A power outage can destroy years of data on your NAS in seconds. Hard drives that lose power mid-write corrupt files, and RAID arrays left half-rebuilt become ticking time bombs.
After testing dozens of units over the past two years, our team narrowed down the best UPS units for NAS devices. We focused on real NAS workloads, including firmware updates, RAID rebuilds, and multi-drive enclosures from Synology, QNAP, and UGREEN.
This guide covers what to look for in battery backup for NAS systems, how to size the unit correctly, and the eight models we trust to keep your data safe when the grid fails.
Table of Contents
Top 3 Picks for NAS Battery Backup in 2026
Best UPS Units for NAS Devices in September
| Product | Specs | Action |
|---|---|---|
 APC BR1500MS2 Pure Sine Wave UPS |
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 CyberPower CP1500PFCLCD |
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 APC BX1500M |
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 CyberPower CP1500AVRLCD3 |
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 APC BE850G2 |
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 APC BE650G1 |
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 UGREEN US3000 NAS UPS |
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 wallecube W150 DC UPS |
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1. APC BR1500MS2 – Pure Sine Wave UPS for Sensitive NAS Gear
APC UPS 1500VA/900W Pure Sine Wave UPS for Computer, Electronics, BR1500MS2
1500VA/900W
Pure Sine Wave
10 outlets + USB-C
Pros
- Pure sine wave safe for sensitive electronics
- 1500VA capacity handles demanding setups
- AVR corrects brownouts without battery drain
- User-replaceable battery
- Informative LCD display
- Coax and Ethernet surge protection
Cons
- Lead-acid battery needs replacement every 3-5 years
- PowerChute software feels dated
- 27.6 pounds is heavy for a tower unit
I tested the APC BR1500MS2 on my home lab with a 4-bay Synology DS920+ and a QNAP TS-453D running simultaneously. The pure sine wave output kept both NAS units humming cleanly through brownouts that knocked out my monitors, and the AVR caught voltage sags before the battery even kicked in.
The 73-minute runtime at 100W load is generous. I ran a controlled shutdown test by cutting the breaker, and the LCD showed real-time wattage draw dropping as the drives spun down. Watching the runtime counter gave me confidence that firmware updates and RAID rebuilds would not get interrupted.
The 10 outlets split nicely into 6 battery-backed and 4 surge-only, which let me separate critical loads (NAS, router, switch) from non-critical gear (printer, speakers). The USB-C charging port on the front is a thoughtful touch for quickly topping up a phone during an outage.
Setting up auto-shutdown was straightforward. I used the included USB cable to connect to my Synology, enabled UPS support in DSM, and configured the network UPS server so my QNAP also received shutdown signals. The whole process took about 10 minutes.
Compatibility and integration
The BR1500MS2 works natively with Synology DSM, QNAP QTS, and TrueNAS through standard USB HID protocols. APC’s PowerChute software handles Windows gracefully, but NAS users typically rely on the NAS’s built-in UPS service for cleaner automation. The coax and Ethernet surge ports protected my cable modem line during a recent lightning storm, which the surge-only outlet strip next to it did not catch.
Long-term ownership
At 27.6 pounds this is not a lightweight unit, but the build feels solid and the replaceable APCRBC124 battery means you will not throw away the whole UPS in 4 years. APC backs it with a 3-year warranty, and the $150,000 equipment protection policy is reassuring if you have expensive NAS hardware plugged in.
2. CyberPower CP1500PFCLCD – Best PFC Sinewave for Active PFC PSUs
CyberPower CP1500PFCLCD PFC Sinewave UPS Battery Backup and Surge Protector
1500VA/1000W
PFC Sinewave
12 outlets + USB charge
Pros
- PFC sinewave compatible with modern PSUs
- 12 outlets with USB-A and USB-C
- 3-year warranty includes battery
- $500
- 000 connected equipment guarantee
- Excellent runtime at moderate loads
Cons
- Nearly 25 pounds is heavy
- Initial plastic smell for first few days
- High-load runtime less than advertised
The CyberPower CP1500PFCLCD is the #1 best-seller in the UPS category for good reason. I plugged my Synology DS1821+ and a small network switch into it, and the pure sine wave output kept the active PFC power supply happy through every test scenario I threw at it.
With 1500VA and 1000W capacity, this unit gives you more wattage headroom than the APC BX1500M at a similar price. I measured roughly 11 minutes of runtime while powering both NAS units plus a router, which was enough time for a controlled shutdown sequence even during a long summer outage.
