Why is the battery in the flashlight not charging?
I place the flashlight on the window with sun and then whenever I try and use the flashlight, it only stays bright for a few minutes, then the battery dies.
Check for corrosion on the battery contacts. If corrosion is on the battery contacts and preventing the battery from supplying power to your device, you need to clean the corrosion off. You can do this by applying a small dab of vinegar on an old toothbrush and gently rub the contact until the corrosion is removed. If this does not solve your problem check out Nokero N400 Troubleshooting