Q: Battery problem

Hi Coeli isle,
 

Thanks for visiting Apple Support Communities.
 

If your iPhone always shows a low battery, you may want to review About the battery usage on your iPhone, iPad, and iPod touch and Charge your iPhone, iPad, and iPod touch for more information and troubleshooting steps. 
 

You can start with these steps from the "Get Help" section of Charge your iPhone,...
 

If your device won’t charge or charges slowly

If you have very low battery and plug into power, a black screen or one with a red battery might appear for a few minutes. Let your device charge for a half hour. If it still won't charge, follow these steps:

1. Check your charging cable and USB adapter for signs of damage*, like breakage or bent prongs. Don't use damaged accessories.
   
2. Remove any debris from the charging port on the bottom of your device, then firmly plug your charging cable into your device. If the charging port is damaged, your device probably needs service.
   
3. For a wall power outlet, check for firm connections between your charging cable, USB wall adapter, and wall outlet, or try a different outlet. For a computer, check that it's on and not in sleep mode, then try each USB port on the computer.
4. Restart your iOS device. If your device won’t power on or still won't charge, learn what to do.

*If you're unsure about whether an accessory is damaged, take it to an Apple Retail Store or Apple Authorized Service Provider for evaluation, or contact Apple Support.

Best Regards.