Best UPS for a Synology NAS in 2026: What I Actually Run

A UPS is the cheapest insurance you can buy for a NAS, and it’s the first thing I’d add to a setup that doesn’t have one. I lost power at my house a couple of years ago and my Synology shut itself down safely and came back on its own when the power returned, which is the entire reason this article exists. You’re spending around a hundred dollars to protect a device holding hundreds or thousands of dollars of hard drives and every photo you own.

Any UPS will keep a NAS powered for a few minutes. The part that actually matters is whether it can talk to the NAS over USB, because that’s what lets DSM shut the volume down cleanly before the battery dies. Every unit below does that, and I’ve run all of the APC models personally.

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Best UPS for a Synology NAS: My Quick Picks

• Best overall: CyberPower CP1500PFCLCD. Pure sine wave, 1500VA, and the only unit here I’d call future-proof. I own three.
• Best price to performance: APC BX1500M. Same capacity class, meaningfully cheaper, simulated sine wave.
• Best for most people: APC BE600M1. Enough for a NAS and a router, and the one I’d hand to someone who just wants this solved.
• Smallest sensible option: APC BE425M. NAS only, no headroom.
• For a DC-powered NAS: the UGREEN US3000, a 120W battery that sits inline on the power brick instead of on the floor.

Why a NAS Needs a UPS More Than Your Desktop Does

Every computer dislikes sudden power loss, but NAS devices are a special case because almost all of them run RAID. RAID writes data across multiple disks. If a write is in progress at the exact moment power cuts out, there’s a real chance you power the NAS back on and find a crashed volume waiting for you. The fix at that point is restoring the entire thing from a backup, assuming you have one, and if you don’t you get back whatever you happened to copy somewhere else.

That risk is the reason RAID can also rebuild a failed drive, so it isn’t a flaw so much as the trade-off that comes with redundancy. A UPS removes almost all of it: the NAS sees the switch to battery, waits however long you tell it to, and shuts down properly on its own. You still want a real backup running underneath all of this, and Hyper Backup is where I’d start if you don’t have one yet.

Pure Sine Wave vs. Simulated Sine Wave

This is the one specification worth understanding before you spend anything, and it’s the reason the CyberPower costs more than the APC units. Cheaper UPS devices output a stepped approximation of a sine wave when they’re running on battery, and most electronics tolerate that perfectly well. The complication is that modern power supplies with active power factor correction, which covers plenty of the PSUs in NAS units and home servers, can be fussy about it. In the worst case the power supply objects to the waveform and drops out during the transfer to battery, which defeats the entire point of owning the thing.

A pure sine wave unit produces the same clean waveform your wall outlet does, so nothing has to tolerate anything, and that’s why the CyberPower CP1500PFCLCD has PFC in its name. Being straight about it though: the APC units below have worked on every Synology I’ve plugged them into, and plenty of people run simulated sine wave units for years without a single problem. If the price gap is small, buy pure sine wave. If it isn’t, an APC is still an enormous upgrade over no UPS at all.

CyberPower CP1500PFCLCD: The Best UPS for a Synology NAS

The CP1500PFCLCD is 1500VA and 1000W with six battery backup outlets, a USB data port for the NAS, and an LCD that shows load and estimated runtime without you having to open anything. It’s the most expensive option here and it’s the one I’d buy again. I now own three of them, and every one replaced an APC unit that was working perfectly well at the time, which tells you how much I rate the waveform difference.

The catch is price and size. It’s a genuinely heavy mini-tower, and it costs noticeably more than the APC BX1500M for the same capacity class. If you’re only ever going to plug in a two-bay NAS, you’re paying for headroom you’ll never touch. Buy it if you have a home lab with a server or two alongside the NAS, or if you’d rather never think about power supply compatibility again.

APC BX1500M: Best Price to Performance

The APC BX1500M is 1500VA and 900W across ten outlets, five battery backed and five surge only, with automatic voltage regulation that corrects minor sags and swells without touching the battery. I ran one of these for years before upgrading, and when I lost power it gave me roughly 30 to 40 minutes with a NAS and a server attached. That is far more time than any shutdown sequence needs.

The only thing you give up against the CyberPower is the waveform, and for most home setups that’s a fair trade for the price difference. If the CP1500PFCLCD is a stretch, or the APC happens to be on sale, this is the one to get.

APC BE600M1: The One Most People Should Buy

The APC BE600M1 is 600VA and 330W across seven outlets, five battery backed and two surge only, with a 490 joule surge rating and keyhole slots so you can wall mount it. If you’re running a two or four bay Synology and a router, this is enough UPS and I’d stop here rather than spend more.

One point of confusion worth clearing up, because it trips people up on the spec sheet. APC markets this as having “1 USB charging port,” which is a USB-A port on the front for a phone. That is not the port you care about. There’s a separate USB-B data port for the NAS and the cable is in the box. You’ll also see that APC’s PowerChute software isn’t supported on this model, which sounds alarming and isn’t, because Synology doesn’t use PowerChute. DSM talks to the UPS directly over USB and the BE600M1 appears in Control Panel exactly like the larger units.

APC BE425M: The Smallest Option Worth Buying

At 425VA the BE425M is the smallest unit I’d put a NAS on, and it ships with the same USB cable and gets the same DSM support as everything else here. If the only thing on the battery side is the NAS itself, it genuinely does the job.

