How long will a power station run an electric blanket?

One side of a queen electric blanket on a low setting empties a 300 Wh power station in about 4 to 5 hours: that is the only published measurement, and it works out at 60 to 75 watt-hours of station per hour. A full 8 hour night on one side therefore needs about 500 to 600 Wh. A 50 W, 12 volt blanket on the station's DC socket does the same night on about 470 Wh rated.

How many watts does an electric blanket use?#

The rating on the label is what the blanket draws while its element is on. The seven specification sheets and listings below, plus the one measurement, run from 50 W for a car blanket to 300 W for a double heated mattress protector with both sides on.

A 12 volt blanket is a third of a queen blanket's rating, but it is a throw, not a bed cover. Bed blankets are rated for the whole blanket: a queen dual blanket at 150 W in total is about 75 W a side, the same range as the 85 W Sokol measured on one side of his queen; his article does not give its rating.

What one measured night shows#

Mike Sokol, who writes on RV electrics, plugged one side of his queen dual blanket into a Jackery 300 Explorer, set the controller to 30%, and read the station's output. With the inverter on and nothing connected it drew "around 4 watts". With the blanket on, "power draw was around 85 watts most of the time", and the controller cycled on and off. He started at midnight and woke at 5am to "a 0% battery in the Jackery and a cold blanket", and estimates the run at "somewhere between 4 and 5 hours". He gives the Jackery as "rated for 300 watt-hrs of available AC power".

The arithmetic he leaves undone is the useful part. 300 Wh over 5 hours is 60 W on average; over 4 hours it is 75 W. Against the 85 W "on" figure, that is an average of 71 to 88 percent. On a low setting, on one night, the element was on for most of it.

That is one blanket, one night and one station, and the room temperature is not given. A warmer night, a well insulated bed or the lowest setting would give a lower average. But it is a measurement, and it is the only one we found.

Why the 50 percent figure is the wrong one to plan on#

Search for this question and the top results are power station makers' blogs, and they disagree with each other by a factor of two.

• BLUETTI writes that "the thermostat duty cycle is roughly 50%, effectively doubling your expected runtime", so an 80 W blanket for 8 hours costs 320 Wh. It then applies 80 percent inverter efficiency for AC and 90 percent for DC. No test is reported.
• Anker SOLIX gives "Runtime = Battery Capacity / Blanket Wattage", acknowledges the cycling, and recommends planning on the rated wattage. Its example, 500 Wh divided by 100 W for 5 hours, leaves out the inverter loss it mentions in the text.
• OUPES uses a 100 W blanket at constant draw, "100W x 8 hours = 800Wh". No test is reported either.

Sokol's figures sit much closer to the rated-wattage pages than to the 50 percent one. Applied to BLUETTI's own 80 W example, 71 to 88 percent over 8 hours is 455 to 563 Wh at the blanket, not 320. And BLUETTI's method, run on Sokol's setup (300 Wh, 80 percent AC efficiency, 85 W at 50 percent), predicts 5.6 hours. He got 4 to 5.

The 50 percent figure persists because it is a round number nobody had to test, and it doubles the runtime a station appears to deliver. A cold tent or van takes heat out of the bed faster than a bedroom, which pushes the duty cycle up, not down. Plan on 70 to 90 percent of the "on" draw on a cold night, and treat anything better as margin. If you only know the rating, plan on the full rating: that is the conservative version of the same rule, and the one Anker recommends.

Runtime by power station size#

The site models a power station as delivering about 85 percent of its rated watt-hours, the figure the power budget calculator and the power bank sizing guide use. For the measured row we use Sokol's result directly, as station watt-hours per hour, because his 4 to 5 hours already include the inverter and the station's own losses.

The rated rows are the worst case, the element on all the time. The measured row is a low-setting night for one person. For a full 8 hour night, the station sizes that work are:

• One side of a queen, low setting: 500 to 600 Wh rated (8 hours times 60 to 75).
• A 50 W, 12 volt blanket, continuous: about 470 Wh rated (400 Wh divided by 0.85).
• A queen blanket with both sides on high all night: about 1,410 Wh rated (1,200 Wh divided by 0.85).

The timer decides before the battery does#

Auto-off caps runtime whatever the station holds. The Medisana throw stops at 3 hours from a 500 Wh station or a 2,000 Wh one: "Automatic shut-off after 180 minutes". The Car Cozy 2's "30 or 45 minute timer" makes that 12 volt blanket a warm-up device, not an overnight one; no battery size changes it.

The longer timers turn the question around. The timer sets the most a blanket can draw from the station in one switch-on:

Two practical consequences:

• Choose the shortest timer that covers what you need. On a blanket with 1, 3 or 9 hour options, the 3 hour setting caps one side of a queen at about 225 Wh (75 W a side times 3), which a 300 Wh station covers.
• A 12 hour timer is longer than the night. On the BL5151 the battery is what ends the run, so the station size in the previous section is the whole answer. Its listing gives both "75 mins and 12 hour" auto-off without saying which setting each applies to, so check your own controller's manual.

Can you plug an electric blanket into a power station's 12 volt socket?#

Only a 12 volt blanket. A mains blanket, 120 V or 230 V, has to go through the station's AC outlet and therefore through its inverter, and that costs energy twice over.

