Use case · Week 2

Cable modem / fiber ONT — blackout Wh honesty

Keep the ISP handoff alive — cable modem or fiber ONT is often a tiny continuous draw, but if this brick dies, nothing upstream matters. Distinct from full Wi‑Fi / router + mesh stacks; also vs Starlink, smart-home hub, and WFH outage kits.

Modem / ONT watts — the tiny load that unlocks everything

  • Often tiny continuous draw. Many cable modems and fiber ONTs pull ~8–20 W steady. A compact ~300 Wh station can cover a workday+ of modem-only (estimates). The honesty issue is remembering to power this brick first.
  • Distinct from Wi‑Fi / router backup. That guide covers modem + router + mesh satellites as a stack — Wi‑Fi / modem backup. This page is the ISP handoff alone: cable modem, DOCSIS gateway WAN side, or fiber ONT / NID wall brick.
  • ISP street power still required. Your battery does not revive a dark neighbourhood node or CMTS/OLT. Station power only helps when the last-mile plant is still lit.
  • Combo ISP gateways. If modem + Wi‑Fi share one box, size the whole gateway (~15–30 W+) and follow the mesh caveats on the Wi‑Fi page. Pure ONT + separate router: power both.
  • Adjacent stacks: Starlink is a different dish/router budget; smart-home hubs and security cams need the handoff up; WFH desks: work-from-home outage.

Specs from manufacturer pages (checked Oct 2026). Runtime figures are estimates. Not ISP or networking advice — follow modem/ONT and station OEM manuals; UPS-class switchover helps finicky ONTs.

Modem / ONT Wh estimates

Hours ≈ (rated Wh × 0.85) ÷ modem watts · add router/mesh only after the handoff is covered.

Modem / ONT ~10–15 W

Multi-day easy

286 Wh ≈ ~16–24 h · 1 kWh ≈ ~55–85 h usable (est.)

Combo gateway ~20–30 W

Still overnight+

Then escalate to Wi‑Fi / mesh math if satellites matter

Vs Starlink / cams / WFH

Handoff first

Starlink · cams · WFH all assume this brick lives

Comparison: modem / ONT honesty

Filter by ISP-handoff fit. Prefer UPS-class switchover if flickers reboot the ONT.

Model Wh · UPS Est. modem / ONT Vs Wi‑Fi / Starlink / WFH Approx. USD
EcoFlow RIVER 3 Plus Compact 286 Wh · UPS <10 ms ~16–24 h @ 10–15 W (est.) Ideal modem-only shelf kit; mesh → Wi‑Fi page. ~$180–300
Anker SOLIX C300 288 Wh ~16–24 h @ 10–15 W (est.) Closet ONT brick; watch continuous W on fat gateways. ~$200–280
Jackery Explorer 1000 v2 Quiet 1,070 Wh · UPS <20 ms Days of modem-only (est.) Leftover Wh for router / WFH desk. ~$499–589
BLUETTI Elite 100 V2 1,024 Wh · UPS ≤10 ms Days of ONT (est.) Fast switchover for finicky fiber ONTs. ~$380–500
Anker SOLIX C1000 Expand 1,056 Wh · UPS <20 ms Modem trivial; expand for multi-day house kit Add hub / cams after handoff. ~$400–600
EcoFlow DELTA 3 Plus 1,024 Wh expandable · UPS <10 ms Modem Wh is noise; leftover for lights / fridge Vs dish budgets: Starlink backup. ~$600–900+
BLUETTI AC200L 2,048 Wh Overkill for modem alone; great shared house battery Still distinct from full mesh stack sizing. ~$800–1,100

QuietWatt is independent. Cross-link: Wi‑Fi / modem backup · Starlink backup · smart-home hub · security camera · WFH outage. Estimates only — ISP uptime is outside any battery’s control.

Where to buy (affiliate placeholders)

Tracked affiliate links will replace these placeholders once QuietWatt is enrolled in each program. Until then, use the official product URLs in the table above.

Buy via EcoFlow Buy via BLUETTI Buy via Anker Buy via Jackery Buy via Amazon

Placeholder anchors: #aff-ecoflow, #aff-bluetti, #aff-anker, #aff-jackery, #aff-amazon.

Sources