Bug: Battery stops charging for no apparent reason

[Guest icornish]

[Edited by Site Admin, thanks for the submission frillyknickers!]

SYMPTOM:

I experienced this a few times now.

I plug my phone into the charger, then plug the charger into the socket, then make sure the little charging icon is shown. I go away. When I come back (even a few minutes later), it's taken itself off charge, and the battery is dying.

RESOLUTION:

Turn the phone off, and then re-do the whole charging thing. You can turn the phone on as soon as it say's its charging.

[Guest benzo]

I've had this problem.

I found that when it was plugged in, but not charging, I very high pitch noise was emitted from the charger. When I restarted my phone, and plugged in the charger again, the noise went away.

On another note, I have been electrocuted by the charger after I unplugged it! It discharged the remaining current into my hand! Very painful!

[Guest budda]

I've just had this same problem. Although here I had no strange noises or electricution.

I turned off the phone and back on and it recognised as being connected to the mains - I presume it is now charging although, for example, there is no animated indication that the battery is getting topped up. :?

[Guest HelloDave]

I've electrocuted myself with the charger before - not good! If you listen to the charger when you unplug it the pitch of the noise it makes gets higher and higher, as if it's going to explode, and then it eventually goes quiet. I'm not an expert on switching power supplies but I think the noise it makes is because it transforms the AC current to a much higher frequency than mains (50Hz) so that a smaller transformer can be used in the power conversion, which probably explains the high pitched noise (2KHz ish?)- most linear PSU transformers at 50Hz make a low buzz. Having said that my switching laptop PSU doesn't make a high pitched whine...strange. The electrocution is probably because of a badly designed PSU - when you unplug it there's still some stored energy in the capacitors which has to go somewhere; normally it just drains slowly away (probably via losses in the transformer, hence the rising pitch) but if you touch the pins on the plug it goes into your hand instead. It happened to me on the train - quite embarrasing when I screamed in pain :D !

It seems the charger only makes a noise when the phone is in the cradle but not charging (normally becuase the battery is full) so perhaps it is to do with the current drawn from the PSU?

[Guest Bacon]

The electruction will be due to a poorly designed transformer. Basically the coils in the transformer are acting as bigf inductors, whick can give a hell of a kick. Should realy have damping capacitors in there.

As for the high pitched noise - that will be the transformer rattling in its mouts at 50 Hz (mains frequqncy) - it might sound higher pitched for any of several raesons.

[Guest HelloDave]

Well my laptop PSU makes a slight squeaky noise but nothing compared to the SPV charger. Guess it's just crap design then! I haven't experimented to see if it gives me shocks though! :D

As for the high pitched noise - that will be the transformer rattling in its mouts at 50 Hz (mains frequqncy)

Bacon: correct me if i'm wrong here but there's no way that high pitched noise would be due to 50Hz mains! It's gotta be at least 1-2KHz, and why would the noise depend on current draw - the transformer would rattle all the time.

[Guest awarner [MVP]]

Bacon could be part right, 50hz can rattle due to the ac wave form, have you ever heard a worn out 6ft fluorescent fitting they can be quite high pitched and bloody irritating.

but if the noise is too high piched (mine does not do it) it is more than likely a component not up to spec. As I don't have a spare I'm not taking mine apart to find out, other wise I could tell you.

As it's made in China it's anyones guess on the build quality :D

[Guest HelloDave]

I know what you mean about the light fittings but trust me, the charger is a higher pitch than that! I thought it was due to the transformer because switching PSUs use a much higher frequency AC - I don't think the transformer actually runs at 50Hz at all; the mains frequency is stepped up before it gets to it. It only seems to make a noise when the SPV is actually drawing current from it.

[Guest daskew]

If you look at the description on the charger, that will give you a clue about the whistle... it is a switched mode psu and is quite probably oscillating at about 1.5kHz. The rising whistle when removed from the plug will be the resevoir capacitor discharging. Voltage drops, frequency rises... Any form of shock is a fault, send it back NOW!!!!

Cheers, Dave A