ManavtheiPhoneuser wrote:
My iPhone is more than an year old already so my warranty period is already over. You’re right in what you’re saying as that’s the most practical thing but I have seen in videos and read in articles that the 8plus gives you about 40-50 mins of more battery especially at the end of the day. I have seen battery tests where the 7 plus battery is as low as 1% and the 8 plus’s battery is between 20-25%. So I was really impressed and I thought of a possibility of putting an 8 plus battery in my 7 plus. I think the connections will be all the same except the lack of wireless charging receiver in my 7 plus.
If you're hearing anything about an iPhone 8 lasting longer, it's not because the battery has more capacity. The iPhone 7 Plus comes with a 2900 mAh battery, while the 8 Plus comes with a lower capacity 2691 mAh battery. If there's anything that would help with runtime it would be more advanced power management on the 8 Plus. It would be with the electronics doing more to efficiently reduce power use than simply providing a larger battery. If you could manage to get it to work (and the iPhone 7 Plus battery management probably wouldn't handle it well). The battery management system is designed to use a specific OEM battery, and going smaller isn't going to improve runtime even if it could work.
The iPhone 8 Plus is actually packed tighter than the iPhone 7 Plus, so the battery is smaller. I'm pretty sure it has to do with the glass back and the wireless charging system taking up more space, so they shrunk the battery a bit. The batteries are also shaped to fit in specific spaces.