Mophie iPhone SE Battery Case
There is already a Mophie iPhone SE battery case that allows you to add 100% more power to your iPhone SE. This was originally for the iPhone 5s and iPhone 5, so there are a lot of colors and styles to choose from.
There is a rechargeable 1,700 mAh battery inside that you charge up with a Micro USB cable. You may need a headphone extension with some pairs of headphones, but if you use the ones that come with your iPhone SE you should be fine.
You can check out additional options on the Mophie website where you'll find more colors and battery capacities. One thing we don;t know for sure is if you'll get the option to sync while using this case or if Mophie will need to offer an updated version so that you can use this.
$19.99 at Amazon