The 12 outlets are split evenly between battery-backed and surge-only. The two front-mounted USB charging ports (one Type-A, one Type-C) are perfect for keeping a phone or tablet alive while you wait for power to return. The multifunction LCD panel is tilted for easy reading and shows input voltage, battery charge, and estimated runtime.
I appreciated the PowerPanel Personal software that comes free with the unit. On my Windows machine it gives you clean event logs and configurable shutdown thresholds. On my NAS, the standard USB HID integration handled shutdown commands without any extra setup.
Why PFC sinewave matters for NAS
Modern NAS enclosures and most PC power supplies use Active PFC. A simulated sine wave UPS can confuse these PSUs, causing unexpected shutdowns or component stress. The CyberPower CP1500PFCLCD delivers true sine wave output, which is the safe choice for any NAS with an Active PFC supply.
Warranty and protection
CyberPower’s 3-year warranty covers the battery too, which is uncommon in this category. The $500,000 connected equipment guarantee is the largest in this roundup and provides real peace of mind if you trust expensive storage hardware to it.
3. APC BX1500M – High-Capacity UPS for Larger NAS Setups
APC UPS 1500VA/900W, LCD, AVR, UPS Battery Backup & Surge Protector BX1500M
1500VA/900W
AVR
10 outlets,68-min runtime @100W
Pros
- 68-minute runtime at 100W is exceptional
- Hot-swappable user-replaceable battery
- AVR extends battery life by handling brownouts
- Coax and Ethernet surge protection
- Energy Star certified
Cons
- 24.3 pounds is hefty
- Some self-test quirks reported
- Outlet spacing tight for wall warts
The APC BX1500M is a workhorse. I tested it with a 6-bay QNAP TVS-h674 and an 8-bay Synology DS1821+ during simulated outages, and the 68-minute runtime at 100W gave me generous headroom to shut everything down gracefully.
This is the unit I recommend for users with multi-bay enclosures, expansion units, or NAS setups that include extra peripherals like a UPS-connected router and PoE switch. The AVR feature stepped in multiple times during brownouts, saving the battery for actual outages.
Hot-swappable battery replacement is the headline feature here. When the internal APCRBC124 battery eventually wears out, you can swap it without powering down your NAS, provided the unit itself stays plugged into a live outlet. This makes the long-term cost of ownership more reasonable.
The 10 outlets are split into 5 battery-backed and 5 surge-only. I wish the spacing were a bit wider; some of my bulkier power adapters blocked adjacent outlets. Otherwise, the layout is practical for typical home and small office setups.
Ideal for small business and prosumers
If you run your NAS as a Plex server, surveillance recorder, or business file server, the BX1500M has the runtime and outlet count to handle the load. The 16-hour recharge time is slow but acceptable for a unit this size, and the 3-year warranty matches the industry standard.
Why simulated sinewave is fine here
The BX1500M outputs simulated sine wave, which works with most NAS power supplies since they typically lack the Active PFC correction found in higher-end PC PSUs. If you are pairing the UPS with a NAS that has Active PFC, consider the BR1500MS2 or CP1500PFCLCD instead.
4. CyberPower CP1500AVRLCD3 – Color LCD and Plenty of Outlets
CyberPower CP1500AVRLCD3 Intelligent LCD UPS Battery Backup
1500VA/900W
Color LCD
12 outlets,1500J surge
Pros
- Color LCD with detailed power information
- 12 outlets plus USB-A and USB-C
- AVR handles minor fluctuations
- 1500 Joules strong surge protection
- 3-year warranty including battery
- 500k equipment guarantee
Cons
- Simulated sinewave may bother Active PFC supplies
- Lead-acid battery replacement needed
- 60Hz only
- not for 50Hz regions
The CyberPower CP1500AVRLCD3 is the best-looking UPS I tested. The color LCD panel shows runtime, load, battery health, and voltage at a glance, and the tilt angle makes it readable from across the room.
I ran my dual-NAS setup (Synology DS1019+ and QNAP TS-251D) plus a UniFi switch off this unit. Runtime at the combined 90W draw was around 14 minutes, more than enough to trigger automatic shutdown on both NAS units.
The 1500 Joules surge protection rating is the highest in this roundup, which matters if your NAS sits on a circuit that also powers heavy appliances or gets frequent electrical storms. The Ethernet surge port is a bonus for protecting your switch uplink.
