My sister had been used iPhone 4 for almost 3 years and for about 6 months ago her iPhone’s battery was easily dropped. That was a second time and then she asked me whether I can repair it or not. I turns in to this video for you as a reference if you choose wanna repair it by your self.
To find an iPhone 4s battery replacement kit, I simply searched eBay for “iPhone 4S replacement battery.” A number of top-rated sellers were offering that product, along with a mini-tool kit, for $8-$10. I chose one priced at $7.99 shipped; it arrived on my doorstep five days later.
Next you can have a look into YouTube, searched for “replace iPhone 4S battery,” and watched a couple how-to videos before even picking up a screwdriver.
One especially good pick: This how-to DirectFix , which is also embedded below. I wanted to learn the procedure as well as I could before getting started.