From the MAKE Flickr pool

In a bind, Nick found a way to power his phone with the only parts available –

My phone went dead in Philly. It’s an old enough phone that none of k-mart, radioshack, or a dozen dollar stores sold a charger for it. Finally, I found a car charger at a dollar store. I also bought some speaker wire, two nine volts and electrical tape. For less than $5, I could charge my phone.

Nice – it’s the simple ideas like this that can help the most. Though I’m assuming that lighter adapter is designed to accept 12 volts, handling 6 volts extra probably doesn’t do much harm in a pinch.

Update: In the comments, Steve writes –

Cigar lighter sockets can push out 24V in vehicles with 24V batteries
(big trucks, boats and things) so devices that are designed to be
plugged into them are often labelled as 12V/24V (Google for “cigar 24v”
and you’ll see).

Also, the output you get from the socket is typically very dirty –
rarely 12V, often around 14V as the alternator kicks out more for the
battery charging.

18V wouldn’t kill it, not by a long shot.