Charging Issues with an Android Phone

Thanks Brian. I don't have any other device to charge through it but the GPS runs OK through the other socket. I have used the double adaptor in the 12v socket in the caravan with a 300 Amp inverter running through it and there are no problems with that.

Kevin

Try itin the other side or even without the adaptor. Some of those adaptors are pretty poorly made, the centre terminal can be very ordinary, and sometimes you need to twist the plug in the socket to get a good connection to the earth as well.

Same problem when I don't use the adaptor at all but put the charger usb plug directly into the 12v socket in my vehicle Brian.
Kevin

That tells us that it is not the adaptor or the socket, so you may need to look at a problem with the cord, possibly loose connections or wire too thin.
Another possibility is that you are overloading the USB device, although I gather that you have been using it successfully for a while, so that may be erroneous advice.

Also check the maximum output of the USB adaptor, you may be drawing too much current when the GPS function is being used.

David, There is a little more to this USB charging than meets the eye.

You may remember that I was having charging problems with my Samsung Galaxy Note 10.1 at Maralinga when charging using a "standard" 12v/USB adaptor with 5v, 2.1A capacity. The on-screen charge indicator icon showed a "red X" indicating that it was charging at a reduced rate. This charge rate was insufficient to maintain the required battery level whilst the tablet was in active operation. There was no problem charging at the full rate when using the authentic Samsung 230v charger from my inverter.

Investigation revealed that a "control" signal is generated by USB chargers and this needed to be of the correct value in order for the tablet to select the higher charging rate. Fortunately the August issue of Silicon Chip magazine published a construction article on "iPod Charger Adaptor" which revealed the need for providing a specific signal voltage on the D+ and D- (pins 1 & 4) of the USB socket in order for the device (iPod, iPhone, Galaxy etc) to recognise the charger as valid before charging occurs. There are in fact six devices listed, each with a differing signal requirement. Just why such a signal is necessary is unclear to me.
The provision of the specific signal voltages is derived from the 5v input by resistor dividers within the USB plug. These voltages and the resistor values are detailed in the Silicon Chip article. Testing the original Samsung mains charger revealed the required 1.2v present at pins 1 & 4 of its USB plug and confirmed the Silicon Chip article.

So………., I inserted the resistors nominated for the Samsung Galaxy Tablet and behold…… charging operates at the full rate with no Red X on the tablet charge indicator. Success, but I may not have found it but for the Silicon Chip article.

I have no idea just why this signal is required. I would have thought that if the device was simply presented with a USB 5v supply of adequate current capacity then charging would proceed at full rate. But it seems not!

Note that the issue applies to not just the Samsung Tablet but to a range of iPod and iPhone models although there is no mention of Apple iPads and I am not suggesting that this issue necessarily applies to Kevin's Galaxy phone. Can anybody throw more light on this subject?

Hi Allan,
Glad to see you again (so to speak). Thanks again also for the shock rubbers I had meant to send you some replacements alas I forgot.

Very interesting observation and research. I have always been miffed to understand why some of these devices say this charger is not supported even when the current supplied should be well and truly enough. That make perfect sense even though it would seem silly for this requirement. It would seem judging by the different requirements for each device that it is simply a matter of trying to ensure you buy the specific adaptors at an inflated rate for each device.

Would be great to find out more on this strange requirement.
Thanks for the interesting input Allan.
David

David,

Here is the table from Silicon Chip showing the D+ and D- values for a variety of devices.



It can be seen that "Charge Requirements" are related to each device. Is it possible that this system is intended to limit the maximum charge current for each particular device? Even so, columns 1 and 5 both have 500mA charge ratings yet have differing D+ and D- voltages. Similarly with columns 3 and 4, which tends to blow my theory.

Kevin's original post indicated that the devices worked OK for some time before becoming unreliable so it is unlikely to be a matter of charger incompatibility. So maybe I am getting Off-Topic?

