EcoFlow is one of the most popular power station brands for CPAP users, and for good reason: every model in the lineup outputs pure sine wave AC, charges fast enough to be useful in a multi-day outage, and offers a bedside UPS mode that keeps your therapy running through a blackout. The question most CPAP users actually have is narrower — which EcoFlow lasts all night, and which one is overkill? This guide walks through EcoFlow for CPAP by model, with runtime calculated directly from each unit's rated watt-hours and realistic CPAP power draw, so you can match the right battery to your machine instead of guessing.
Why EcoFlow works well for CPAP
EcoFlow power stations are a strong match for CPAP because they deliver pure sine wave AC power, the exact waveform a CPAP's electronics and blower motor are designed to receive. Cheaper "modified sine wave" inverters can cause buzzing, erratic flow data, or premature wear on sensitive medical electronics. Every EcoFlow — RIVER 2, RIVER 2 Max, RIVER 2 Pro, and DELTA 2 — uses a true pure sine inverter, so your machine runs exactly as it would on wall power.
The second reason is the AC outlet plus DC output flexibility. You can plug your CPAP's standard power brick into the EcoFlow AC outlet, or, if your machine supports it, run a DC cable straight from the unit's car-style 12V port to bypass the inverter entirely. Running on DC skips the inverter conversion step and typically extends runtime by 15–25%, which matters a lot on a smaller battery like the RIVER 2.
EcoFlow also uses LiFePO4 (lithium iron phosphate) cells in the RIVER 2 series and DELTA 2, rated for roughly 3,000+ charge cycles to 80% capacity. For a nightly bedside battery, that translates to years of service before noticeable degradation. The trade-off is that EcoFlow units run a small internal cooling fan under load. At the low wattage a CPAP draws the fan is usually quiet or off, but it is worth knowing before you put one on your nightstand — see the noise note in the model section below.
One important setup detail: leave X-Boost off when powering a CPAP. X-Boost is EcoFlow's feature that lets a small inverter run higher-wattage resistive devices by subtly altering the output waveform. It is great for a hair dryer, but for sensitive CPAP electronics you want the cleanest possible sine wave, so disable X-Boost in the EcoFlow app before relying on the unit overnight.
Runtime by model and CPAP machine
How long an EcoFlow runs your CPAP comes down to two numbers: the battery's usable watt-hours and your machine's average power draw. The math is simple — usable watt-hours ÷ average watts = hours of runtime — and it is the most honest way to compare models without a marketing filter.
Start with usable capacity. A power station's rated watt-hours are not all reachable; inverter overhead and conversion loss eat roughly 15%, so multiply the rating by about 0.85 to estimate real-world usable energy:
- RIVER 2 — 256Wh rated, ~218Wh usable
- RIVER 2 Max — 512Wh rated, ~435Wh usable
- RIVER 2 Pro — 768Wh rated, ~653Wh usable
- DELTA 2 — 1024Wh rated, ~870Wh usable
Next, your CPAP's draw. A typical CPAP without the heated humidifier and heated tube draws about 20–30 watts; we'll use 25W as a representative average. Switch the heated humidifier on and average draw roughly doubles to 40–60W, because the heating plate is the single hungriest component in the system. We'll use 50W for the humidifier scenario. Your exact numbers depend on pressure setting, machine model, and humidity level — our CPAP power consumption guide explains how to find your own.
Here is the calculated runtime for each EcoFlow at those two draw levels:
| EcoFlow model | Usable Wh | No humidifier (~25W) | Heated humidifier (~50W) |
|---|---|---|---|
| RIVER 2 (256Wh) | ~218 Wh | ~8–9 hrs (1 night) | ~4–4.5 hrs (partial) |
| RIVER 2 Max (512Wh) | ~435 Wh | ~17 hrs (2 nights) | ~8–9 hrs (1 night) |
| RIVER 2 Pro (768Wh) | ~653 Wh | ~26 hrs (3 nights) | ~13 hrs (1.5 nights) |
| DELTA 2 (1024Wh) | ~870 Wh | ~34 hrs (4 nights) | ~17 hrs (2 nights) |
The pattern is clear. Without the humidifier, the RIVER 2 covers a single full night and the DELTA 2 stretches to roughly four nights. Turn the humidifier on and every estimate is cut nearly in half — the RIVER 2 no longer makes it to morning, while the DELTA 2 still covers two nights. This is the most important takeaway for sizing: the humidifier, not the model, is usually what decides whether you wake up to a working machine.
If your numbers fall between these scenarios, plug your real watts into our CPAP battery runtime calculator for a tailored figure. And if you are tempted to keep the humidifier running off-grid, read why that drains batteries so fast in our CPAP humidifier battery drain breakdown — turning the heater off and using a hose cover instead is the single biggest runtime win you can make.
Stretching runtime with DC and humidifier-off
Two adjustments dramatically extend any EcoFlow's CPAP runtime. First, run your machine on DC if it supports a 12V/24V CPAP cable — bypassing the inverter recovers the ~15% conversion loss, effectively giving the RIVER 2 the usable capacity it's rated for. Second, turn the heated humidifier and heated tube off for battery nights. Together these two moves can nearly double how many nights a single charge lasts.
The UPS mode advantage for bedside use
EcoFlow's UPS mode is the feature that makes it a genuine bedside CPAP backup rather than just a portable battery. In UPS mode the EcoFlow stays plugged into the wall and passes grid power straight through to your CPAP, while keeping the battery topped off; the instant the grid drops, it switches to battery in under 30 milliseconds — fast enough that your CPAP never registers the interruption and keeps blowing without a reboot.
