How big UPS do I need for a WiFi router?
To power a WiFi router, a UPS with 300–500 VA capacity is typically sufficient, assuming a router consumes 5–20W. For example, a 300VA/180W UPS with a 12V 7Ah battery provides 1–2 hours of runtime. Pro Tip: Add 25% buffer to account for modem or signal booster loads. Use this formula: UPS VA = (Router Wattage / Power Factor) × 1.25 (standard power factor = 0.6–0.7).
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How do I calculate UPS runtime for a router?
Runtime depends on battery capacity and load. For a 12V 7Ah battery and 15W router: Runtime ≈ (7Ah × 12V × 0.9 efficiency) / 15W = ~5 hours. Pro Tip: Use lithium-ion batteries for 3× longer runtime vs. lead-acid.
To calculate precisely, start by measuring your router’s actual wattage with a power meter. If it draws 10W, a 300VA UPS with 0.6 power factor delivers 180W max—far above the router’s needs, allowing room for additional devices. But what if you add a modem or security camera? A 500VA unit (300W) would extend runtime to 3–4 hours. Transitionally, lithium batteries like LiFePO4 offer 80% depth of discharge vs. 50% for lead-acid, doubling usable capacity. For example, a 12V 10Ah LiFePO4 pack paired with a 300VA UPS can sustain a 15W load for 7.2 hours. Always check UPS compatibility before upgrading batteries.
What battery type is best for router UPS systems?
Lithium-ion (LiFePO4) outperforms lead-acid with 2,000+ cycles and 10-year lifespans. A 12V 5Ah LiFePO4 battery weighs 1.5kg vs. 3kg for equivalent lead-acid.
Lead-acid batteries, while cheaper upfront ($20–$50), require frequent replacements every 2–3 years. Lithium options like LiFePO4 ($80–$150) last 5–10 years and tolerate deeper discharges. For instance, a 12V 10Ah LiFePO4 battery in a 500VA UPS can power a 20W router/modem combo for 5.4 hours (10Ah × 12V × 0.9 / 20W). Transitionally, lithium’s flat discharge curve maintains stable voltage, preventing router reboots during brownouts. Pro Tip: Opt for UPS systems with adjustable voltage cutoffs to maximize lithium battery life. Real-world example: CyberPower CP900HG provides 85 minutes for 50W loads and works with external lithium packs.
| Battery Type | Cycle Life | Cost per kWh |
|---|---|---|
| LiFePO4 | 2,000+ | $400–$600 |
| Lead-Acid | 300–500 | $150–$250 |
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FAQs
No—quality UPS units with pure sine wave output (e.g., APC Back-UPS) prevent voltage spikes that could harm sensitive electronics.
How often should I replace UPS batteries?
Lead-acid: Every 2–3 years. Lithium: Every 5–10 years. Replace if runtime drops below 50% of original capacity.