Today I went out and played an augmented reality game while walking through a large street fair. I had three things with me: my phone, my water bottle, and my Anker PowerCore+ 20100. I frequently have this combination of items with me, and I generally find it annoying to carry a battery in my pocket, even if it’s a smaller one.
While standing around discussing the fact that we had all run out of water from our respective water bottles, someone thought I had plugged my USB charging cable into my water bottle. We thought it was amusing, but then realized that it would be pretty awesome if I had the ability to do just that.
I’ve come up with several ideas for ways to make the battery + water bottle experience better:
- A water bottle that had a battery built into its cap. Unfortunately this would require me to like the specific water bottle, which I’m somewhat picky about.
- A water bottle mouth insert or lid that has a battery, for instance an alternative Nalgene lid that’s a battery. That way I can use it with whatever custom water bottle I have, as long as it’s the right model.
- A cozy that fits around the water bottle and would let me insert an existing external battery and join the two for easy carrying. This would work well if I had a battery that was of the right size and shape that it wouldn’t tip the water bottle over.
- A battery embedded in a stretchable ring that could fit around whatever water bottle I wanted to use.
I like ideas 3 and 4 the best because they let me pick and choose both the water bottle and battery variety that I like, though I feel like 4 might make for a generally nicer experience given that most of existing batteries are not in shapes that would fit well around a cylindrical object.
What do people think?
They even added a bluetooth speaker to one up your idea. 
If they are wearing some solar panels on their backs. 