Sat nav charger appears to have damaged two cars

[Geekman]

I've got an aftermarket charger for my sat nav - I got it about 2 years ago, and other than blowing a fuse on my dad's car a few months ago it's been fine. At the time we didn't even think it was anything to do with the charger as his car was a bit of a shed.

About a week ago I was driving my 2003 XJ6 and I seem to remember I plugged my sat nav into a different cigarette lighter port to the one I normally used. Around that point in time, I got all kinds of electrical issues appearing - when the headlights were turned on the windows wouldn't work, the instrument illumination wouldn't work, the EML came on etc etc

I checked the earths and put a new battery in it but this didn't solve the problem. At the time I thought it may have been caused by me DIY fitting a new heater resistor a few weeks previously - I didn't even consider the charger as the culprit.

So, I took the jag down to a specialist, where it remains still, for diagnosis. As I knew the car would be there for a while, I removed my sat nav and charger and plugged it into my other car (Toyota MR2) so I could use it for work.

Literally the second I plugged it in, the radio cut out, the clock died and the security light started flashing. I tried disconnecting the battery to no avail, so it appears as if it's caused exactly the same problem.

So, what do people think? Is it even possible for a sat nav charger to damage a car? If so, what components do we think may have been damaged?

[FUBAR]

A few years back myself and a number of other TVR owners purchased some cheap Chinese 'TVR stamped' cigarette lighters off eBay. Every one of us had electrical problems following half a dozen fuses blowing the moment the lighter was put in the socket. I presume your charger was made in the same part of the world?

Convinced me not to buy knock off electrical goods

[PhillipM]

There's a lot of those chargers making a lot of electrical noise - I had one so bad that when I plugged it in you could pick the transformer/coil whine up on the radio!

[Geekman]

I just went though every fuse in the MR2 and replaced 4 and it seems fine now. The jag is obviously still at the garage so I'll call them tomorrow and mention about the fuses to see what they say. The ones on the Jag looked fine but who knows?

[vikingaero]

It's not just cheap Chinese chargers. I bought a brand new TomTom Go730 years ago. I plugged the charger into the 12v socket and it started burning and smoking.