Change battery
how to change my battery and will it be the same effectiveness as the one that comes with the phone?
Question marked as
Check -> iPhone model -> go to Settings -> General -> About.
If it is possible to have the battery replaced at Apple, see here:
iPhone Battery Repair & Replacement - Apple Support
If you are going to replace the battery, by Apple or an Apple Authorized Service Providers read this Apple article:
Get your iPhone, iPad, or iPod touch ready for service
Get your iPhone, iPad, or iPod touch ready for service - Apple Support
and will it be the same effectiveness as the one that comes with the phone?
Call 1-800-MY-APPLE or check here for more support and assistance.