iPhone battery drain within 2 weeks

I have an older iPhone (a SEgen 1) and it can drop by at least that much in a few minutes if I am doing something such as updating apps. That's not saying yours should drop that much but you have really not provided us with enough information to analyze this carefully. What model iPhone? Age of device? What are you doing when this happens?

Go to this support page:

Check the iPhone battery health and usage - Apple Support

Read the section: View your battery usage information

On your device go to Settings  > Battery.

What's it doing?

Do you mean in two hours your battery went from say 80% to 75% in charge level? What were you doing on the phone in those two hours? How strong is your cellular connection, which can use a lot of charge, even if the phone isn't being used.

• What model phone
• how long has it been since the phone was new
• are you the original owner, or was it a used phone?