It is all interesting input Allan. Thanks for your contribution. I think I have eliminated cable and adaptor as a cause. Not sure about the actual usb charger. There could be a quality problem there. More work needed.
Kevin

I have just spent hours searching the Internet on this subject.
My eyes are sore and my head hurts!
I found many references that confirm what I have already posted here but nothing to explain why this current limiting is adopted or necessary.
I was not even able to find where Silicon Chip got the information of the correct various D+ and D- voltages from.

However, I have already solved my problem with the Galaxy Note 10.1 so I no longer have a problem and I will leave it at that. I'm going to rest my head.

Allan, you are a good man. Thank you for your efforts. I am interested in what you have done with your Note 10.1. I would love to own one and if I ever do your experiences could be helpful.
There is a great deal of information on the Internet on Android charging problems but much seems to relate to physical problems with the USB port.
But I now have more reason to think that I have a faulty phone. It was on the charger overnight but has not charged. After I disconnected the charger from the phone the battery charge icon continued to flash. I rebooted and the flashing stopped but the level of charge was lower so it had not charged at all. It is now back on the charger. We will see what happens next. Hopefully all this will help other readers.
Cheers,
Kevin

I have not heard of that phone Andrew but I am not in the market for another new phone. Some of us have to work on limited funds. I have owned 3 ZTE manufactured devices and they have all had to go back for repair or replacement, so I am not a great fan of their products.
Kevin

"Thanks for all the input. I think some of you may have missed the fact that with both devices active and operating from the vehicle battery with the ignition in the accessory position there is no problem. It is only when moving - slowly and at speed."

Have you tried charging the devices with the engine running, but the vehicle not moving? The input voltage to the USB charger will be higher with the engine running, and this may be causing some issues with output voltage. Can you test your socket with a voltmeter?

The cigar socket is delivering 13.9 volts consistently once revs get above idle and this is repeated at both sockets of the 12v double adaptor. The phone charges with the motor running and doesn't start to act up until I am 20 minutes or so down the road. I have not yet developed sufficient dedication to research to sit in the vehicle for that long to see what happens.
Cheers,
Kevin

You may be getting too many volts into the USB charger and it's charging the battery at too high a rate. I had this happen recently with an HP iPaq. What happens is that the device battery starts to overheat and a protective circuit kicks in and stops the charging. I had to wait for the device to cool down until charging started again. It did pop up an error message saying this had happened, but your phone may not have this. Your device may be charging, overheating, charging is shut down, wait a bit for device to cool down, charging starts again, repeat ad infinitum. Also, how old is your phone? It might be that the battery is getting a bit worse for wear and needs replacing.

Another possibility is that you may not be getting enough voltage once the engine has warmed up and the starting battery is fully charged. Some modern systems (I know Toyota does this) keep the voltage at a minimal level to reduce fuel consumption and conserve battery life (starting battery, that is). I have a Galaxy Ace Plus which I have charged at all stages of travelling and had no problems. I also have a small mod to make sure my voltage stays high enough to keep my second battery charged.
Hugh

Thanks Hugh, you have set me thinking. Almost all of the distance on my recent trip where I dad no charging problems the van was on behind so the alternator was driving the three way smart fridge. That suggests too much power might be the problem as someone has already suggested. To take another approach, I suppose I could always bring wires forward from the house battery in the Challenger (mounted just inside the tailgate) so that the phone is charging from a battery and not from an alternator.
Cheers,
Kevin

Hi Darian.

Do you mean the vibrations transmitted through the mount from the vehicle?

Kevin

That was my thought - I doubt that the socket used for data transfer and charging is considered robust to any degree - I've assumed that the manufacturer envisages the phone is laying still somewhere while that plug is inserted. If the phone is wobbling on the window mount while the plug is in there, that might be enough to reshape contacts and produce dodgy connections. I can't recall where now, but I did read a technical text somewhere on this issue, for very light duty sockets and plugs on phones.

An interesting point Darian. Thing is that it happens on smooth road where there is no movement in the phone in it's mount and then doesn't happen more on rough or corrugated roads.
Kevin