A couple of days ago I tried to start my car with the mobile phone charger plugged into the cigar lighter socket.
It seemed the starter circuit was isolated, not even the click of the solenoid going in.
Removed the charger 7 all OK. Reploaced the charger still all OK.
Is this in order?
If so how is the starter isolated ?
I have tried it several times since with trhe same result.
All suggestionsn gladly received.
|
I think it maybe the switchmode DC to DC converter in the charger generating noise in your car's wiring, this noise is interfering with the immobiliser in some way and stopping it from cranking.
Is it a cheap and chearful one from the far east or an OEM for your phone? Try borrowing a different make of charger to see if there is any difference.
|
Thank you ianjoh. Being a mechanical type I do not understand your explantion.
What does a DCtoDC converter do ?
Presumably the noise you refer to is an electronic noise.
The phone is a Nokia given to me about 5 years ago by a friends daughter because it was not "cool" enough, but I have a better one for everyday use.
You could be right about cheap & cheerful from the far east as it came from Tescos.
Thanks again for the gen
|
The DC to DC convertor reduces the cars 12 volts down to probably 5 volts that the phone can handle. It does this by "chopping" the 12 volts at high frequency to produce an averaged lower voltage (still with me!). This chopping can produce all sorts of electrical noise in a poorly designed circuit.
I suspect this is your problem.
Regards
|
Thank you ianjoh, chrystal clear even I could understand it. In short its a sort of DC transformer.
I worked on the design of transformers and switchgear (132 kV & 5000 amps) for 40 years before I retired so I knew you could not transform DC.
By poorly designed circuit I assume are referring to the charger, surely not the car.
At least I hope so !!
|
Its a bit of both. Ideally the car should be immune from interference, but they never completely are.
As far as transforming DC, you're right, it can't be done with a transformer. However chop it using a transistor as a switch and you've got an AC signal that can be run through a transformer. The higher frequency its chopped at the smaller the transformer, however the more expensive the transistor required for the job.
|
Thank you for the info Spikeyhead
When I was working on the cross-channel power link bbetween the UK & Frence it was found that the AC current under the Channel ( La Manche to be PC ) interferred with the passing ships navigation systems etc, so it had to be rectified both ends and then turned back into AC at both other ends.
I reckon it would be a sizeable transistor to cope with that lot.
|
|
one hell of a anti theft device, perhaps you should market it/sell it on e bay (i would like 10% of any sales due to me coming up with the idea) Regards TB
|
OK Topbloke it's a deal
Just let me know when you have finished the design & worked out a price
|
I t seemed the starter circuit was isolated, not even the click of the solenoid going in. Removed the charger all OK. Replaced the charger still all OK.
That sounds to me like a simple problem with the starting circuit, the phone charger might just be a coincidental red herring.
The contacts inside the ignition switch on my 97 Escort are wearing out, when I turn the key to the first and second positions the radio and then all the warning lights come on as normal, but when I turn it to start the engine I have to apply pressure to the key in towards the barrel to make the starter operate. Unless I do this I don't even get a solenoid click either. Could yours be suffering the beginnings of the same problem?
Hell of an anti-theft device
The ignition switch wear works for that too, if I'm out in my truck and someone back at the yard needs to move my car I invariably get a phone call - "How do you switch the immobiliser off on your car, we can't start it"
Thread drift alert - A question for the electrical engineers: how does my cheap Tesco mobile charger know whether it's plugged in to my 12v car or my 24v lorry? My phone charges quite happily in either vehicle.
Dave TD.
|
how does my cheap Tesco mobile charger know whether it's plugged in to my 12v car or my 24v lorry?
It probably uses something like a power transistor that accepts an input voltage between 'x' & 'y' and then gives a regulated output of 'z' volts.
|
