USB ports vs. cigarette lighters in cars

On this blog post (in Italian), Giovanni Fontana wonders why cars still have a cigarette lighter instead of standard power sockets. Most people, he argues, need to connect portable devices to charge than to light up cigarettes, and sockets should at least be an optional replacement for the standard cigarette lighter. Moreover, he continues, the current situation is as weird as having a house full of cigarette lighters requiring an adapter to connect electric devices: wouldn’t it be more logical, he postulates, to have standard sockets requiring an adapter to have a cigarette lighter?

I think he has a valid point, even though the idea of a standard mains socket in a car doesn’t make much sense. Cars use batteries, and batteries provide direct current (DC). Mains power is alternate current (AC.) While there are indeed devices called inverters that serve such purpose, they are bulky and usually inefficient. Furthermore, converting 12 VDC to the European 220-240 VAC is even more complicated than reaching the North American 125 VAC mains voltage, which results in even bulkier inverters. To complicate the matter, most units are only able to provide a handful of Watts. Forget about running your iron or vacuum cleaner off one of them.

However, as I was saying, he has a point indeed. Car makers should at least offer customers the possibility of choosing between the standard cigarette lighter, which can be fitted with a USB converter, and the other way around. After all, such converters can be bought for a few euros or dollars.

I personally purchased a 7-euro “iPhone power kit” at a Chinese store, and it came with a mains to USB adapter, a cigarette lighter to USB adapter, and a USB to iPod/iPhone dock cable. Having a standard USB port (minus the data wires, of course) proves quite invaluable, as most new GPS units and phones can be charged via USB. Indeed, the European Union mandated that all phones be chargeable over USB starting in 2012, effectively paving the way to units packaged without a charger.

The solder-savvy among you might enjoy building a cigarette lighter to USB adapter yourselves: all you need is a cigarette lighter shell, a 78L05 linear regulator, a female USB-A socket, possibly a diode (for safety) and a capacitor (for stabilization), and some spare time. I’m not going to provide a schematic as it’s extremely simple. You may want to add a cute LED (with an appropriate resistor of course), keeping in mind that your source is 12 VDC. Better keep that Ohm’s law handy, eh? Note that cigarette lighter ports can provide about 10 A.

As a final thought, I have to say that I haven’t seen anyone using a cigarette lighter in a car in a long while. Most smokers I know use a regular Bic-like lighter even while driving. So yes, bring the USB ports!