Swap an iPhone 4 battery

Every iPhone 4 still running today has a dead or dying battery. The phone came out in 2010. Lithium batteries wear down whether you use them or not, so after this many years there are simply no good original ones left. If you want to actually use an iPhone 4, a new battery is step one. The good news: the iPhone 4 is one of the easier iPhones to open. The battery sits right under the back glass. But there is a catch at the very first screw. Apple used pentalobe screws on the bottom edge. Pentalobe is a special five-point star shape that a normal screwdriver will not grip. This was Apple's way of keeping people out. You need a pentalobe bit, which is cheap and comes in most repair kits. Search for an iPhone 4 pentalobe screwdriver. Once those two bottom screws are out, the back glass slides off and the battery is right there. The battery is held down with a strip of sticky adhesive and one small connector. Peel the adhesive slowly and lift the old cell out. Never bend, stab, or force a lithium battery while removing it. If the old battery looks puffy or swollen, treat it as a hazard, keep it away from heat, and recycle it at a proper drop-off rather than the bin. Buy a replacement made for the iPhone 4, and make sure it matches your exact model, since the iPhone 4 and iPhone 4S use different parts inside. Search for an iPhone 4 replacement battery kit, as many come with the tools you need. A fair warning: even a brand-new aftermarket battery for such an old phone may not hold charge like a phone did when new. Set your hopes for a working retro phone, not an all-day one. Check this phone's spec sheet in the library to be sure you have the 4 and not the 4S.