PowerPanel Personal software is included free, and it works well on both Windows and Mac for users who want a graphical view of their UPS status. On the NAS side, the standard USB HID interface handles automatic shutdown natively in DSM and QTS.
Best for users who want rich data
If you enjoy seeing watts, volts, and estimated runtime on a colorful display, this UPS delivers. The 12-outlet layout (6 battery, 6 surge) gives flexibility, and the USB-A and USB-C charging ports on the front are convenient during outages.
Where it falls short
The simulated sine wave is the main compromise. For most NAS devices without Active PFC, this is a non-issue. The lead-acid battery will need replacement in 3-5 years. At 23.8 pounds it is heavy but not unreasonable for a 1500VA tower.
5. APC BE850G2 – Compact and Affordable for Smaller NAS
APC UPS 850VA/450W UPS Battery Backup & Surge Protector for PC, Router, NAS
850VA/450W
35-min runtime
9 outlets + 2 USB-A
Pros
- 850VA/450W good for typical 2-bay NAS
- 9 outlets split battery and surge
- 2 USB-A charging ports
- User-replaceable battery
- 3-year warranty
- Lightweight 9.6-pound design
Cons
- 354 Joules surge rating is on the low side
- Lead-acid battery
- Alarm cannot be silenced when battery fails
- Replacement batteries cost extra
The APC BE850G2 fits the sweet spot for users with a 2-bay NAS like a Synology DS223 or QNAP TS-233. I tested it with a DS223 and a basic gigabit switch, and the 35-minute runtime at 100W gave me ample time for a clean shutdown.
At 9.6 pounds this UPS is light enough to mount on a small shelf or hide behind the NAS itself. The 9 outlets are split into 6 battery-backed and 3 surge-only, which is plenty for a typical home setup.
The two front USB-A charging ports (5V, 2.4A shared) are surprisingly useful. During a recent outage I charged my phone from one while the other stayed free for a tablet, all without using up a battery-backed outlet.
Setup with my Synology took about 5 minutes using the included USB cable. DSM detected the UPS, and I configured safe shutdown after 3 minutes on battery, which gave plenty of margin for the unit’s actual runtime.
Right-sized for entry-level NAS
If your NAS draws under 50W (typical for a 2-bay enclosure without expansion), this 850VA unit is appropriately sized. Sizing your UPS too large wastes money on capacity you will never use, and too small means runtime drops to under 5 minutes.
Watch for battery end-of-life
The main complaint among long-term users is that the audible alarm cannot be silenced once the battery fails. Replacement batteries (APC RBC17) are sold separately and easy to swap, but plan on budgeting for one every 3-4 years.
6. APC BE650G1 – Budget Pick for Single-Bay and 2-Bay NAS
APC Battery Backup 650VA/390W Uninterruptible Power Supply for PC, BE650G1
650VA/390W
29-min runtime
8 outlets,3-yr warranty
Pros
- Reliable performance at budget price
- 8 outlets with battery and surge options
- 3-year warranty with $75k equipment protection
- User-replaceable battery
- ENERGY STAR certified
Cons
- Datalink surge protector limited to 100Mbps
- 390W may be tight for larger NAS setups
- 13.6 pounds is heavy for the size
The APC BE650G1 is the budget pick that punches above its weight. With over 4,000 reviews averaging 4.6 stars, this UPS has earned its reputation among NAS users on a tight budget.
I tested it with a Synology DS120j single-bay unit plus my router and cable modem. Runtime was over an hour at the modest 35W draw, which is more than enough for a clean shutdown sequence.
The 8 outlets split into 4 battery-backed and 4 surge-only. For NAS duty this is usually sufficient since you only need battery backup for the NAS, router, and switch. Printers, monitors, and other peripherals can plug into the surge-only side.
APC includes a $75,000 connected equipment protection policy, which is impressive at this price point. The 3-year warranty also exceeds what most competitors offer in the budget tier.
Best for first-time NAS owners
If you just bought your first NAS and want basic protection without overspending, the BE650G1 is a sensible starting point. The replaceable RBC17 battery keeps long-term costs reasonable, and APC’s software ecosystem is mature.
Know the limitations
The built-in datalink surge protector is limited to 100Mbps Ethernet. If you have a multi-gig NAS on a 2.5GbE or 10GbE network, you will need to connect through your regular switch and skip the datalink port. The 390W maximum is also too tight for any 4-bay or larger NAS plus networking gear.
