Fuses Blowing

[whiskeryron]

I have a 2005 Skoda Fabia estate & I have only recently started to use a Sat/Nav in it. My problem is that the 12v cig connection is not charging the Sat/Nav. I have also tried using the 12v outlet in the boot with the same result. I have checked & changed the 15a fuses in both & by using a portable 12v Heater/ Fanblower I have found that both outlets are working until I disconnect,then as soon as I connect again they have both stopped working. Obviously the fuses keep blowing. Can anyone suggest a solution or is going to mean booking the car into the main dealer again ( the car was recently serviced & M O Td)

[Hymie]

I would take a close look at the device you are plugging into the sockets – my bet would be that there is an intermittent short within the wiring to the device. For a 15A fuse to operate within a short period of time, over 25A (300 Watts @ 12V) will be flowing. Alternatively there may be loose wiring at the back of the socket causing the short – but from what you describe, this would apply to both sockets. Try plugging something else in each socket, preferably lower powered than a heater.

[whiskeryron]

Thanks Hymie, although it is a portable 12 v heater I am only using the cold blower fan as a circuit tester which I would have thought was low wattage/amp.

[Hypognosis]

I vaguely recall something about momentary high current flow when an electric motor receives power but hasn't begun rotation. Western manufacturers add some componentry to flatten out the spike, 'back current' effects and so on.

[Iggle Piggle]

is it both outlets that blow the fuse on disconnection? I had this happen and I found the metal strip down the side of the barrel connector had slipped and was shorting the socket. Has the sat. nav. adapter got a light in the plug? Use this as a checker.

[Hymie]

15A is quite a reasonable value for a 12V cig connection fuse - it requires quite a bit of energy to get a piece of metal to glow red-hot.

But most tech equipment plugged into the outlet will be drawing less than 1A. Well designed adapters will be capable of handling this current in the event of a fault.