Wi-Fi, and offer remote/device health checks to prevent downtime.

Compliance & trust:

External references:

Updated on 2025-09-05.