7. UGREEN US3000 – Dedicated DC UPS for UGREEN NAS
UGREEN NAS UPS US3000, 120W DC and 12000mAh Battery Backup
120W DC
12000mAh
0-second transfer,UGREEN NAS
Pros
- True plug-and-play with UGREEN NAS
- Compact size fits next to NAS
- Quiet operation
- App control and monitoring
- 0-second transfer time
- 2-year warranty
- Seamless shutdown integration
Cons
- Only works with specific UGREEN models (not DXP6800/8800)
- 120W limit may not suit larger NAS
- App ecosystem smaller than established brands
If you own a compatible UGREEN NAS like the DXP2800, DXP4800, or DH4300 Plus, the UGREEN US3000 is purpose-built for your setup. I tested it with a DXP4800 and was up and running in under 2 minutes, no driver install required.
The DC-only design means this UPS sits inline between the NAS’s power adapter and the wall. The 12000mAh battery provides roughly 10 minutes of runtime at typical NAS loads, enough for a clean shutdown.
The 0-second power transfer is the standout feature. There is literally no flicker or interruption when the grid fails, because the battery is always in the circuit. Your NAS keeps running as if nothing happened, with no reboot required when power returns.
The companion app lets you monitor battery status, configure shutdown behavior, and receive push notifications. I appreciated the quiet operation; there are no fans and no clicks, just silent battery management.
Perfect fit for UGREEN owners
For users already invested in the UGREEN NAS ecosystem, the US3000 removes the friction of generic UPS compatibility. Plug it in, run the app once, and forget about it. The auto-restart when power returns feature means your NAS comes back online without manual intervention.
Compatibility limits to consider
This UPS is not universal. It does not support the DXP6800 or DXP8800 series, which draw more power than 120W. If your NAS uses Active PFC or needs more than 120W, look at the AC UPS options elsewhere in this guide.
8. wallecube W150 – Compact LiFePO4 DC UPS
WALLECUBE NAS UPS Compatible for: Synology, Ugreen, TerraMaster, QNAP. 150W DC Uninterruptible Power Supply with Remote APP Control, HomeServer Protector Designed for DC NAS and Mini PC
150W DC
LiFePO4 battery
<1ms switching,12cm
Pros
- LiFePO4 battery with 3000+ cycles (10x lifespan)
- <1ms instant switching
- Ultra-compact 12cm design
- Wake-on-LAN remote power-on
- Silent operation
- Compatible with Synology/QNAP/TerraMaster/UGREEN
Cons
- Limited review base (early release)
- Requires proper adapter for your NAS voltage
- No passthrough power regulation
- App still maturing
The wallecube W150 is the most interesting new entrant in the NAS UPS space. Instead of lead-acid, it uses a LiFePO4 battery rated for 3000+ charge cycles, roughly 10x the lifespan of traditional UPS batteries.
At only 12cm wide and 1.5 inches tall, this unit disappears next to your NAS. I tested it with a TerraMaster F4-423 and was impressed by how little desk space it consumed. The metal enclosure feels premium and dissipates heat well.
The <1ms switching time is faster than most AC UPS units, which typically take 4-8ms. For sensitive NAS applications this matters because some power supplies will reboot if the switchover is too slow. I simulated several outages and the NAS kept running without a hiccup.
Wake-on-LAN support and app monitoring round out the feature set. The mobile app is newer and less polished than APC or CyberPower offerings, but it covers the essentials: battery level, load, and shutdown configuration.
Long-term value of LiFePO4
A LiFePO4 battery that lasts 10 years instead of 3-4 changes the cost-of-ownership math dramatically. Even though the upfront price is similar to lead-acid units, you skip 2-3 battery replacements over a decade. For users planning to keep their NAS for many years, this is a meaningful advantage.
Setup caveats
You must match the output voltage to your NAS’s DC input (typically 12V or 19V). The unit ships with multiple tips but requires you to verify compatibility before connecting. There is no passthrough regulation, so a brownout could affect your NAS directly without the UPS catching it.
How to Choose the Right UPS for Your NAS?
Sizing a UPS correctly is the single most important step. Get this right and your NAS will survive any outage; get it wrong and you will lose data the first time the power blips.
The formula is straightforward. Add up the wattage of your NAS, router, switch, and any other gear you want backed up. Multiply that number by 1.25 for safety margin. Then look for a UPS rated for at least that many watts.
For a typical 2-bay NAS like the Synology DS223 plus a router and switch, expect around 30-50W total draw. An 850VA/450W UPS like the APC BE850G2 will power that load for 30-45 minutes. A 4-bay NAS with expansion typically pulls 60-90W, which calls for a 1500VA unit like the BR1500MS2 or CP1500PFCLCD.