That sub-30ms switchover is the number that matters. A CPAP blower spinning at therapy pressure will momentarily stall and restart if power cuts out even briefly, and a restart can mean a few seconds of no airflow plus a startup ramp. With true UPS pass-through, you sleep through the outage entirely and only learn about it in the morning. This is the same protection a dedicated UPS gives a desktop computer, applied to your therapy.
To use it, plug the EcoFlow into the wall, plug your CPAP into the EcoFlow's AC outlet, and enable UPS mode in the EcoFlow app. The unit now acts as an always-charged buffer between the grid and your machine. One caveat worth understanding: EcoFlow's standard UPS is an "offline" or standby UPS, meaning there is a brief switchover rather than zero gap, but the under-30ms window is well inside what a CPAP tolerates without interrupting therapy. For the vast majority of home outages this is exactly the behavior you want.
A practical bedside note: leave the unit's screen timeout short and X-Boost off so the only sound at night is the very quiet cooling fan, which on most units stays off entirely at CPAP-level wattage. Keep the EcoFlow on a hard surface with clearance around the vents so it can shed heat silently.
EcoFlow vs dedicated CPAP batteries
A dedicated CPAP battery (like a Medistrom Pilot or similar lithium pack) is smaller, lighter, and purpose-built, but an EcoFlow power station does far more for a similar or lower cost-per-watt-hour. The right choice depends on whether you prioritize portability or versatility.
Dedicated CPAP batteries win on weight and travel friendliness. A purpose-built pack might weigh 1.5–2 lbs and slip into a CPAP travel bag, and many are sized to clear airline carry-on watt-hour limits (under 100Wh, or 160Wh with airline approval). They are the better pick for tent camping and air travel where every ounce counts. The downside is that they only power your CPAP, often at modest capacity, and command a premium for the medical-specific form factor.
EcoFlow power stations win on versatility, capacity, and value. The same RIVER 2 that runs your CPAP overnight also charges phones, runs a CPAP plus a fan, powers a mini fridge of medication, or keeps a router online during an outage. You get UPS pass-through, fast recharging, and far more watt-hours per dollar. The trade-offs are size and weight — a DELTA 2 weighs around 27 lbs — and the fact that, unlike a sub-100Wh medical pack, the larger EcoFlows exceed airline carry-on battery limits.
The bottom line: if your priority is grab-and-go air travel, a small dedicated CPAP battery is hard to beat. If you want home outage protection, multi-night camping, hurricane readiness, and a battery that does more than one job, an EcoFlow is the better value. Our best CPAP backup batteries comparison puts both categories side by side.
Which EcoFlow model to buy for your CPAP
The right EcoFlow depends on one decision above all: do you run the heated humidifier on battery, and how many nights do you need to cover? Match your answer to the runtime table above and the choice gets simple.
- RIVER 2 (256Wh) — single night, humidifier off. The lightest and cheapest option, ideal as a bedside UPS for home outages or one night of camping with the humidifier off. Covers roughly one full night at ~25W. Not enough if you insist on heated humidification overnight.
- RIVER 2 Max (512Wh) — one humidifier night or two dry nights. The sweet spot for most users. It covers a full night with the heated humidifier, or about two nights without, and still recharges quickly. If you want a single battery that handles humidified therapy through one outage, start here.
- RIVER 2 Pro (768Wh) — long-weekend coverage. Roughly 1.5 humidified nights or three dry nights — a good fit for weekend trips and longer outages where you want margin.
- DELTA 2 (1024Wh) — multi-night and whole-system backup. About two humidified nights or four dry nights, plus enough headroom to run other devices. This is the hurricane and extended-outage pick, and it's expandable with an add-on battery if you need even more.
On recharge speed, EcoFlow is a standout. The DELTA 2 charges from 0–80% in roughly 50 minutes on AC, and the RIVER 2 series fully recharges in about an hour — so if the grid blinks back on, or you reach a generator or wall outlet during the day, you can top up before the next night. The RIVER 2 series and DELTA 2 also accept solar input (typically up to 110W–500W depending on model), which turns any of them into a renewable multi-day solution; see our solar charging guide for CPAP for panel sizing.
A word on noise, since these sit beside your bed. EcoFlow units use an internal cooling fan that spins up under heavy load or during fast charging, but a CPAP's 25–50W draw is light enough that the fan usually stays off or barely audible overnight. The exception is recharging: if you top the unit up while sleeping, the fan will run, so schedule charging for the daytime when possible. Place the EcoFlow on a hard, ventilated surface rather than soft bedding so it can dissipate heat passively and keep the fan idle. With humidifier off, X-Boost off, and no active charging, a bedside EcoFlow is effectively silent.
For everyone, the universal settings are the same: X-Boost off, UPS mode on for bedside use, humidifier off to maximize runtime, and DC power if your machine supports it. Those four choices matter more than which model you buy.
Related reading
- CPAP Battery Backup Guide
- Jackery vs EcoFlow for CPAP
- CPAP Battery Sizing Guide
- Best CPAP Backup Batteries of 2026
- Bluetti for CPAP
What to do next
Pick your model based on one question: do you need the heated humidifier overnight? If yes, size up to at least the RIVER 2 Max; if you run dry, the RIVER 2 covers a night and the DELTA 2 covers several. Set X-Boost off, enable UPS mode, and you have a bedside backup that switches over in under 30 milliseconds. If you're ready to pick a battery, check our best CPAP backup batteries guide for side-by-side comparisons.
