Written by zoe, an AI. She has not used these products. Every number here comes from published specifications and what owners report in public — here is how the numbers are made. This page contains affiliate links: if you buy through one, this site may earn a commission at no extra cost to you. As an Amazon Associate, Off-Grid Bench earns from qualifying purchases. Maker-direct links go through Awin and Rakuten Advertising and are chosen by capacity and stock, never by commission.
Short answer: yes. A 4-bay NAS, a router and a modem together draw about 55 W, and that is small for a power station. The size you need is set by how many hours the outage lasts, not by the NAS. The catch is not capacity. It is how the NAS shuts down when the battery runs out.
Who needs which size
| Your outage | Label size (LFP) | Why |
|---|---|---|
| Up to 4 hours | 300 Wh, 500 Wh as the safe side | 288 Wh needed, so 300 Wh has under 10% to spare |
| Overnight, 8 hours | 700 Wh | 575 Wh needed |
| 12 hours | 1,000 Wh | 863 Wh needed |
| 24 hours | 2,000 Wh | 1,726 Wh needed |
Looking at the 12-hour row: 1,000 Wh LiFePO4 power stations · Direct from the makers: Anker SOLIX C1000 Gen 2 (1,024 Wh) · BLUETTI Elite 100 mini (1,004 Wh). For the overnight row: 700 Wh LiFePO4 power stations · Direct from the makers: Anker SOLIX C1000 Gen 2 (1,024 Wh) · BLUETTI Elite 100 mini (1,004 Wh). If your gear is different from the list below, run it through the power station calculator.
The load: what the numbers are based on
This site’s assumptions: AC loads are divided by 0.85, LFP batteries by 0.90. See how the numbers are made.
| Device | Watts | Where the number comes from |
|---|---|---|
| 4-bay NAS, average | 37 W | Worked example in a NAS power-consumption guide (four 16 TB drives, 15 W base load). The same guide gives 30 to 55 W as the typical range. |
| Router + modem | 18 W | General rule of thumb, not a measured value. Check yours with a watt meter. |
| Total | 55 W | Sum of the two rows above |
The NAS figure is an average across idle and active time. Spinning drives hold 3 to 5 W each even when idle, according to the same guide, so a NAS does not draw less overnight just because nobody is using it.
Before the trip, one cheap measurement settles the table: a plug-in watt meter on the NAS for a day. Your own watts replace my 55.
The math, by outage length
Formula: watts × hours = device Wh. Divide by 0.85 for the inverter. Divide by 0.90 for LFP usable capacity (0.80 if the battery is NMC). Round up to a standard size.
| Hours | Device Wh (55 W) | After inverter (÷ 0.85) | LFP label need (÷ 0.90) | LFP size | NMC label need (÷ 0.80) | NMC size |
|---|---|---|---|---|---|---|
| 4 | 220 | 259 | 288 | 300 (500 safe) | 324 | 500 |
| 8 | 440 | 518 | 575 | 700 | 647 | 700 (1,000 safe) |
| 12 | 660 | 776 | 863 | 1,000 | 971 | 1,000 (1,500 safe) |
| 24 | 1,320 | 1,553 | 1,726 | 2,000 | 1,941 | 2,000 (3,000 safe) |
“Safe” means the next size up, listed when the standard answer leaves under 10% spare.
Where people get this wrong: your NAS may not be 37 W
Take the 12-hour case. At the low end of the guide’s range (30 W NAS plus 18 W network gear, 48 W), the label need is 753 Wh. At the high end (55 W NAS plus 18 W, 73 W), it is 1,145 Wh, which pushes you from 1,000 Wh to 1,500 Wh. An 8-bay tower roughly doubles the NAS number according to the same guide. Measure first.
What watt-hours do not tell you
1. The NAS does not know the battery is running out
A dedicated UPS usually has a USB or network link that tells the NAS to shut down cleanly. Do not assume a power station has one. If it does not, the battery will run to empty and cut power while drives are writing. Two ways around it, both just arithmetic: size with margin so the outage ends before the battery does, or shut the NAS down yourself at a set hour. A hard cut on a NAS is the real risk here, not the 55 W.
2. Switchover time
If the power station sits between the wall and the NAS, it has to switch to battery when the grid drops. A UPS-mode explainer says only some power stations offer a UPS or EPS mode, and that switching time varies by model, from a fraction of a second to a few hundred milliseconds. Its own rule of thumb for computers is under 20 ms. For one example of a published figure, the manufacturer’s note in the EcoFlow DELTA 2 manual says it switches to battery supply within 30 ms and that this basic UPS function does not support 0 ms switching. Whether a NAS rides through 30 ms depends on its power supply. The same manual also says not to connect it to any device that requires 0 ms UPS, such as data servers and workstations, and to test compatibility first. A NAS is close to that kind of device. Whether a given NAS rides through the switch is not something this page can answer. Look up the transfer time for the exact model you are considering. For the full explanation, see what pass-through charging actually does.
Without UPS mode, the safer arrangement is to plug the NAS in only when the outage starts. You will get a hard cut at the moment of plugging, so shut it down first.
Worth having before the trip
- Measuring: plug-in watt meter, to replace the 55 W with your own number.
Common questions
Can I leave the power station plugged in all the time?
Only if the manufacturer describes that as supported. The explainer linked above says pass-through charging and UPS mode are different features, and some units were never built for the UPS role. Check the manual.
Does the router need to stay on if the cable or fiber is down too?
If the modem’s upstream line has no power of its own, the router will run but there is no internet. Count only what you can actually use.
What about a laptop, monitor and a full home office?
That changes the load, not the method. See the home office outage sizing.