[Android Software Development] hgmichna:
Samsung Galaxy S III LTE (GT-I9305) charging issues

I just sent the following email to several friends who use this phone, but I am sure the same holds for many different types of phones.

Since this thread still attracts readers, I think it cannot be wrong to wake it up again a little.

If you can use Amazon, a good idea for fast charging is to buy one of the charge-only cables made by portapow. They have no data lines, so don't try to exchange data through them, but they have thick power lines, suitable even for higher currents up to 2.1 A.

My email follows:

One of us users of the Samsung Galaxy S III LTE (GT-I9305) has recently experienced charging problems. She could no longer reliably charge her phone or could hardly charge it at all.

This can have various causes, but by far the most frequent cause is that the charger has gone sour. These chargers are, unfortunately, not built to last. If this is indeed the cause, you will eventually have to get a new, better charger.

Other possible causes are:

* Dirt in the USB (Universal Serial Port) charging socket at the bottom of the phone

Try to clean it by blowing into the hole and cleaning it out with a toothpick. Don't use a metal needle, because that could cause a shortcut. And be careful. These sockets are a bit flimsy and can easily be damaged. You could try to shine a bright light into the socket to see whether there is any dirt.

* The cable could be broken.

* The battery could be finished.

* The phone itself could be broken. This is unlikely.

To find the cause, swap the charger and swap the cable for testing. If everything is good, the phone should charge 5 to 10% in 10 minutes, so you can even go to a phone shop, borrow a strong charger for 10 minutes, and try it out.

Tools - Battery information

There are a few helpful tools. The easiest one gives you information about your battery. Call the number: * # * # 4 6 3 6 # * # *

Easier to remember: * # * # I N F O # * # *

You will get a menu. Tap "Battery information". There will be a line "Battery health:", which should show "Good". If it does not show "Good", your battery is most likely dead or near-dead.

Tools - App "Ampere" by Braintrapp

Another helpful tool is the app, "Ampere" by Braintrapp. It can show you at any time how much electrical current, measured in mA (Milliampere) flows in or out of the battery.

Your charger should provide up to 1,000 mA current. While the phone and particularly its screen is on, the phone itself will consume around 200 to 300 mA of that, so the rest, 700 to 800 mA, should flow into the battery to recharge it.

When the phone is not charged, the app shows you how much current is drawn out of the battery.

Note that the charging current is much lower when the battery is nearly full. This is normal.

Other information

If your charger went bad and you cannot quickly get a new one, you may still be able to charge your phone at least partly and very slowly by powering it down, then letting it charge overnight. Powering down does not make a big difference, because the phone does not use much power anyway while the screen is off, but it helps a little. In the long run you probably need a new charger though.

You can use any charger without damaging anything. You can also connect the USB cable to a computer, but there you will get only up to 500 mA current, so charging will take about two to three times as long.

For fast charging the charger should provide at least 1,000 mA, i.e. 1 A (one Ampere) of current. With weaker chargers the phone will step down the current and will charge more slowly.

If you have to buy a new charger, make sure it provides at least 1,000 mA current. And it may be a good idea to get one in its original packaging, to avoid buying chargers that have been abandoned by their original owners because they have also already failed.

It does not have to be a Samsung charger. In fact, I think that Samsung chargers may be the worst. As long as the micro-USB plug fits your phone, the charger will work.

A stronger charger does not hurt. The phone determines the current, and it will never draw more than 1,000 mA, even if the charger can provide much more. Chargers with 1.5 A and 2.1 A are common and work well. I have a 10 A (10,000 mA) charger at home with 5 charging ports, and all phones charge nicely from that as well.

USB cables are problematic because they are often too thin for fast charging. They will all charge your phone overnight, but long, thin cables may not sustain the required voltage at currents like 1 A, so the charging can be slower. If in doubt, get a short cable and avoid very thin cables.

Smartphones are designed to lower the current when the charger and the cable do not provide the proper voltage of 5 V with a tolerance of plus or minus 0.25 V as defined by the USB standard. Some people maintain that the Samsung Galaxy S III family of phones is particularly picky here and quick in lowering the current when anything is not quite perfect. I cannot check whether this is true, but it seems that with a good charger, a good cable, and a clean micro-USB socket our phones charge quickly, from empty to full in about two and a half hours.