First, the inverter has an idle draw. Sokol measured "around 4 watts" on the Jackery 300 with nothing plugged in. Over 8 hours that is 32 Wh, about a tenth of a 300 Wh station, spent before the blanket heats anything. Second, the conversion itself loses energy. ResMed's measurements of the same CPAP machines both ways, set out in how long a CPAP runs on a battery, found 14 to 30 percent more draw through an inverter than through a DC converter. A blanket is a different load, so we do not carry that percentage over, but the idle draw applies whatever is plugged in.

A 12 volt blanket on the DC socket skips both. The one full specification here gives 50 W and a maximum current under 4.5 A, with an 8 A fuse in the blanket's own plug; check that against the current your station's 12 volt socket is rated for. The trade is size and heat: it is a throw of 43 by 59 inches, at a third of a queen blanket's rating. For one sleeper in a sleeping bag that may be enough; for a double bed in a van it will not match a queen blanket. A van's fixed auxiliary battery is sized the same way as for a fridge, in 12 volt power and fridges.

Preheat the bed, then turn it down#

A warm bed to get into is cheap. The BL5151 lists a "10 Minute fast heat up"; the current Sunbeam listing starts every switch-on at setting 6, its highest, as a fast preheat.

• Ten minutes at 150 W is 25 Wh. Thirty minutes is 75 Wh. Either is a small fraction of even a 300 Wh station.
• After preheat, drop to the lowest setting or set the shortest timer. The measured low-setting draw for one side is 60 to 75 Wh an hour, against 150 W for both sides of a queen at full rating.
• Then let the sleeping bag or duvet do the work. An electric blanket heats the bed, not you; the insulation keeps the heat. If a bed is cold once the blanket is off, the fix is usually underneath you, as ranked in why you sleep cold.

On this pattern a 300 Wh station covers a 10 minute preheat (about 29 Wh of station, 25 Wh divided by 0.85) and three hours of one side on low (180 to 225 Wh at the measured rate): 210 to 255 Wh in all. A 500 Wh station covers that with margin, or a full night on one side on low.

Measure your own blanket before you trust the table#

1. Plug the blanket into the station at home on the setting you will use at camp, in a room close to the temperature you expect.
2. Read the station's output display with the blanket off (the inverter's idle draw) and on (the "on" draw).
3. Run it for 2 hours from a full charge and read the percentage used. Rated capacity times the percentage drop, divided by 2, is your watt-hours per hour; compare it with the 60 to 75 measured here.
4. Add your other loads in the power budget calculator, and keep 20 percent back for a colder night than the test.

Common mistakes#

Planning on half the rating. The 50 percent duty cycle is an assumption on a power station maker's page. The one measurement found shows 71 to 88 percent on a low setting.

Using a modified sine wave inverter. Sokol warns against plugging an electric blanket into one because "the waveform harmonics can cause the e-blanket controller to melt down", and describes pure sine output as safe. Check the inverter's specification for "pure sine" before plugging in a mains blanket.

Leaving the inverter on for a 12 volt blanket. If the blanket is on the DC socket, switch the AC side of the station off. On the station Sokol tested, 4 W idle is 32 Wh a night for nothing.

Charging a cold station in the morning. A station that sat in a car or tent below freezing should warm up before it charges (the charging limits). For multi-day trips, the recharge figures are in solar for camping.

Frequently asked questions#

How long will a 300 Wh power station run an electric blanket?#

About 4 to 5 hours on one side of a queen dual blanket on a low setting: that is what a Jackery 300 Explorer gave in Mike Sokol's test, with the blanket drawing about 85 W most of the time. With both sides on, or on a high setting, plan on under 2 hours from a 150 W queen blanket. A 50 W, 12 volt blanket on the DC socket runs about 5 hours continuously.

How many watts does an electric blanket use?#

Rated power runs from about 50 W for a 12 volt travel blanket to 120 W for a heated throw, 150 W for a queen blanket with both sides on, and 300 W for a double heated mattress protector with both sides on. The thermostat cycles the element, so the average is lower. One measured night on one side of a queen averaged 60 to 75 W against 85 W while on.

What size power station do I need for an electric blanket all night?#

For one side of a queen blanket on low for 8 hours, 500 to 600 Wh rated, based on the one published measurement. For a 50 W, 12 volt blanket running continuously, about 470 Wh. For a queen blanket with both sides on high all night, about 1,410 Wh. If you preheat the bed and then use a 3 hour timer, a 300 Wh station covers one side.

Is it better to use a 12 volt electric blanket on a power station?#

For runtime, yes. A 12 volt blanket on the DC socket avoids the inverter, which drew about 4 W even with nothing plugged in during a published test, or 32 Wh over 8 hours. The catch is size: the 12 volt blankets found are throws of about 43 by 59 and 58 by 42 inches, the one with a published rating is 50 W, a third of a queen blanket's, and some switch off after 30 or 45 minutes.

Does the auto shut-off limit how long a power station runs a blanket?#

Often, yes. Published timers run from 30 or 45 minutes on 12 volt travel blankets to 3 hours on a heated throw and 9, 10 or 12 hours on bed blankets. With a short timer, the blanket switches off before any reasonable station runs out. With a 12 hour timer the battery is the limit, so size the station from the blanket's draw.

Can I use any inverter to run an electric blanket?#

Use a pure sine wave inverter. Mike Sokol warns that a modified sine wave inverter can cause an electric blanket controller to "melt down" because of the waveform harmonics, and describes pure sine output as being as clean as a household outlet. Check the station or plug-in inverter's specification for "pure sine" before plugging in a mains blanket.