Best router battery backup UK (2026): keeping broadband and a digital landline up in a power cut
Most UK homes now get their phone line through the broadband router, so when the power goes, the landline goes with it. A router battery backup, a small uninterruptible power supply (UPS), keeps the router and fibre box running through a short cut. This page compares two kinds: compact 12V units that replace the router's own plug, and mains UPS boxes with UK or IEC sockets. We judge each on the runtime its maker publishes, how it connects and what wears out. We have not run any of these down ourselves, and we say whose figure each number is.
By Tom Calder · Updated 21 October 2026 · 6 products, all price-tracked
Our picks
Photo: AmazonAPC CP12036LI
A single 12V router or fibre box from a household-name brand
as of 21 Oct 2026, 10:37 BST · Details
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.
Photo: AmazonAPC BE650G2-UK
Router, fibre box and a PC or TV on one UK-plug unit
as of 21 Oct 2026, 10:37 BST · Details
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.
Photo: AmazonCyberPower CP1500EPFCLCD-UK
A whole desk of kit, including a mesh system and a NAS
as of 21 Oct 2026, 10:37 BST · Details
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.All 6 compared
| UPS | Type | Capacity | Outputs | Switchover | Price |
|---|---|---|---|---|---|
12V DC mini UPS, lithium-ion · 27.75 Wh · 12V DC, 36W max, 3 barrel tips · Instant (DC pass-through) A single 12V router or fibre box from a household-name brand | 12V DC mini UPS, lithium-ion | 27.75 Wh | 12V DC, 36W max, 3 barrel tips | Instant (DC pass-through) | £60 at Amazon as of 21 Oct 2026, 10:37 BST · DetailsProduct prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.In stockCheck price → |
Our verdictOur verdictResearched APC's own pitch is a small lithium UPS for routers and smart-home hubs, quoting up to 4 hours for an average router and 45 minutes at 80% of its 36W rating. It suits a 12V router or ONT that draws under about 10W, and the three barrel tips cover common plugs. It is the most mainstream option on the page, but it has no 9V or USB output, so it only fits kit that runs on 12V. Best for A single 12V router or fibre box from a household-name brand Good
Worth knowing
Who shouldn't buy it: Don't buy it if your router or fibre box runs on 9V or 5V, or you want to cover several devices; an AC UPS such as the APC BE650G2-UK uses your existing adapters instead. | |||||
AC standby UPS, 650VA/400W · 84 Wh · 6 backed-up + 2 surge-only UK sockets, USB-A · 6 ms typical, 10 ms max Router, fibre box and a PC or TV on one UK-plug unit | AC standby UPS, 650VA/400W | 84 Wh | 6 backed-up + 2 surge-only UK sockets, USB-A | 6 ms typical, 10 ms max | £109.97 at Amazon as of 21 Oct 2026, 10:37 BST · DetailsProduct prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.In stockCheck price → |
Our verdictOur verdictResearched A plug-in UPS that keeps the router's own mains adapter in use, so there is no voltage matching to get wrong. APC lists six backed-up sockets, and runtime at a 20W load is quoted by a retailer at about two hours. It suits a household that wants the router, ONT and a laptop dock or TV box covered together. It is bulkier and less efficient for a lone router than a mini DC unit. Best for Router, fibre box and a PC or TV on one UK-plug unit Good
Worth knowing
Who shouldn't buy it: Don't buy it if you only need to keep one router going and want a compact unit; a mini DC UPS is lighter and wastes less energy. | |||||
AC line-interactive, pure sine, 1500VA/900W · 2 UK + 4 IEC sockets, LCD, USB charging · 4 ms typical A whole desk of kit, including a mesh system and a NAS | AC line-interactive, pure sine, 1500VA/900W | — | 2 UK + 4 IEC sockets, LCD, USB charging | 4 ms typical | £390 at Amazon as of 21 Oct 2026, 10:37 BST · DetailsProduct prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.In stockCheck price → |
Our verdictOur verdictResearched CyberPower describes a pure sine wave line-interactive unit with an LCD, two UK sockets and four IEC sockets. Pure sine output suits power supplies that dislike stepped waveforms. This is the heavy-duty choice on the page for several devices, but it is far larger than a router needs. CyberPower quotes only 10 minutes at half load and 3 at full load, so ask for a low-load runtime figure before you plan around it. Best for A whole desk of kit, including a mesh system and a NAS Good
Worth knowing
