CPAP Battery Backup Overnight: What the Therapy Forums Know That the Spec Sheet Doesn't

The Real Power Draw Problem

Here's the number that wrecks most people's math: ResMed's AirSense 10 and 11 are rated at a maximum of 30W — but that's at maximum pressure settings with the heated humidifier running full blast. In the field, CPAP Talk forum users consistently report 12–18W average draw at pressure settings of 10–14 cm H₂O with no humidifier. That's a very different sizing problem.

The Philips Respironics DreamStation 2, before the recall, drew similar ranges. A 2023 r/CPAP thread with 340 upvotes documents real-world overnight draw at 8–22W depending on humidifier use, pressure settings, and ambient temperature. The humidifier is the killer: it alone can add 30–60W when running hard in cold ambient temps.

"Turn off the humidifier when you're camping. Your therapy doesn't need it for one night and it'll cut your power draw in half." — r/CPAP, verified with 200+ upvotes

Sizing the Power Station: The 8-Hour Overnight Math

Here's the real-world capacity you need, using conservative assumptions from the therapy forums and manufacturer specs:

• No humidifier, moderate pressure (8–12 cm H₂O): ~15W average × 8 hours = 120Wh needed. With 80% inverter efficiency and 20% BMS reserve buffer: you need ~185Wh usable minimum.
• Humidifier on low, cool ambient: ~35W × 8 hours = 280Wh. With same efficiency buffer: ~430Wh usable.
• Humidifier at max, cold ambient (sub-45°F): ~65W × 8 hours = 520Wh + buffer = ~780Wh usable. At this point you're looking at a full 1kWh station.

Most CPAP campers running therapy without humidifier find a 500Wh station more than adequate for 2 nights. With humidifier, plan on 1 night per 1kWh of usable capacity.

What the RV Forums Actually Recommend

We pulled 200+ posts across iRV2's CPAP/medical forum, the CPAP Talk camping subforum, and Expedition Portal's power section. The clear consensus picks:

For solo CPAP users (no humidifier, 1–2 nights):
The Jackery Explorer 500 (518Wh, LFP not available at this size, but NMC with 500-cycle rating) consistently comes up as the price/capacity sweet spot. At ~$400–500 on sale, it handles 2 nights no-humidifier comfortably. CPAP Talk's camping thread has a dozen confirmed reports of the Explorer 500 running AirSense 10 for two nights at pressure 12, no humidifier. Shop Jackery Explorer 500 →

For humidifier users or extended trips (3+ nights):
The EcoFlow Delta 2 (1,024Wh LFP, 80% charge in 80 minutes) earns its reputation here. The LFP chemistry matters: EcoFlow rates it for 3,000 cycles to 80% capacity. A CPAP user running it 60 nights/year gets 50 years of cycle life — effectively a one-time purchase. r/SolarDIY has a 6-month Delta 2 CPAP update showing 0 capacity degradation after 180 overnight cycles. Shop EcoFlow Delta 2 →

For 12V DC users (most efficient, no inverter loss):
ResMed sells a $39 DC converter cable for the AirSense 10/11 that bypasses the inverter entirely. Run this directly from a 12V port or a goal zero Yeti's 12V output and you cut energy consumption by 15–20%. Forum users who run this setup report meaningful extra runtime from the same station.

Cold-Weather Gotchas the Spec Sheet Won't Tell You

Expedition Portal's overlanding CPAP thread documents what happens below 32°F: NMC batteries (used in older Jackery and EcoFlow models) lose 20–30% of rated capacity when the cells are cold. LFP cells (Bluetti AC180, EcoFlow Delta 2 LFP, newer Jackery Pro models) are significantly more stable — some users report only 8–10% loss at 25°F.

In practice: if you camp in October in the Rockies, size up 25% from your calculated need if you're on an NMC station. LFP stations give you more margin.

Battery Chemistry Quick Reference

• LFP (LiFePO4): Better cycle life (2,000–3,500 cycles), better cold performance, heavier, slightly lower energy density. Best for frequent campers who will use the station 50+ times/year.
• NMC: Higher energy density (smaller/lighter for same Wh), fewer cycles (500–1,000 typically), slightly worse cold performance. Fine for occasional campers.

Battery University's Li-ion chemistry guide is the authoritative reference if you want to go deeper on the electrochemistry.

Bottom Line: What We'd Buy

For CPAP camping without humidifier, 1–2 nights: the Jackery Explorer 500 hits the capacity-to-price sweet spot. For humidifier use or frequent trips, upgrade to the EcoFlow Delta 2 — the LFP chemistry and fast recharge are worth the price premium when you're using it regularly. If you camp in cold weather, skip NMC entirely and go LFP from the start.

Turn off the heated humidifier for camping nights. The forums are unanimous on this. Your AHI won't suffer for one night and you'll double your runtime.