Can I instal a iPhone 4S battery in iPhone 4
I know a iPhone 4S battery it's better and bigger then iPhone 4.
What will happend if I instaling a 4S battery in my iPhone 4?
Max Agarkov, the main reason why you can't is that the battery conector is different. the battery for the 4S has two mounting holes, the 4 has one. Also, check on the teardown and see what it says "You probably want to know if you can use this battery in your iPhone 4. Sadly, it appears that the connectors are different shapes, so we'd have to say that it's not likely." from here. Hope this helps, good luck.
You probably wouldn't want to do that. The iPhone power management system was made for that battery and that battery only.