👍 What we like
- ✓Prevents ZFS corruption and data loss during power outages
- ✓Triggers automatic clean shutdown via USB or NUT
- ✓Line-interactive models are sufficient for 99% of homelabs
- ✓Replaceable batteries extend unit lifespan significantly
👎 What to watch
- ✕Batteries degrade and require replacement every 3-5 years
- ✕Online UPS units are unnecessarily expensive and noisy for home use
- ✕Runtime is limited to minutes, not hours of backup power
🏆 Our picks
Affiliate links · same price for you
APC Back-UPS 700-900 VA
from ~$110
- ✓Auto-shutdown Synology/QNAP (USB)
- ✓Line-interactive, built-in AVR
- ✓Ultra-common reference
Eaton Ellipse / 5E
from ~$130
- ✓Very reliable, pro finish
- ✓Good software management
- ✓Easy battery replacement
CyberPower line-interactive
from ~$90
- ✓Often cheapest at equal VA
- ✓LCD screen on many models
- ✓USB for auto-shutdown (NUT)
📑 Contents ▾
You think about the NAS, the drives, the mini-PC… and forget about the UPS (Uninterruptible Power Supply). Yet, a simple power outage during a write operation can corrupt a ZFS volume, break a database, or interrupt a RAID resilver. A $100 UPS protects terabytes of data and triggers an automatic clean shutdown. It is the cheapest insurance for your infrastructure.
Line-interactive or online: which one to choose?
- Line-interactive (with AVR): regulates small voltage fluctuations and switches to battery power during an outage. More than enough for 99% of homelabs and NAS setups. This is what you want.
- Online (double conversion): power supply 100% via battery permanently, providing total isolation from the electrical grid. Reserved for critical use cases (professional servers, sensitive hardware). More expensive, noisier, and higher power consumption. Unnecessary for a home NAS.
Calculating the power you need
Two figures on a UPS: VA (apparent power) and W (real power). It is the watt value that matters for your hardware.
- Add up the real power consumption of what you plug in: a 4-bay NAS (~40-60 W) + a mini-PC (~15 W) + box/switch (~20 W) ≈ 100 W.
- Choose a UPS whose watt rating exceeds this total with a ~30% margin.
- A 700-900 VA / ~400-500 W model comfortably covers a NAS + mini-PC + networking gear, providing 5 to 15 minutes of autonomy — more than enough for a clean automatic shutdown.
The goal is NOT to last for hours, but to shut down your infrastructure cleanly before the battery dies.
The game-changing feature: automatic shutdown
A UPS that doesn’t trigger the shutdown of your machines is only half useful. Check for:
- USB port (or network) to communicate with your NAS/server.
- Synology/QNAP compatibility: these NAS devices natively support shutdown via USB UPS. APC and CyberPower are fully recognized.
- NUT (Network UPS Tools) on Linux/Proxmox/TrueNAS: an open standard that controls most APC, Eaton, and CyberPower UPS units. You can even configure a single UPS to trigger the shutdown of multiple machines on the network.
APC vs Eaton vs CyberPower
| Brand | Strengths | For whom |
|---|---|---|
| APC | Industry standard, maximum compatibility, huge community | The safe default choice |
| Eaton | Professional finish, reliability, replaceable batteries | Those who want durability |
| CyberPower | Best price per VA, LCD screen | Tight budgets |
Our selection
The cards above summarize the three sure bets. In practice:
- APC Back-UPS: you don’t need to ask questions, it works with everything.
- Eaton: if you want the best longevity and professional finish.
- CyberPower: the best price-to-performance ratio to get started.
Don’t forget the battery
UPS batteries degrade (3 to 5 years). Choose a model with a replaceable battery: you keep the unit and just change the battery, which is much cheaper than buying a complete new UPS.
Detailed specifications
| Model | Topology | Power | Runtime* | Outlets | Comms | Replaceable battery |
|---|---|---|---|---|---|---|
| APC Back-UPS 850 VA | Line-interactive (AVR) | 850 VA / 520 W | 5 – 15 min | 6 | USB — Synology/QNAP/NUT | Yes |
| Eaton Ellipse PRO 850 | Line-interactive (AVR) | 850 VA / 510 W | 5 – 15 min | 6 | USB | Yes |
| CyberPower 900 VA | Line-interactive (AVR) | 900 VA / 540 W | 6 – 16 min | 6 | USB — NUT | Yes |
*Indicative runtime for ~100 W load (NAS + mini-PC + network). The goal isn’t hours of uptime, but a clean automatic shutdown.
Go further
A good line-interactive UPS, properly sized, with automatic shutdown via USB or NUT: it’s $100 that saves you from losing years of data due to a 3-second power outage.