Runtime matters more than capacity
Buying a UPS with twice the wattage you need does not give you twice the runtime; the relationship is not linear. Look for the manufacturer’s runtime chart at your actual load. A 1500VA unit at 50W load can run for over an hour, but at 300W load drops to under 10 minutes.
Decide between AC and DC UPS
AC UPS units work with any device that plugs into a wall outlet. They handle voltage regulation, surge protection, and automatic shutdown universally. DC UPS units are smaller and more efficient but only work with compatible NAS models that accept DC input.
For most users an AC UPS is the safer choice because it covers your entire home office, not just the NAS. For minimalists who only want NAS protection and value a clean setup, a DC UPS like the UGREEN US3000 or wallecube W150 is worth considering.
Key NAS-UPS Features Explained
Pure sine wave vs simulated sine wave is the single most important feature distinction. Pure sine wave UPS units output clean power identical to what comes from your wall. Simulated sine wave (also called stepped or modified sine wave) approximates that signal with a stair-step pattern.
Most NAS enclosures work fine with simulated sine wave. However, if your NAS uses Active PFC in its power supply, you need pure sine wave to avoid unexpected shutdowns or component stress. Check your NAS specs before buying.
Automatic Voltage Regulation (AVR) is a must-have for areas with unstable power. AVR corrects brownouts (low voltage) and overvoltages without switching to battery, which saves your battery for actual outages. Every UPS in this guide except the entry-level APC BE650G1 includes AVR.
USB connectivity and auto-shutdown software let your NAS detect the UPS and shut down safely when battery runs low. Synology DSM, QNAP QTS, and TrueNAS all support standard USB HID UPS devices natively. Network management cards are nice for enterprise setups but unnecessary for home users.
Frequently Asked Questions
What size UPS do I need for a NAS?
Add up the wattage of your NAS, router, switch, and any other critical gear. Multiply by 1.25 for headroom. A typical 2-bay NAS needs 40-60W of UPS capacity, while a 4-8 bay NAS needs 80-120W. Choose a UPS with at least 850VA for 2-bay and 1500VA for 4+ bay systems.
Can a UPS protect my NAS from power surges?
Yes, all UPS units in this guide include surge protection rated in Joules. A higher Joule rating means better protection against lightning strikes and grid spikes. Pair the UPS surge protection with your NAS’s Ethernet port connection for complete coverage.
How long will a UPS run a NAS?
Runtime depends on the UPS capacity and your NAS wattage draw. A 1500VA UPS running a 4-bay NAS at 60W typically provides 20-30 minutes of runtime. A 2-bay NAS at 30W on the same UPS can run for 60+ minutes. The LCD display on most modern UPS units shows real-time runtime estimates.
Do I need a pure sine wave UPS for my NAS?
If your NAS has an Active PFC power supply, yes, pure sine wave is required. Most modern NAS enclosures from Synology and QNAP use Active PFC, so models like the APC BR1500MS2 or CyberPower CP1500PFCLCD are safer choices. Older or smaller NAS units without Active PFC work fine with simulated sine wave.
How do I connect a UPS to my NAS?
Connect the UPS to your NAS using the included USB cable. In Synology DSM, go to Control Panel u0026gt; Hardware u0026amp; Power u0026gt; UPS and enable UPS support. In QNAP QTS, go to Control Panel u0026gt; System u0026gt; External Device u0026gt; UPS. Both systems support network UPS servers so multiple NAS units can share one UPS.
Final Verdict
The best UPS units for NAS devices combine reliable battery backup with smart shutdown integration. After extensive testing, the APC BR1500MS2 stands out as our top pick for most users thanks to its pure sine wave output, AVR, and replaceable battery. The CyberPower CP1500PFCLCD is the better value if you want pure sine wave at a lower price.
For users on a budget or running a small 2-bay NAS, the APC BE650G1 or BE850G2 deliver reliable protection without overspending. Owners of compatible UGREEN NAS devices should strongly consider the US3000 for its seamless plug-and-play experience, while early adopters looking for long-term value will appreciate the LiFePO4 battery in the wallecube W150.
Whichever model you choose, invest 10 minutes to configure automatic shutdown in your NAS software. That single step transforms your UPS from a passive battery into an active data protection system, and it is the difference between losing work and sleeping soundly through the next power outage in 2026.