OBSOLETE - Battery Bulge Inspection

Introduction

IMPORTANT: AS OF ~7/2/2023 (archived years prior), THIS GUIDE IS NO LONGER UPDATED BY THE AUTHOR. This guide was made around the iPhone 4 which hasn't worked on US carriers for at least 10+ years due to a lack of 4G or VoLTE. This guide may apply to other devices, but they often have such stark differences it is unlikely this approach will work for you. These are also prone to repair cost issue as parts can be as much as the entire phone.

Are you concerned your iPhone 4 may have a bulged battery after many years of use? Here are some basic ways you can see, short of opening the phone.

Step 1 Check for power on a iPod dock

OBSOLETE - Battery Bulge Inspection, Check for power on a iPod dock: step 1, image 1 of 2

OBSOLETE - Battery Bulge Inspection, Check for power on a iPod dock: step 1, image 2 of 2

Plug the iPhone into a compatible iPod dock or charger with 30-pin cable. If you do not find the phone turns on in a reasonable amount of time, you may want to supervise the phone. If the phone still has problems, further inspection is required.
If your phone feels "bubbled", the battery may explode. Stop the tests and replace the battery. Continuing beyond this point runs the risk of the phone exploding.

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Step 2 Try resetting your phone

OBSOLETE - Battery Bulge Inspection, Try resetting your phone: step 2, image 1 of 1

Try to reset the phone. Do this by holding the power and home buttons together for around 30 seconds.

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Step 3 Check with a computer

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OBSOLETE - Battery Bulge Inspection, Check with a computer: step 3, image 3 of 3

Plug the phone into a computer and see how it responds. If the phone works on a computer but not a charger the battery is shot. At this point, it's a matter of checking if the phone has a bulged battery or not.

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Step 4 The table test

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OBSOLETE - Battery Bulge Inspection, The table test: step 4, image 2 of 2

Put the phone on a flat table. Check if the display has a bump. If the display has a bump, it's safe to assume you may need a new battery. The battery is on the right side of the phone, so focus on this side of the phone. You may not notice this if you do not know what to look for. You need a keen eye to notice this unless it is obvious.
If you still are not sure, spin the phone on a table to see how bulged it is. If the phone spins without stopping quickly, the battery is bulged. Light bulges may cause the phone to be unstable, but it is not as likely to spin or show as a bulge on the LCD.

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Step 5 Spin the phone

Put the phone on a table and see if it spins. If it does, the battery is bulged.
It will not spin in every single case of a bulge, but larger bulges will spin.

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Step 6 Press the right side to check for a bump

OBSOLETE - Battery Bulge Inspection, Press the right side to check for a bump: step 6, image 1 of 1

This should be simple. Press down on the LCD on the right side of the phone. If the phone feels like it has a soft area, the phone needs to be taken apart for inspection. Phones that do not have a bulge on the battery side of the phone are probably fine. However, it may still be a good idea to open the phone to be sure.
Do not use too much pressure for this. Using too much pressure can damage the LCD. If you break the display, it usually ends up costing more then a replacement display. Breaking it is basically a death sentence to the phone.

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