APC CP12036LI review
APC Back-UPS Connect CP12036LI 12V Mini UPS
By Tom Calder
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
- Skip it if
- Your router or fibre box runs on 9V or 5V, or you want to cover several devices
as of 2 Nov 2026, 16:07 GMT · 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.We earn a commission if you buy through the retailer links on this page. It doesn't change our verdict. How we make money →
Researched, not used. We haven't used this product. This review is built from the maker's specifications, owner reports and our own sizing.
What we like
- APC states the battery size (27.75 Wh) and runtime figures, so you can size it
- Three DC tips included for common router plugs
- Lithium cell is light and compact
Worth knowing
- 12V only: no 9V or 5V router can use it
- Capacity is modest, so a 15W router lasts well under two hours
- One owner on APC's forum found the supplied tips did not fit a BT Smart Hub 2, so check your plug size first
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Our review
The APC Back-UPS Connect CP12036LI is a small lithium battery that sits between a 12V router's power adaptor and the router, and keeps it running when the mains fails. APC quotes up to four hours for an average router. It is the simplest way to keep home broadband and Wi-Fi calling alive through a power cut, provided your router runs on 12V.
What it is
Schneider Electric, APC's parent, lists it as a 12V DC, 36W lithium-ion mini network UPS for routers, IP cameras and similar kit, with two extra pairs of DC tips in the box to fit common router plugs. APC gives the battery as 27.75Wh. Its runtime claims are four hours at most for a typical router, falling to 45 minutes when the load is 80% of the 36W rating. Because it passes DC straight through, there is no switchover gap: the router never notices the cut. A distributor datasheet gives a recharge of around nine hours and a 2W standby draw; APC does not confirm those figures on its page.
Check your router first
The unit only works with equipment that runs on 12V DC through a barrel plug. Many UK routers and fibre terminals do, but some use 9V or 5V, and some use a non-standard plug. Read the label on your router's adaptor before buying, and check the plug size against the three tip sizes supplied. Owners on APC's own forum have found some BT hubs do not fit the supplied tips, so if yours is a BT Smart Hub, confirm the connector before you order.
How long it really lasts
Four hours assumes a router drawing around 7W. A fibre terminal plus a bigger Wi-Fi 6 router can draw 15W or more, which halves the time, by our arithmetic from APC's 27.75Wh figure. For most households that still covers the typical cut, which is restored within an hour or two, and it keeps Wi-Fi calling and smart-home hubs up while the mobile mast's own battery lasts. Our power cut preparation guide explains why keeping the router alive matters more than it used to.
How it compares
On the router battery backup page the APC BE650G2-UK is a mains UPS with UK sockets that takes your existing adaptors, covers a router and a fibre box together, and suits anything that is not 12V. The APC BX750MI and CyberPower units scale that up to a home-office desk. The CP12036LI is the smallest, cheapest and tidiest of the set, and the right one when a single 12V router is all you need to keep up.
Our verdict
Buy it if your router or fibre terminal runs on 12V through a barrel plug, you want a neat box with no fan and no sockets, and a few hours of broadband through a cut is the whole job. Skip it if your router is 9V or 5V, if you need to cover several devices, or if you want more than a few hours: a mains UPS or a small power station does those jobs.
A researched review, built from the maker's specs, manual and UK listings; facts checked 2 Nov 2026. Sources: Schneider Electric (APC): Back-UPS Connect CP12036LI product page; CEF: Schneider CP12036LI datasheet (PDF).
Who shouldn't buy this
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.
Key specs
| Type | 12V DC mini UPS, lithium-ion |
| Capacity | 27.75 Wh |
| Outputs | 12V DC, 36W max, 3 barrel tips |
| Switchover | Instant (DC pass-through) |
This is a Researched review: we haven't used this product. We check every specification against at least two independent sources, re-check the UK price on a schedule where we can track it automatically, and say plainly who it isn't for. Commissions never change a rating.
If this isn’t the one
Best for Router, fibre box and a PC or TV on one UK-plug unit
as of 2 Nov 2026, 16:07 GMT · 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.
Best for A whole desk of kit, including a mesh system and a NAS
as of 2 Nov 2026, 16:07 GMT · 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.
Best for A small home-office desk: router, ONT and PC kit
as of 2 Nov 2026, 16:07 GMT · 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.Questions
How long will the APC CP12036LI keep a router running?
APC's figures are four hours at most for a typical router, and 45 minutes at 80% of the 36W rating. A router and fibre terminal drawing 15W together get about two hours from its 27.75Wh battery.
Will the CP12036LI work with my router?
Only if the router runs on 12V DC through a barrel plug. Check the label on your router's power adaptor and the plug size against the three tip sizes APC supplies.
Is there a switchover delay when the power fails?
No. The unit passes 12V DC through from the adaptor and takes over from its own battery without a gap, so the router stays connected.
Does it work with a BT Smart Hub?
Some owners on APC's forum report the supplied tips do not fit a BT Smart Hub 2. Check the connector and voltage on your hub's adaptor before buying.
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