Adding an SD Card via a Micro USB on a Kindle
If you're thinking about using the micro USB port on your Kindle tablet to add an external SD card, think again. The micro USB port on the Kindle Fire or Kindle Fire HD doesn't support SD card readers, or any other type of USB devices. The only thing you can use the port for is to connect the tablet to your computer or to a wall charger. If you need more storage space, consider using Amazon's free cloud storage or purchasing a portable Wi-Fi flash drive.
All Kindle tablets come with free cloud storage on Amazon.com's website. You can save your files and media to the cloud, and then download them to the tablet as you need them. If you need access to your files and media all the time, even when you can't access the Internet, consider using a Wi-Fi enabled flash drive. Many of these drives, commonly called Wi drives, come with apps you can install on your Kindle for easy integration with the tablet. The Wi drives are portable, and you can use them even when you don't have access to a Wi-Fi network.