Hi, i recently brought a navman sat nav which is great works really well etc, however it didn't come with a mains charger, just a car charger luckliy i have managed to fix my car's cigarette socket but i brought a mains charger off ebay anyway.

However when i got this morn and tried it out it makes a high pitched whining noise when plugged in the mains, its not very loud but i was wondering what it could be or if its normal?

opinons gratefully recieved!

hmm mine makes no noise at all when charging...

Sounds as though the tone is higher than the normal hum, though I have had charges in the past that whined.

The charger for my old phone (nokia 6230) makes this sound when the phones not connected or its fully charged.

is pretty high pitch, it seemed to charge ok but i guess i will take it up with the seller, i don't want to break my nice new sat nav!!

Often audio devices need a smoother power supply so its probably not as smooth as it should be - I doubt that it would do any damage though. You could try another psu of the same voltage.

Hi, all i can add to this topic is that one of my mains chargers makes a noise like u describe, it only seems to do it when there is no load on it tho. Maybe yours has a high output that the navman just isnt using up?

That is possible as i had it plugged in with no load and it was making the noise then i tried it in the navman and it still made the noise but i think its fully charged as it's been plugged in to the car on a hour long trip so i guess i will have to discharge it and try it again!

am prob over thinking this the noise sounded pretty loud but that was in a really quiet flat as i was about to leave for uni

Most modern chargers don't use large transformers - these would give a 50Hz hum. The screeching of modern chargers is down to switch mode power supplies running at a couple of kHz. These are usually a lot more stable and have good over voltage protection.
Don't worry.