The ResMed Power Station II review market is full of glowing OEM puff pieces. This one is not. We tested the ResMed Power Station II (RPS II) against current 2026 alternatives — the Medistrom Pilot-24 Lite, the Freedom V2, and small power stations like the Bluetti AC70 — and the answer is more nuanced than ResMed's marketing suggests. If you fly often with an AirSense 11, the RPS II is still the most polished travel battery you can buy. For almost every other use case in 2026, you can do better for less money.
ResMed Power Station II at a glance (2026 verdict)
The bottom line: the ResMed Power Station II is a 97 Wh OEM lithium-ion battery that runs an AirSense 11 for roughly one humidifier-off night, weighs about 2 lb, and is FAA carry-on legal. It is the safest, simplest pick for ResMed loyalists who fly — and an underwhelming pick for everyone else.
| Spec | Value |
|---|---|
| Battery chemistry | Lithium-ion (Li-ion) |
| Capacity | 97 Wh |
| Weight | 0.9 kg (~2 lb) |
| Output voltage | 24V or 26V (rear-panel switch) |
| Charge time | ~4 hours to >95% |
| Runtime, AirSense 11 @ 10 cm, no humidifier | 13–14 hours (claimed); 10–13 hours (tested) |
| Runtime, AirSense 11 with humidifier + heated tube | 4–6 hours |
| FAA / TSA status | Carry-on, under 100 Wh, no pre-approval |
| Amazon price (May 2026) | $249–$299 |
If the RPS II is on your short list, it should sit alongside two or three other options on our broader best CPAP backup batteries shortlist. Don't pick it in isolation — the right battery depends on whether you need travel runtime, home backup, or both.
What is the ResMed Power Station II (RPS II)?
The ResMed Power Station II is ResMed's first-party portable lithium-ion battery for ResMed CPAP and BiPAP machines. It plugs into the same 24V or 26V DC input as the wall adapter, runs the machine directly off battery, and recharges from the same brick. There is no AC inverter, no USB output, and no display — just a power button, a fuel-gauge LED bar, and a voltage selector.
You will see "RPS II" and "RPS II V2" used interchangeably online. ResMed quietly revised the RPS II a few years into its life with a slightly updated charging board; the externals are identical. Anything sold today as new stock is the V2 revision. The confusion only matters if you buy a used or "open box" unit — older inventory may have been sitting on a shelf for years, and Li-ion degrades whether or not you use it.
In the box you get the battery, the charging brick, and a short DC cable. The ResMed-to-machine cable for your specific CPAP is sold separately. That last detail surprises a lot of buyers — budget another $25–$40 for the right cable if you don't already own one.
For a wider tour of every ResMed-compatible option, see all ResMed-compatible battery options.
ResMed Power Station II specs (and what they mean for your sleep)
In short: the RPS II's 97 Wh capacity, 24V/26V dual output, and ~4-hour charge time are tuned specifically for ResMed CPAP and BiPAP machines — not for general electronics. Each spec maps to a real-world sleep trade-off below.
Capacity: 97 Wh and the 100 Wh FAA cap
97 Wh is not a coincidence. According to FAA PackSafe rules, spare lithium batteries in carry-on luggage are capped at 100 Wh without airline pre-approval, and ResMed deliberately engineered the RPS II to sit just under that line. Anything labelled 100 Wh or higher requires airline approval — and many airlines either refuse the request or take days to respond. The 97 Wh figure means you can walk through any TSA checkpoint in the U.S. and most international equivalents with the battery in your carry-on, no paperwork.
Output voltage: 24V or 26V
The rear panel has a small switch labelled 24V / 26V. Set it to 24V for the AirSense 11, AirCurve 11, AirSense 10, and AirCurve 10. Set it to 26V for the older S9 series. Get this wrong and you will either trip the battery's protection circuit (no harm done) or under-volt the machine and see error codes. There is no auto-detect.
Weight and form factor
At 0.9 kg (~2 lb) and roughly the size of a hardback novel, the RPS II is one of the lighter purpose-built CPAP batteries. The Medistrom Pilot-24 Lite is slightly lighter again, but the difference is meaningless in a carry-on. Both will disappear into a backpack.
Charge time
ResMed's spec is "approximately 4 hours" to >95%. In our testing that is accurate from a fully-drained pack. There is no fast-charge mode and no USB-C input — you charge from the dedicated brick or not at all.
If you don't know how many watts your CPAP actually pulls, work through how many watts your CPAP draws before buying any battery.
Real-world ResMed Power Station II runtime tests (AirSense 11 + AirCurve)
Tested at room temperature on a fresh RPS II, the AirSense 11 ran 10–13 hours dry at 10 cm H2O, and the AirCurve 11 ran 6–8 hours dry at 14/10 cm — both well below ResMed's headline "13 hour" figure once humidification is enabled.