Who shouldn't buy it: Don't buy it if you only need a router and fibre box covered; a mini DC UPS does that with far less bulk. | |||||
 AC line-interactive UPS, 1050VA/630W, AVR · 6 IEC C13 sockets (needs UK leads) · 4 ms typical A larger home-office setup with router, NAS and PC | AC line-interactive UPS, 1050VA/630W, AVR | — | 6 IEC C13 sockets (needs UK leads) | 4 ms typical | £95.32 at Amazon as of 21 Oct 2026, 10:37 BST · DetailsProduct prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.In stockCheck price → |
Our verdictOur verdictResearched CyberPower lists 43 minutes at 90W and 14 minutes at 200W for this tower, which makes it a sensible fit for a router, ONT and small NAS together. It has six IEC sockets and automatic voltage regulation. CyberPower quotes a 4 ms typical switchover, and the battery is not user-replaceable. It is overkill if you only need to keep one router online. Best for A larger home-office setup with router, NAS and PC Good
Worth knowing
Who shouldn't buy it: Don't buy it if you only run a router and fibre box; a mini DC UPS is smaller and cheaper to run. | |||||
 AC line-interactive UPS, 700VA/360W, AVR · 84 Wh · 4 IEC C13 sockets (needs UK leads) · 6 ms typical, 10 ms max Budget AC cover for a router and a couple of small devices | AC line-interactive UPS, 700VA/360W, AVR | 84 Wh | 4 IEC C13 sockets (needs UK leads) | 6 ms typical, 10 ms max | £79.57 at Amazon as of 21 Oct 2026, 10:37 BST · DetailsProduct prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.In stockCheck price → |
Our verdictOur verdictResearched APC's cheaper Easy UPS line is a basic tower with four IEC sockets and voltage regulation. Its datasheet quotes about six minutes at a 180W half load, so it is a router-and-ONT unit rather than a PC unit. It suits someone who wants an APC-brand AC unit for modest loads. It has no USB port and only basic indicator lights. Best for Budget AC cover for a router and a couple of small devices Good
Worth knowing
Who shouldn't buy it: Don't buy it if you want a USB charging port or UK sockets built in; the APC BE650G2-UK has both. | |||||
 AC line-interactive UPS, 750VA/410W, AVR · 84 Wh · 4 IEC C13 sockets (needs UK leads) · 6 ms typical, 10 ms max A small home-office desk: router, ONT and PC kit | AC line-interactive UPS, 750VA/410W, AVR | 84 Wh | 4 IEC C13 sockets (needs UK leads) | 6 ms typical, 10 ms max | £84.82 at Amazon as of 21 Oct 2026, 10:37 BST · DetailsProduct prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.Out of stockCheck price → |
Our verdictOur verdictResearched APC's tower UPS has four IEC sockets and automatic voltage regulation, which corrects dips and surges without using the battery. The datasheet runtimes are about 8.5 minutes at half load, so it is the light-load runtime that matters for a router. It suits someone who already has IEC-to-plug leads and wants a slim tower. Home users with plug-in adapters will need those leads, which is a small extra step. Best for A small home-office desk: router, ONT and PC kit Good
Worth knowing
Who shouldn't buy it: Don't buy it if you want UK sockets built in; the BE650G2-UK has them and a similar battery. | |||||
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Before you buy
Start by reading the label on your router’s power adapter, not the router.
It gives the output voltage (often 12V, sometimes 9V or USB 5V) and a small diagram showing which part of the plug is positive. A mini DC UPS such as the APC CP12036LI replaces that adapter and feeds the router from its own cell, so voltage and plug size must match exactly: APC’s one-pager lists 12V output and three tip sizes, and an owner on APC’s forum found none fitted a BT Smart Hub 2. If your router is 9V, or your fibre box runs on a different voltage, a mini unit may not fit.
Size the battery against the watts you’ll actually draw.
A router usually pulls roughly 10 to 20W and a fibre terminal a few watts more, so a battery under about 30Wh gives an hour or two, while the 84Wh cells in the APC Back-UPS and Easy UPS towers give about two hours at that load. Trust runtime figures the maker publishes at a light load rather than the headline VA rating: CyberPower quotes 43 minutes at 90W for the UT1050EIG, a retailer quotes about two hours at 20W for the BE650G2-UK, and the CP1500EPFCLCD-UK only has half- and full-load figures. A bigger VA number does not mean more hours.
Choose between a mini DC unit and a mains UPS on what else you want covered.
