Iphone 4s: Shutting off even with a full charge?

I have had my Iphone 4s for maybe a year or less, but it has had a previous owner, my sister. It can have 80% or higher and it will shut down, then when I try to power it back on it has the plug in charger symbol as if it has no battery. However, if I wait, I can power it back on but it will shut down again soon after depending on the moment. Does it require a new battery or just a restore?

Added (1). -new info-
I've done a hard reset and and restore and it still is shutting off on me unless its on a charger. What's even worse now is that the charger isn't working properly.So, basically, I have lost all use of my phone even though it had a high charge last I checked. It's not too important but it does help me ride the bus to school, and my ride is around an hour. I'll just have to read on the bus without my music. *sadface*

I would try restoring it first, but since its used the battery might be gone since you don't know how it was treated before you.

How about taking it to the Apple store?

  • Wi-Fi keeps shutting off automatically on iPhone? I recently purchased an iPhone 4S and ever since I connected it to my Wi-Fi home network it has been disconnecting off of the Wi-Fi and using my 3G. The Wi-Fi works great on my other devices, and I have to keep manually going to settings to connect it. Please tell me what to do to fix this issue and let it stay on the network until I manually disconnect it. 10 POINTS for the correct answer
  • Why is my iPhone 4 always shutting itself off when not on charge? Today I got a new iPhone 4 and for the first hour or so it was working fine. It kept turning itself off whenever it wasn't on the charger but it was already fully charged. I would turn it on then it would just turn straight off. I need help.
  • My iphone keeps shutting off? I have an iphone 3g. The only way it will stay on if its on the charger or if its off the charger it must be playing music to stay on, but as soon as the music stops playing it will turn itself off and then start blinking the apple. The apple will come up and then go away and then come back. This just started happening lastnight, how can i fix it?
  • My Iphone keeps shutting off, but before it shuts off, my screen freezes and there's these lines that show up, they're random? My Iphone keeps shutting off, but before it shuts off, my screen freezes and there's these lines that show up, they're random. Sometimes there's this crackling sound, and sometimes the line move, my mom says its just the phone, but my dad says, its the proccecor and that its overheated, i have an Iphone SE rose gold 64 gb and my iOS is 12.3.1