Today I tested an electric car heater under the cigarette lighter. As you can see in the video, this device has a rather poor performance and it takes a long time to defrost the glass. However, it will always help in severe frosts.
You can buy the heater here: https://s.click.aliexpress.com/e/_AEQFtQ
See also my other films:
Chinese 8kw diesel webasto test: • Chinese garage webasto 12V 8KW Test U...
Webasto power consumption: • How much electricity does Chinese 8KW...
How to connect the Sharan webasto: • How to connect the D3WZ webasto brief...