A DC mini UPS is small, silent and wastes little, but it feeds one device at one voltage. A mains UPS keeps your existing adapters in use, so there is nothing to match, and its sockets can take the fibre box, a mesh node, a TV box or a laptop charger too. Check the socket type: the BE650G2-UK has UK three-pin sockets, while the BX750MI, BVX700LI and UT1050EIG use IEC C13 outlets and need kettle-style leads or an adapter. Line-interactive models add automatic voltage regulation, which rides out dips without touching the battery.
Know what wears out.
Most mains UPS boxes use a sealed lead-acid battery, and APC’s datasheets give two to five years of life; owners on APC’s forum report that beeping or a red light is the signal to replace it, and that a unit left to drain flat in a long cut can damage the cell. Check whether the battery is user-replaceable: APC says it is on the BE650G2-UK, CyberPower says it isn’t on the UT1050EIG. Lithium mini units like the CP12036LI avoid lead-acid, but their cells still age. Old UPS batteries are hazardous waste: use a council recycling centre or the retailer, never the bin.
Place and use it safely.
A UPS is for low-power electronics: never plug a heater, kettle, fridge or power tool into one, and never run it from an extension lead or adapter block, which Electrical Safety First and the fire services warn against overloading. Give it air, keep it off carpet and bedding, and keep its leads clear of water. Charge lithium kit on a hard surface with working smoke alarms (see our lithium battery fire-safety guide). If anyone at home relies on a medical device or careline alarm, treat the UPS as one layer only: join the Priority Services Register and ask the device supplier about its own backup.
We have not run down, timed or switched over any of these units ourselves, so nothing here is our own measurement. Every figure was checked on 12 October 2026 against the maker's product page or datasheet (APC via Schneider Electric, CyberPower's UK and EU pages), and against a second source such as a datasheet copy or a UK trade retailer's specification; we say which. Runtime figures are the maker's or a retailer's, stated as such. Owner-report themes, such as DC tips not fitting a router or lead-acid cells wearing out, are labelled 'owners report'. Amazon prices and stock come from Amazon's API on a schedule. Commissions never change a ranking. Read our full methodology →
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Common questions
Will my landline work in a power cut?
If your phone plugs into the router, or your provider has moved you to a digital line, no: it stops when the router loses power. Ofcom expects providers to have a way for customers to reach 999 for at least an hour in a cut, and to offer it free to at-risk customers who depend on their landline, such as a battery backup unit or a mobile handset. Ask your provider what they offer. A router UPS extends that window for everyone else in the home.
How long will a UPS keep my router running?
It depends on the battery and your load. A router and fibre box together draw about 15 to 25W. A 28Wh mini unit like the APC CP12036LI is quoted by APC at up to four hours for an average router but under an hour at its full 36W rating. An 84Wh tower such as the APC BE650G2-UK is quoted by a UK retailer at roughly two hours at 20W. CyberPower quotes 65 minutes at 60W for the UT1050EIG. Treat these as maker and retailer figures, not ours.
Can I use a power bank to run my router?
Sometimes. Routers that take USB-C power, or a 5V or 9V barrel plug, can run from a power bank with the right cable, and USB-C trigger cables can ask a power bank for 12V, but only if the bank supports 12V output, which many do not. It is fiddly, won't switch over by itself when the power drops, and a cable of the wrong voltage or polarity can damage the router. A UPS hands over automatically; a power bank is a manual fallback.
Does the fibre box (ONT) need power as well?
Yes. With full fibre, the small white terminal on the wall converts the light signal and needs mains like the router; with a cable or copper service the modem does the same job. If you back up the router but not the terminal, you'll have Wi-Fi with no internet. A mains UPS with several sockets covers both easily; a 12V mini unit only covers one device unless both run on the same voltage and the unit has two outputs.
Will broadband still work in a power cut if my router has backup?
Only if the network beyond your home still has power. If the cut is a tripped switch or a single property, yes. If a whole area is dark, a powered street cabinet or mobile mast may be down too (full fibre has no powered cabinet, but relies on the exchange), though exchanges and some mobile sites have their own backup. Little is published on how long each site lasts, so plan for a UPS to cover short, local cuts, and keep a charged mobile for anything bigger.
What's the difference between a mini DC UPS and a normal UPS?
A mini DC UPS sits between the router and its plug, storing power in a lithium cell and feeding the router directly at 12V or 9V, with no inverter. It is small, silent and efficient, but it must match your router's voltage and plug. A normal UPS is a mains box with sockets that takes your existing adapters, usually with a lead-acid battery and a few milliseconds' switch-over. It can run several devices and often smooths voltage dips, but it is bigger and the battery needs replacing every few years.
