Wireless charging is often billed as a more convenient way to charge your phone, but that's only true if you don't want to use it at the same time. Then, a good old-fashioned cable actually makes more sense. TinyJuice could make wireless charging even more handy, though. It's a small battery with wireless charging built in. That part isn't new, but it also sticks to the back of your phone and includes a finger loop. That part is new.
Smartphones had a brief flirtation with wireless charging a few years ago, but the trend died off as premium devices shifted to metal bodies. Now that glass is all the rage, everyone is doing wireless charging again. Apple, Google, Samsung, LG, and a raft of others include wireless charging coils in their phones that operate on the Qi standard. That means there are uncountable Qi pads out there that will work with any modern smartphone with wireless charging.
TinyJuice is a 3,000mAh battery, which isn't huge. It's enough to give you a single charge on most phones, or at least most of a charge. There are bigger batteries you can lug around, but this one sticks to the back of your phone via nanosuction. The adhesive side of the battery has a material that acts like thousands of tiny suction cups. Press it to a smooth surface like the glass back of a phone, and it'll stick. You can pry it off and use it as many times as you want. I've used devices with similar materials, and they do work well. Although, they seem to pick up dust if not kept clean.
When TinyJuice is suctioned on the back of your phone, it'll charge wirelessly at 5W. That's the base Qi charge rate. Some wired pads can do 7.5, 10, or even 15W, but those coils take up more space. TinyJuice is not exactly tiny, but it's compact enough that you can use your phone with it attached. It's 105g, whereas most phones are around 160-190g. The battery charges over microUSB—sadly, there's no USB Type-C. For devices that don't have wireless charging, there's a regular USB port for wired charging.
As phones have gotten bigger, many people have turned to ring and loop attachments to make them easier to hold. In a clever twist, there's a ring on the back of the TinyJuice. That helps you hold onto the phone, and it can act as a stand if you want to watch video while charging.
TinyJuice still has almost a week left in its Kickstarter, and it's well past the initial goal. A single charger will run you about $25 with an estimated delivery window of January 2019.