Steve, wouldn't it have just been easier to charge those headlamp's batteries via the USB port as intended..?
As an apprentice, I worked with pal Kevin who's first car was an 11 year old Triumph Spitfire. (back in the day when sportscars were actually an insurable option for recently qualified drivers). Kev's Spit was in a local garage for some electrical tinkering so we went to pick it up after work. Mechanic gave him the keys and we went to clamber in. Kev turned the key and, nothing... so he climbed out and went to look for the Mechanic, leaving the ignition on, presumably. I'm sat in the passenger seat when suddenly smoke started pouring, and mean gushing, from behind the dash. Quickly followed by flames. In seconds, the Spitfire's cramped cockpit was full of choking smoke - so I bailed pronto. Looking around for a fire extinguisher I couldn't see one, so I ran to the office hoping to find someone. Office was deserted, so I headed for the workshop, yelling FIRE! Couldn't have been more than a minute or two before the three of us got back to the Spit, by which time the dash and the front of the headliner was well ablaze and the flames were threatening to set the fibreglass hardtop alight. Mechanic did manage to put out the fire with an extinguisher - but sadly the Spit was declared a write-off. That episode always made me aware of how quickly any car's electrical fire can get out of hand. And since then I've always made sure to carry an extinguisher in my car.
