"The solar-powered headphones still have a built-in battery that can power up to 80 hours of playback time. It is this that the Powerfoyle strip charges. Mr Fili says that currently the tech can create one hour's worth of power "from just 20 minutes of English or Swedish summer sunshine"."
A very bold claim, I do wonder if that's with the strip placed optimally facing the sun, and not integrated into a headset.
The idea of a solar jacket to keep a hikers satellite phone topped off sounds more attractive though.
Assume:
* solar panel is about 1.5cm x 20cm = 0.003m^2
* Efficiency = 10%
* solar insulation is 1000W/m^2
Power = 0.3W
In 20 min you gain, 0.3x1/3=0.1Wh of energy.
Now, these random Sony headphones [1] have 30h life with a battery of 3.7V, 1200mAh [2]. This means they consume 3.7*1200m/30 = 0.148Wh per hour.
Seems like claim is roughly in the ballpark.
[1] https://www.amazon.ca/dp/B0863TXGM3 [2] https://www.amazon.ca/dp/B08YQX76B1
It's definitely in the right order of magnitude, this could definitely be doable.
This could make a lot of sense for the student market, where you listen to music/podcasts/whatever between classes and then the headphones get a decent charge when you walk between buildings, walk home, etc.
Nice.
which reminds me that I regularly find old PV pocket calc, with I forgot what kind of oxide they used, still working fine..