Why is the iPhone battery so weak?

You have to charge it up all the time so why haven't they got a battery that can last at least a few days?

They do but it cost way more then you can afford. Maybe a couple hundreds through a couple of thousand dollars. Also Li-on battery are the most practical battery right now. I guess you can buy a battery pack.

  • Why is the battery on my Iphone 5 weak and half of the screen has a blue tint? The battery doesn't even last a 1 day! And i'm not actively using it either. After holding the cell between my shoulder and ear for half an hour the right part of screen has a dark blue tint and it doesn't go away. WTF
  • Why do I feel sleepy and weak? And my temperature changed from cold to hot? When I was sleeping last night I switched on my AC next to my bed, and first I felt cold then hot… I was wearing long trousers but short sleeved shirt. I'm at school now and its difficult for me to walk I feel so weak! This morning I didn't feel like eating as well. I didn't finish all my breakfast just left a bit of cereal on my bowl. Now I don't feel so good, feeling dizzy a bit, I was using my iPhone before going to bed, got a bit of sore throat and cough too?!
  • Why battery percentage indicator in iphone is not showing accurate battery? Let its being charged, let it reached 97 percent, it will still showing charging, but if i off/on it, it will show 100 percent, and it shuts off when it reaches 4 percent, please tell what's problem? and as above i said, if i go to "usage" it will show time charged last time:0 mins standby:0mins but at top right its 99percent and is showing charging?
  • My iPhone suddenly has weak Wi-Fi signal strength? This has been going on for about a week now and it happened suddenly. My 3GS suddenly has terrible Wi-Fi signal strength, meaning that if I'm in my room now, I can't get Wi-Fi while sitting on my bed. I have to be on the same floor basically as my router. Is there something I can do? Is there dust blocking something? Tips please?