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The number on your electric blanket’s tag is not what it draws all night, and the number on your power station’s box is not what you get out of it. Both figures mislead in the same direction — they make the math look worse than it is, and they bury the two problems that actually matter.
The reassuring truth first: a thermostatic blanket cycles its heating element on and off, so it almost never runs at rated power for hours on end. People who’ve actually tested this — running a blanket all night off a portable station — find the energy use is surprisingly modest. The worrying truth: a modified-sine-wave inverter can silently destroy your blanket’s controller, and every AC power station leaks some capacity through inverter losses before a watt ever reaches your blanket. Get those two things right and the sizing math mostly takes care of itself.
What the Blanket Actually Draws
On low or medium, a single-zone electric blanket typically pulls somewhere in the 50–100W range. Turn it to high and you can see 200W or more. A metered test of one side of a queen blanket at a 30% controller setting came in at 85W; a separately tested two-zone queen at a mid-level setting measured 90W. Those numbers sit comfortably inside the ranges the manufacturers publish, which is a good sign — here the spec sheets aren’t lying, they’re just describing the ceiling, not the average.
The ceiling matters because of the thermostat. Once the blanket reaches temperature, the element stops drawing. Real all-night consumption is well below the peak rating — the element is off more than it’s on once you’re warm. Cold ambient temperatures force longer duty cycles, which pushes consumption closer to the rated draw, but a mild night means the blanket barely works to maintain heat.
Two things can double your load without any obvious signal:
- High heat settings — the element runs longer cycles and the on-time wattage itself is higher.
- Dual-zone blankets — a “dual” or “partner” blanket is effectively two independent heating elements. Both sides running simultaneously roughly doubles the draw compared to a single-zone setup.
Always know which of these you’re dealing with before you size anything. Quoting runtime figures without specifying single-zone versus dual-zone is the single most common way these numbers mislead.
The Two Hidden Taxes on Your Power Station
Your power station’s nameplate capacity — the big Wh number on the side — is the energy stored in the battery. It is not what arrives at your blanket. Two losses eat into it before a watt does any warming.
Inverter conversion loss. Your blanket runs on AC. The power station stores DC. Converting between them isn’t free — expect to lose roughly 10–20% through that process, which means a 300Wh station realistically delivers something closer to 80–90% of its nameplate capacity to an AC load. Cold weather compounds this by reducing the battery’s own output.
Inverter idle draw. Keeping the inverter awake costs power even when the blanket’s element is off. A metered test of a Jackery 300 found the inverter drawing around 4W at idle with no active load. Over an 8-hour night, that’s over 30Wh — roughly 10% of that station’s nameplate capacity, gone before the blanket draws a watt. On a larger station the percentage is smaller, but the principle holds: the clock is running even when the element isn’t.
DC blankets — the 12V variety common in overlanding and RV use — sidestep both of these entirely by plugging directly into the battery through a DC port. That’s why a Goal Zero Yeti 200X (roughly 187Wh) ran a 12V blanket for 8 hours with 23% charge remaining: almost nothing was lost to conversion. The same station running a 120V AC blanket would have drained considerably faster. When you see runtime figures online, the AC-versus-DC distinction is usually the invisible variable making the numbers look inconsistent.
The Waveform Problem Nobody Mentions
This one is less about runtime and more about whether your blanket survives the night.
Most quality portable power stations output pure sine wave AC — the same clean waveform as a wall outlet. Some older, cheaper, or non-dedicated inverters output modified sine wave, which is a stepped approximation. For resistive loads like a simple space heater, modified sine wave usually works fine. For the electronic controller in a modern electric blanket, it can cause the power supply to overheat and melt down.
The failure is insidious because the blanket may power on and appear to work normally while the controller is quietly being damaged. An RV electrical specialist who has metered and tested this equipment is the source here, and no other source in this research contradicts it — the warning simply doesn’t appear in most blanket-runtime guides because those guides are written around the runtime math, not the hardware.
The practical check is quick: look for “pure sine wave” in your power station’s specs. Reputable stations from Jackery, EcoFlow, Goal Zero, and similar brands are virtually all pure sine wave. If you’re unsure about a unit, check before you run the blanket overnight, not after the controller smells like burnt plastic.
How Long Will It Actually Run?
The tested data — as opposed to vendor arithmetic — gives you the most reliable anchors:
- A Jackery 300 (roughly 300Wh) ran one side of a queen blanket for 4–5 hours to complete depletion, metered.
- A Goal Zero Yeti 200X (roughly 187Wh) ran a 12V DC blanket for 8 hours with charge still remaining — DC’s efficiency advantage is the whole story there.
- A Jackery 1000 (roughly 1000Wh) ran a 110V AC blanket through a full night — starting on high for 15–20 minutes then dropping to low or medium — and used under 40% of its capacity by morning.
That last one is the reassuring data point: a thousand-watt-hour station and a thermostating blanket used sensibly is not a close call. The blanket is not a hungry load the way an air fryer or a coffee maker is. The thermostat does most of the work for you.
Vendor-calculated runtimes — “this station will run a 100W blanket for 20+ hours” — are arithmetic, not measurement. They’re not wrong in method, but they assume nameplate wattage drawn continuously with no losses, which isn’t how a thermostating blanket actually behaves. Use them as a rough upper bound, not a promise.
Sizing for a Full Night
The formula is simple; the inputs are what require honesty:
Usable Wh needed = average draw (W) × hours × ~1.2 buffer
The buffer covers inverter conversion loss and idle draw. Apply it to usable capacity, not nameplate — for most lithium-chemistry portable stations, usable capacity is close to nameplate (lithium can discharge deeply). For lead-acid setups, it’s a different story entirely.
What changes the answer most:
- Single zone vs. dual zone: single side at medium, maybe 85–90W average; both sides of a dual blanket, potentially double that.
- Heat setting and ambient temperature: a cold night forces longer heating cycles, pushing average draw up toward the rated wattage.
- AC vs. DC blanket: a 12V DC blanket skips the inverter taxes entirely and effectively gets you 20–30% more runtime from the same battery.
- How many hours: a full 8–9 hour sleep is not the same as a 5-hour nap.
Plug realistic numbers — average draw rather than peak rating, honest hours — and the sizing usually lands somewhere between 500Wh (mild night, single zone, DC blanket) and 1000Wh (cold night, both zones, AC). A nominal 1000Wh station is the comfortable floor for AC use across a full night without rationing; smaller stations work for shorter durations or with a DC blanket.
A Note on Battery Chemistry and Amp-Hour Labels
If you’re sizing off a traditional battery rather than a purpose-built power station, amp-hour labels are not the whole story. Multiply by voltage to get watt-hours — and then check the chemistry.
A 100Ah lithium battery can discharge to near zero, delivering close to its full watt-hour rating. A 100Ah lead-acid battery should only be discharged to about 50% depth to protect its life, which means roughly half the available energy. Same label, half the usable capacity. A metered comparison of those two setups running one side of a blanket found the lithium battery delivered roughly double the runtime from an identical amp-hour rating. If you’re working with a lead-acid bank and wondering why the math isn’t adding up, the 50% depth-of-discharge ceiling is almost always the answer.
The One Thing to Remember
Size on average draw, not peak rating — your blanket’s thermostat is already doing you a favor. Then make sure your station outputs pure sine wave, account for the inverter’s cut, and use tested runtimes (not vendor calculations) as your anchors. Do those three things and an overnight run is far less of a guessing game than the spec sheets make it look.