Replacing iPhone 4S battery

I really don't understand why people complain about iPhone screen size being too small. Personally I'd rather carry a phone, not iPad. Also it happens that iPhone 4S is one of the best phones Apple ever manufactured, it is robust and take mis-handing, it is stable and never crashes on iOS 7. You cannot say that about previous or later phones. And IMHO the best feature about 4S is that it simply has the correct size!

My unit started showing symptoms of aging. Battery charge time was over 3 hours from 20% capacity to full, which felt like much longer time when my phone was new. I'm using Battery Doctor app to monitor the charging to keep my battery in a good shape, but the fact of life is that batteries wear on usage. It was time for me to replace it.

Going to an authorized Apple service was absolutely ouf of the question. I've always wanted to see what's inside my iPhone! The absolutely best thing is to get the new battery and tools for the service from iFixit.com. They even provide a very nice guide for the replacement job iPhone 4S Battery Replacement. As the obligatory warning part I'll simply say, that there are very small parts inside and provide this pic as proof:

That's set of iPhone screws on an euro 1 cent, which is on top of US quarter. The leftmost two screws are Phillips-head battery connector screws and the rightmost screws are original Apple Pentalobes. This should scare you away from ever attempting to do any of this stuff by yourself. If it doesn't, please read forward!

So, I put in my order and in a couple of weeks the box arrived from USA. The box contained:

• The replacement battery
• Phillips-head screwdriver to remove the battery connector and insert the liberator screws for the back lid
• Pentalobe-head screwdriver to remove the back lid
• Plastic tool for prying the battery loose from the sticky stuff it is fitted into
  

The first task is to remove the back lid. It can be done by removing the two Pentalobe-screws next to the bottom dock connector:

After the screws are removed, the back lid will slide bit upwards, that is away from the dock connector:

After that the lid should be loose and can be removed without applying force to it. It has some tricky plastic tabs on the sides, so please be careful with those. They're the ones actually holding the lid in place. Don't break them.

The guts of the phone look like this:

Next step is to remove the battery. This can be done by disconnecting the battery from the phone and then prying the battery loose from the glue. The battery connector looks like this:

It is mechanically not a tight one. First remove the two Phillips-head screws and the try to disconnect the connector pins by sliding the connector towards the battery, like this:

Warning: when the battery connector is loose, it is absolutely certain that you will remove a pressure connector in the process:

iFixit says "Pay attention to the pressure contact underneath the top screw of the battery connector. This may come loose while prying the battery connector from its socket". I already said: It will come loose! Just don't misplace it. Try to figure out how it was, to get it back in place.

Then pry the battery:

It is held in place by reasonable amount of gooey sticky stuff:

Now you have removed the battery! It is another story of getting it all back.

The battery looks like this:

Batteries from left to right: old backside, new backside, old front side, new front

Not much of a difference with the old and the new one. Based on the LMG 08/2013, my new one is manufactured about a year ago. It had 40% charge when I turned my phone back on, I guess that's ok.

Anyway, to put it back together, put the battery in it's slot and try to figure out how the connector cable goes so that it would be possible to put the connector screws back. Before actually placing the battery contactor, concentrate on the loose pressure connector. It should look like this:

Then put the battery connector and try to put the top screw in so, that it would hold both the battery and pressure connectors in place. Then put the bottom screw in. When done correctly it should look like this:

Then the last step is to put the back lid in, slide it to place and liberate your iPhone with the new Phillips-head screws:

After that you're done. Congratulations on your new battery!

When I first turned my phone back on, it didn't find my SIM-card. I don't know what happened, but everything else worked, except it never asked for my SIM PIN-code, nor ever found any telephone operators. I fixed the issue by shutting the phone, going to airplane mode didn't do the trick. On next power on, it did ask for my SIM PIN-code and found my telco quite soon.

My thanks goes to iFixit for their excellent guide. I simply wanted to do my own to fill in the gaps they left.