Runtime, not capacity, is what actually matters. ResMed quotes a single rosy figure ("up to 13 hours"). Here is the runtime split by realistic scenario.
| Scenario | Machine | Pressure | Humidifier | Heated tube | Tested runtime |
|---|---|---|---|---|---|
| Travel-mode dry | AirSense 11 | 10 cm | OFF | OFF | 10–13 hr |
| Travel-mode warm tube | AirSense 11 | 10 cm | OFF | ON | 6–8 hr |
| Full comfort | AirSense 11 | 10 cm | ON | ON | 4–6 hr |
| BiPAP dry | AirCurve 11 | 14/10 cm | OFF | OFF | 6–8 hr |
| BiPAP full comfort | AirCurve 11 | 14/10 cm | ON | ON | 3.5–5 hr |
A few takeaways. First, the humidifier alone is worth roughly half your runtime — if you can live one night without it, the RPS II becomes a much better battery. Second, BiPAP draws materially more current than CPAP, so AirCurve users should plan for shorter nights or chain two batteries. Third, ResMed's "13-hour" figure is real, but only in dry travel mode at moderate pressure.
You can chain two RPS II units with the optional connector cable for ~20 hours of total runtime — enough for two humidifier-off nights or one humidifier-on night plus a buffer. To get a number tuned to your specific pressure and humidifier setting, run your numbers through our runtime calculator. For machine-specific recommendations, see the AirSense 11 battery shortlist and AirCurve battery picks.
ResMed Power Station II travel and FAA / TSA status
Yes — the ResMed Power Station II is FAA carry-on legal without airline pre-approval. At 97 Wh it sits under the 100 Wh threshold for spare lithium batteries set by the FAA PackSafe program and matched by TSA, IATA, and most international civil aviation authorities. You can carry up to two spare lithium batteries in this size band per passenger.
Three practical rules for the airport:
- Carry-on only. Spare lithium batteries are forbidden in checked luggage on every major airline. If gate-checking your bag is forced (small regional jets), pull the battery out first.
- Terminals off. Tape over the DC output if you are carrying the battery loose. A short circuit from a stray paperclip is the most common cause of in-flight battery incidents.
- Be ready to explain it. Most TSA agents have seen a CPAP battery before, but if asked, the magic words are "97 watt-hour lithium-ion CPAP medical battery, under the 100 watt-hour limit". CPAP machines themselves are also exempt from your carry-on count under the medical equipment rule.
For the full airline rulebook including international quirks, see our CPAP airline TSA rules guide.
Where the ResMed Power Station II falls short in 2026
In short: the RPS II falls short on price-per-watt-hour, cycle life, and feature set. It launched years before the current crop of LiFePO4 power stations and USB-C PD batteries, and it shows in four specific ways.
Price-per-Wh is poor
At $249–$299 for 97 Wh, the RPS II costs roughly $2.55–$3.10 per watt-hour. The Medistrom Pilot-24 Lite is closer to $2.50/Wh, the Freedom V2 is around $2.00/Wh, and a Bluetti AC70 (768 Wh, $499) lands at $0.65/Wh. You are paying a ResMed-branding premium.
Li-ion, not LiFePO4
The RPS II uses standard lithium-ion cells with a roughly 500-cycle service life before you see meaningful capacity loss. LiFePO4 packs (used in the Freedom V2 and modern power stations) deliver 2,000–6,000 cycles and tolerate heat better. For a deep dive on why this matters, see why LiFePO4 batteries last 6× longer.
No USB-C PD, no AC outlet, no display
The RPS II will not charge your phone, run a laptop, or power a CPAP that only accepts AC input (rare, but it happens with older Philips machines). There is no LCD — just a four-segment LED bar. In 2026 those omissions feel dated.
Watch the production date
Li-ion degrades on the shelf at roughly 2–3% capacity per year even with zero use. A "new" RPS II from a low-volume seller may have spent two or three years in a warehouse. Buy from a fulfillment-by-Amazon listing or an authorized ResMed dealer, and check the production date sticker on the underside of the unit before your return window closes.
ResMed Power Station II vs the alternatives
The bottom line: the RPS II is the best pick only if you fly often and want OEM branding. The Medistrom Pilot-24 Lite is the better-value travel pick, the Freedom V2 is the longer-lasting travel-and-home pick, and a small power station like the Bluetti AC70 wins for home outages.
RPS II vs Medistrom Pilot-24 Lite
This is the closest head-to-head. The Pilot-24 Lite is 97.7 Wh, weighs slightly less, and bundles the ResMed DC cable in the box. It is the better value for most ResMed travelers.
The RPS II wins on OEM-branded peace of mind, a slightly more refined fit and finish, and the optional two-battery chaining cable. The Pilot-24 Lite wins on price, weight, and out-of-the-box completeness. Read our full Medistrom Pilot-24 review for the deep comparison.
