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UPS battery backup

Minutes: ride through a flicker, or shut down cleanly.

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Portable power stations

Hours: a charged battery, with no fuel to store.

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Portable generators

Days: as long as the fuel lasts, always outdoors.

57 guides

Best picks and comparisons

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UPS battery backup

Minutes: ride through a flicker, or shut down cleanly.

Portable power stations

Hours: a charged battery, with no fuel to store.

Portable generators

Days: as long as the fuel lasts, always outdoors.

Guide 39 · UPS

Choosing a battery backup (UPS) for a fiber ONT and router

Fiber carries light, not electricity, so your ONT box goes dark when the power does. A UPS sized to your own ONT and router load can keep your connection running through short outages.

Updated Drafted and checked with AIFact-checked by the HoldBackup editorial team How this guide was madeBased on manufacturer specs and owner reports, not HoldBackup's own testing.

On this page
  1. Why the ONT needs its own backup power
  2. Find your own load first
  3. Turn your load into runtime
  4. Outlets and placement
  5. Batteries, alarms, and upkeep
  6. Sources

Affiliate disclosure: some store links on HoldBackup are affiliate links. If you buy through one, HoldBackup may earn a commission at no extra cost to you. As an Amazon Associate I earn from qualifying purchases. How HoldBackup makes money

The verdict

Buy a UPS with enough battery-backed outlets for both your ONT and your router, and size it by reading the maker's runtime chart at the combined load you measured yourself.

See the store link

What we check

  • Battery-backed outlets for both the ONT and router
  • Runtime at your own measured load
  • Outlet spacing for bulky power bricks
  • Output waveform your devices' makers accept
  • Replaceable battery and warranty terms
  • Alarm you can mute
Compact tower UPS: upright unit on small feet with a narrow front display strip, a lit round power button and two vent slots on its side

Drawing of backup power equipment.

Store link UPS

CyberPower CP1500PFCLCD PFC Sinewave UPS Battery Backup and Surge Protector

One listing to compare. Check its specs against the list above before you buy.

Maker's US pageCyberPower's US page lists it with Purchase Online.cyberpowersystems.com Checked

What owners reportOwners report it works with home server and NAS shutdown software and lasts for years with fresh batteries. Forum owners also say the batteries can give out with no warning from the unit.TrueNAS forum, Unraid forum, The FPS Review forum Checked

PriceAmazon sets it, and it changes. The button takes you to today's price.

Store linkPaid link

The unit named above, on Amazon.

Check price on Amazon

HoldBackup earns a commission if you buy through this link. Amazon sets the price.

Why the ONT needs its own backup power

Old copper phone lines carried a small amount of power from the phone company. Fiber does not. The ONT, the box where the fiber line ends inside or outside your home, runs on household power through its own adapter. When that power stops, so does your connection, even if your router has a battery.

You need both pieces powered: the ONT that talks to your provider and the router that serves your devices. If either one goes dark, you lose internet.

A UPS keeps power flowing only on your side. Whether service continues also depends on your provider's equipment in the neighborhood, so ask your provider how their network handles outages.

Find your own load first

Draws vary widely between models, so use numbers from your own equipment. Each power brick has a label with its output rating, which is a maximum rather than what the device uses all the time. A plug-in watt meter gives you the real figure while the ONT and router are running normally.

Add up everything you plan to keep on battery. Include a network switch, mesh node, or cordless phone base only if it must stay up during an outage, because every extra device shortens runtime.

  • Read the output rating on the ONT and router power bricks
  • Measure actual draw with a plug-in watt meter for a more accurate number
  • Add only the devices you truly need running

Turn your load into runtime

The model name and headline rating on a UPS describe its maximum capacity, not how long it will last. Small networking loads use only a fraction of that capacity, which is why runtime charts matter more than the big number.

For example, if your ONT and router together measure 20 watts on a watt meter, find 20 watts on the maker's runtime chart and read the minutes listed there. Compare that figure with how long your typical outages last.

If you need many hours rather than a short bridge, a portable power station may suit you better than a UPS.

Outlets and placement

Most UPS units split their outlets into two groups: battery-backed with surge protection, and surge-only. Plug the ONT and router into the battery-backed side. Devices on the surge-only side lose power in an outage.

Power bricks can block neighboring outlets, so check the outlet layout and spacing against your adapters. Short extension leads made for bricks can help.

The ONT is often mounted in a garage, basement, or utility closet, while the router sits elsewhere. If they are far apart, you may need two smaller units or a change in where the router lives. Plug the UPS straight into a wall outlet rather than into a power strip or extension cord.

  • Confirm the number of battery-backed outlets
  • Check spacing for wide adapters
  • Keep the UPS somewhere dry and ventilated, within its rated temperature range

Batteries, alarms, and upkeep

UPS batteries wear out with age and use. Check whether the battery is user-replaceable, which replacement part the maker lists, and what the warranty covers for the battery versus the unit.

A UPS beeps when it switches to battery. If the unit sits near a bedroom, check that the alarm can be muted. Some units have a display that shows load and estimated runtime, which makes it easy to confirm the ONT and router are on the backed-up side.

The linked CyberPower PFC Sinewave UPS is one option to compare. Check its spec sheet, outlet layout, runtime chart, and warranty against your own measured load before buying.

Sources

Recorded AI check: Oct 12, 2026. The sources below may include later additions. AI checks compare factual numbers and checkable claims with web sources; they do not verify every statement.

Best UPS battery backup for a home and APC vs CyberPower compare units from the makers' numbers. Every guide in this class is in UPS battery backup.

How this guide was made

  1. Drafted and checked with AI. An AI model wrote the draft from the guide's topic. A second AI pass looked for factual numbers to check against web sources. This does not verify every statement. A draft that fails the check is held for review.
  2. Fact-checked by the HoldBackup editorial team. On , a person on the HoldBackup editorial team reviewed this guide against its sources. That is a review of the writing, not a test of any unit.
  3. General guidance only. No prices, rankings, or test results, because we have none to back them. Check any number against the maker's own spec sheet.
  4. No lab tests, and we say so. HoldBackup has not run any unit named here.
  5. The store link is not a pick for this guide. It goes to a unit in this product class that this guide does not review. Check it against the list above before you buy.
  6. Labelled store links. A store button goes straight to Amazon with HoldBackup's affiliate tag. HoldBackup counts the click. A live button carries a "paid link" label, and the disclosure sits above the first one on every guide.

Questions

My provider gave me a battery unit for the ONT. Do I still need a UPS?

Possibly. Ask your provider whether that battery keeps internet data running or only phone service, and for how long. It also does not power your router, so you would still need backup for the router.

Will my internet work if the whole neighborhood loses power?

Only if your provider's equipment outside your home stays powered. A UPS keeps your ONT and router running, but it cannot help if the provider's network is down. Ask your provider how they handle outages.

Does the output waveform matter for an ONT and router?

Many small adapters run fine on either type of output, but some power supplies work best on sine wave output. Check your devices' manuals or makers if you are unsure. The linked unit's title lists sine wave output.

How do I know which outlets are battery-backed?

The UPS labels them on the case and in the manual. Plug the ONT and router into those outlets, then unplug the UPS from the wall briefly to confirm both stay on.

Where does the price button go?

Straight to Amazon. Amazon sets the price and availability, and both can change.

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