iPhone 4

Fourth generation iPhone. Repair is straightforward, but the front glass and LCD must be replaced as a unit. GSM / 8, 16, or 32 GB capacity / Model A1332 / Black and White.

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Polarity of the Battery contacts?

I have an iPhone 4 here, that does not charge anymore through USB (neither is it recognized in iTunes, tried diff. Macs, PCs, cables).

While narrowing down the problem, the battery went empty.

I took the battery out of the iPhone in order to (re-)charge it.

Therefore I want to ask, which of the 4 connectors of the battery are used for charging and to which pins the positive and to which the negative current goes.

Thanks for your help!

Answer this question I have this problem too

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Hi there MrGreen I'd be very concerned about any attempts to charge my iPhone battery by applying any charge to the pins directly. I would either attempt to get a wall charger and continue to try to work on the issue of why it is not charging through the iPhone or I would go ahead and just replace the battery with a new one. Those batteries do have a nasty side to them and do not like to really be messed with. Do a search and check out the exploding iphones due to shortened pins. But anyhow you might consider adapting the circuit as shown here for a charger meant for iPhone 3g/3gs but may be adaptable. http://tzywen.com/modules.php?name=News&... and http://www.instructables.com/id/How-to-m... this should also explain more about the voltage differences between the pins. Just my 2 cents and please be careful and best of luck to you.....

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Hiya OldTurkey,

Thank you for your hints and advise! We have a different setup in the links you posted though. As the iPhone4 battery is not soldered to the board, but removable (it has w. a plug/connector to connect to the board), I want to charge the Battery that I already took OUT of the phone :)

I GUESS (!) I could simply give it +5V to pin 4 and GND to pin 2 - that's where I measured the ~4V the battery provides to the phone.

As I am an amateur in hardware-issues and guessing is not usually how I proceed w. things, I am looking for experienced advise here.

Sorry if I did not make myself clear enough in the original post.

Thank you! :)

by MrGreen

Oh I see, my oversight. I guess you are looking at something like an external charger. It seems that once more Apple is shrouded in secrecy, can't seem to get the info that you need anywhere. But since the phone itself provides the resistance that is required for the charging, it be using less than 5 volts across the battery. I would start of with something a little smaller like 3V just to make sure. I know that the USB supplies 5 volt but the charging circuitry lowers it through the resistors. That is where some of the circuitry should help you out to determine your voltages to the pins. Best of luck to you and be careful and let us know how it went....

by oldturkey03

Hi oldturkey?

did you ever find the pin outs for the iphone four battery? im in the same boat!



by mark duyvesteyn

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Try holding the battery with the terminals up. The top most terminal ( Outer) is the negative. The terminal at the bottom ( Outer) is the Positive. I just used an ordinary battery charger to charge the battery without using the Iphone. All you do is to cut which ever pin your charger has and connect the conductors to the terminal. Usually the red goes to the positive and black to the negative terminal. Some times different colors are used for the conductor. The principle remains the same. the dark colored conductor is negative and the other light colored is Positive. If they are three, the third one is ground. Just ignore it, or connect it to the middle pin on your battery. I hope this helps.

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The best way would be to use a charger for Li-ion Polimer batteries at 3.7V (For example a camera battery or cell phone charger will have the four contacts) and determine the +ve, -ve and I believe the other pins are to control the charge. By doing it this way there is little chance of it overcharging the battery and possibly damaging it.

If you do not have one of these chargers and have a bit of an electronics inclination you can even use an old cell phone that you are ready to recycle making sure it provides the four pin lay out for a 3.7V battery. You may have to solder a couple of wires or use alligator clips or some way of connecting the wires from the old cell to the battery ( ensuring proper polarity).

I have done this before and it works.

Hope this helps


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1. Remove the black tape at the flex side to open the small regulatotor chip. 2. Bend dhe chip away carefully to reveal 2 poles cover in aluminium foil. 3. Use a dual pin universal charger with the pins connected to the metal base of each pole. No need to worry about the polarity when using the charger.

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I would not recommend charging a lithium battery in that manor. You could get away with that when dealing with any other type of battery such as nicad or metal hyd. But a lithium require varying charge rates at different points and can violently erupt or burn. The phone is controlling the charge. Be warned. Find another device or battery to test with please.

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One of the many iphone 4's I bought off Ebay to repair exhibited this symptom,(no connect to charger, no connect to computer and thus itunes). So when the battery died my only option was to swap out a charged battery from one of the others. while I was never able to repair this particular phone, you might consider, if you have only the one charging cord, that the cord might be the culpret, and not the phone at all. Try the cord on a different iphone.

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MrGreen will be eternally grateful.

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