The catch is that it leaves you nowhere to go. Add a router later, or a second NAS, or a switch, and you’re shopping again. The gap to the BE600M1 is usually small enough that I’d just buy the 600VA and stop thinking about it. Get this one only if budget is the deciding factor.

What Capacity Do You Actually Need?

The number on the box is VA, and the more useful figure is usually the watt rating beside it. What matters in practice is simply how many things you’re plugging in, because everything on the UPS draws from the same battery.

• NAS only: 425VA is genuinely enough. You need a few minutes, not a few hours.
• NAS plus a router or modem: 600VA. This is the setup most people should buy, and keeping the network alive is what makes the next section possible.
• NAS plus a server, switch, and access point: 1500VA, and this is where the larger units earn their price.

Runtime isn’t really the goal. You’re buying enough time for the NAS to notice the outage, ride out a brief flicker, and shut down in an orderly way. Anything past about ten minutes is comfort rather than necessity. One detail people get wrong constantly: most UPS devices have two banks of outlets and only one is battery backed, with the other being surge protection only. Plug your NAS into the battery side or none of this works.

Will Your Existing UPS Work With a Synology NAS?

If you already own a UPS you probably don’t need to buy anything. The requirement for any UPS for Synology NAS use is that it exposes a USB data port and speaks the standard USB HID power protocol. The overwhelming majority of consumer units do, without a driver or any extra software.

Synology publishes an official UPS compatibility list if you want to confirm a specific model. Plenty of units that aren’t on it work perfectly well, because the list reflects what Synology has tested rather than what functions. If yours isn’t listed, plug it in and see whether DSM recognises it before assuming anything. DSM also supports SNMP UPS devices for rack units already monitored over the network, but for almost everyone reading this, USB is the right answer.

How to Set Up a UPS on a Synology NAS

The Synology UPS settings live in Control Panel and the configuration takes about two minutes. It’s identical on every model above.

1. Power down the NAS and plug it into a battery plus surge outlet, not a surge-only one.
2. Connect the USB cable from the UPS data port to a USB port on the NAS, then power the NAS back on.
3. Open Control Panel, go to Hardware & Power, then the UPS tab.
4. Tick Enable UPS support and set the UPS type to USB UPS.
5. Choose how long the NAS waits before entering standby, either a fixed time or when the UPS battery is low.
6. Click Device Information to confirm the NAS and UPS are actually talking to each other.

There’s one more setting people skip, and it’s the one that makes this automatic rather than half automatic. In Control Panel under Hardware & Power, open the General tab and enable Restart automatically when power supply issue is fixed. Without it the NAS shuts down safely and then sits there waiting for you to press the button. That is not much use if the outage happens while you’re away.

Shutting Down Other Devices With the Network UPS Server

Protecting the NAS is the important part, but a server or two on the same UPS needs to shut down as well. Synology handles this with a feature called the network UPS server. Turning it on makes the NAS act as a NUT server. Other machines then run a NUT client, watch the NAS for battery status, and power themselves off once the UPS has been on battery for however long you specify. Mine is set to shut down after five minutes on battery, comfortably inside the runtime I have available.

• Every client has to be configured individually, because there’s no discovery and nothing happens automatically.
• You need to add each client’s IP address on the NAS side so the two can communicate.
• Your network gear has to be on the UPS too, because if the switch dies the moment power is lost, the clients can’t see the NAS and nothing shuts down.
• Only include devices physically plugged into that UPS. Telling a machine on a different circuit to shut down is not useful.

Because you’re now powering the NAS, the switch, and whatever else, this is the scenario where the CyberPower or the BX1500M stop being overkill. There’s a detailed Reddit write-up covering NUT client setup on Linux, Windows, and macOS, and I’ve written the reverse arrangement where TrueNAS acts as the NUT server if that fits your setup better.

Synology NAS UPS Devices Compared

Which UPS Should You Buy?

• You have a NAS and a router and want this solved: the APC BE600M1. Cheap, small, and it does the one job that matters.
• You have a home lab and want the best power delivery: the CyberPower CP1500PFCLCD. This is what I run.
• You want 1500VA without the pure sine wave premium: the APC BX1500M.
• Budget is the deciding factor and it’s the NAS alone: the APC BE425M.
• Your NAS uses a DC power brick: the UGREEN US3000.
• You already own a UPS with a USB port: keep it. Plug it in, enable UPS support in DSM, and spend the money on better drives instead.

Conclusion

Buy the CyberPower CP1500PFCLCD if the budget allows, because pure sine wave output removes the one genuine compatibility question around UPS devices and modern power supplies, and it has the capacity to cover whatever you add later. If that’s more than you want to spend, the APC BE600M1 is the pick I’d hand to most people. It fits a NAS and a router, and it does the one thing that actually matters, which is telling DSM to shut down before the battery runs out.

Whichever you pick, plug it into the battery side, turn on the automatic restart setting, and then confirm it works by pulling the plug on the UPS and watching what your NAS does. Finding out the configuration was wrong during a real outage is a bad way to learn it. If you’re still setting the rest of the NAS up, my Synology setup guide covers everything else worth configuring on day one.