I once set fire to a Volvo tractor unit after plugging in a 24 volt kettle, the loom caught fire. Luckily I was able to put the fire out myself, I never owned up to the reason for the fire but since it was well over 20 years ago I apologise to the guy at Volvo Trucks Exeter that had to come out at 0300 in the morning. Thereafter I powered the kettle straight off the batteries.
Providing you don't overload the circuit (with a kettle for example) you should be ok charging phones and running a sat nav.
for the same sort of reason I wired my dashtop blower/heater into the ignition wiring plus fitted an inline fuse.
as when I used the fitted cigerette plug into the socket for it, it got very hot, must have been all that ash/tar/&crap inthe socket I spose.
it works better/hotter/faster fan speed now...plus cant drain the battery if left on without engine running...
another plus is my socket is vaccant for other stuff now...
got mine from aldi, 3 lighter sockets and a usb for a fiver![]()
is there a limit what you can actually use despite how many holes its got ?
nope, its just that cig lighters were designed to draw a high current for a couple of minutes, not for ages and ages, I had one of those heaters in an old motor, and it did the same thing when plugged in.
they were never designed for the use we put them to thesedays, new cars quite often come with an "accessory" socket as well as/instead of a cig lighter, same thing, but usually marked up with a lower current rating for continuous use.