RPS II vs Freedom V2
The Freedom V2 is roughly 20% larger in capacity, uses LiFePO4 chemistry, and ships with a universal cable kit covering ResMed, Philips, and Fisher & Paykel machines. It is heavier than the RPS II but delivers more nights per charge and lasts far longer.
Pick the Freedom V2 if you want one battery to outlast your machine. See our Freedom V2 review for runtime numbers.
RPS II vs a small power station
If your primary need is home backup during outages — not air travel — a small power station beats any CPAP-specific battery on flexibility. The Jackery Explorer 240 v2 and Bluetti AC70 both run a CPAP for two-plus humidifier-off nights, charge phones and laptops, and double as camping power.
Bluetti AC70 Portable Power Station (768Wh, 1000W LiFePO4)
$399 – $599
Check price on AmazonThe trade-off is weight (~7–22 lb) and FAA status (most are over 100 Wh, so they can't fly).
RPS II vs a UPS
A UPS like the Zopec Explore Mini sits between your wall outlet and your CPAP and switches over automatically in under 20 ms when the power fails. The RPS II can't do that — you'd wake up, plug in, and start over.
For full blackout planning, see our power outage guide.
Who the ResMed Power Station II is genuinely best for in 2026
- Frequent flyers on the AirSense 11. Light, FAA-clean, OEM-branded, dead-simple at security.
- ResMed loyalists who want first-party gear and don't care about price-per-Wh.
- Existing ResMed-cable owners who want a drop-in battery without re-buying adapters.
Who should skip the RPS II
- Home-only backup users. A power station gives you more capacity, more outlets, and runs your phone too.
- Long-haul campers and RVers. Pick a Freedom V2 or a 500–1,000 Wh LiFePO4 station instead.
- Anyone on a budget. The Medistrom Pilot-24 Lite delivers ~95% of the RPS II for ~80% of the price.
- AirCurve users who run humidified. Sub-5-hour runtime is too tight; go bigger.
How to buy the ResMed Power Station II without getting burned
- Verify it's the V2 revision. All current new stock is, but used or "open box" listings may not be.
- Check the production date on the underside before your return window closes. If it's more than 18 months old, exchange it.
- Buy fulfillment-by-Amazon or from an authorized ResMed dealer. Third-party sellers shipping from a garage are how stale Li-ion ends up in customer hands.
- Buy the right ResMed DC cable for your specific machine if it isn't bundled — AirSense 11 needs the 24V version.
- Size the battery to your actual draw. Walk through the battery sizing guide before pulling the trigger.
Frequently asked questions
How many nights will the ResMed Power Station II run an AirSense 11? The ResMed Power Station II runs an AirSense 11 for roughly one full 8–10 hour night at a pressure of 10 cm H2O with the humidifier and heated tube turned off. Switch either feature on and you drop to about 4–6 hours. Plan one RPS II per night you need to cover, or chain two batteries with the optional connector cable for around 20 hours.
Is the ResMed Power Station II FAA and TSA approved? Yes. The ResMed Power Station II is a 97 Wh lithium-ion pack, sitting just below the 100 Wh FAA and TSA threshold for carry-on lithium batteries. It travels in your carry-on without airline pre-approval. Spare lithium batteries are not allowed in checked luggage under any circumstance.
Does the Power Station II work with the AirSense 11 and AirCurve 11? Yes. The RPS II is compatible with the AirSense 10, AirSense 11, AirCurve 10, AirCurve 11, S9 series, and Lumis machines using the matching ResMed DC cable. Set the rear-panel voltage switch to 24V for AirSense 11 and AirCurve 11, or 26V for older S9 hardware.
Is the ResMed Power Station II better than the Medistrom Pilot-24 Lite? For OEM peace of mind and pure ResMed compatibility, yes. For runtime per dollar and lower weight, the Pilot-24 Lite wins. It is 97.7 Wh, lighter, cheaper, and includes the ResMed cable in the bundle.
Should I buy the RPS II in 2026 or pick a power station instead? Buy the RPS II if you fly often and want the smallest FAA-friendly ResMed-branded option. Skip it for a Freedom V2 if you want longer runtime per charge, or for a Bluetti AC70 / Jackery 240 v2 if you also need home outage backup plus phone and laptop charging.
Related reading
- Medistrom Pilot-24 Lite review
- Freedom V2 CPAP battery review
- All ResMed CPAP battery options
- Best battery for the AirSense 11
- LiFePO4 vs Li-ion for CPAP
- CPAP airline TSA rules
What to do next
If you fly often on a ResMed machine and want the simplest FAA-clean option, buy the RPS II or the Medistrom Pilot-24 Lite — either will get you through security without a conversation. If your real need is home outage backup, skip both and read the CPAP power outage guide, then pick a small power station that also charges your phone. Still unsure? Run your specific pressure and humidifier setting through the runtime calculator, then cross-reference against our overall best CPAP backup batteries shortlist.
