Will an Electric Blanket Drain a Car Battery?

Yes, an electric blanket can drain a car battery, especially if used for an extended period while the vehicle is off. This is particularly relevant for cold weather conditions when extra heating might be required. This article explores why an electric blanket can deplete a car battery and provides some key points and alternatives to mitigate this issue.

Understanding Power Consumption

Electric blankets require a significant amount of power to operate, with most models consuming around 60 to 100 watts. Running an electric blanket for several hours can draw a considerable amount of power from the car battery. The average car battery typically has a capacity of about 50 to 70 amp-hours. According to calculations, an electric blanket consuming 100 watts draws approximately 8.3 amps at 12 volts. Running such a blanket for just a few hours can significantly reduce the battery charge.

Alternatives to Using an Electric Blanket

If you need warmth in a car without the engine running, here are some alternative options:

Running the Engine: A short run of the engine can help recharge the battery. However, this is only practical for brief periods. Portable Power Station: Utilizing a portable power station designed for such applications can be a more sustainable solution. In-Vehicle Charging Options: Some newer electric or hybrid vehicles come with 110V outlets or auxiliary power outlets. For example, the Cybertruck will feature such an outlet in 2021. Additional adaptors can be used to connect to the 12V auxiliary outlet, commonly known as the “cigarette lighter type.”

Testing the Draw on Your Car Battery

If you plan to test the effect of an electric blanket on your car battery, here are some steps to follow:

Initial Check: Note the percentage or miles of travel remaining in your car’s battery while sitting in the garage. This will serve as your baseline. Connection Test: Carefully connect the electric blanket to the car’s 12V auxiliary outlet and run it for 30 minutes. This should give you a rough estimate of the draw. Analyze Results: Take note of the new percentage or miles of travel remaining. Multiply the difference by two to estimate the draw per hour of use.

As a reference, if your Tesla’s heat settings draw around 4 to 6 amperes per hour, an electric blanket for a full-size bed would likely draw about half that, around 2 amperes per hour. This estimate provides a starting point, but precise readings depend on the actual model and settings of your electric blanket and vehicle.

It's also worth noting that if you leave a vehicle running while idling, it can deplete the fuel tank, leading to potential problems. Idling for extended periods can also lead to engine wear and increased emissions.

Conclusion

While it’s possible to use an electric blanket in a vehicle, doing so without running the engine can lead to a drained battery. It’s crucial to balance the need for warmth with the car's power needs. Consider alternative methods such as using a portable power station or leaving the engine running for short periods. Understanding the power consumption and capacity of your vehicle's battery can help you avoid unexpected issues.