Topics worth your time: how Chargerless builds ultra-low-power wearables that don’t need to be charged, a counterpoint to the idea that hardware takes big teams and bigger budgets, putting datacenter land use in context, and more.
Interesting Video: Renegade Hardware Founders
A typical operating philosophy in engineering programs, whether at a large enterprise or a venture-backed startup with ample capital, is to hire more people as the default response to a problem. This is traditionally true in consumer hardware where a rule of thumb may be a minimum of 70–75 people across mechanical, electrical, firmware, supply chain, and more to get a first product out the door (think Nest or the infamous Humane Ai Pin, though this also depends on BOM count and product complexity). The same philosophy is at play as more companies scale factories (see Hadrian’s $1.37B Series D), with the commitment extending beyond hiring to equipment and production capacity. Large ambitions come with larger budgets, and an appetite to try anything and everything.
Leon’s recent conversation with Andy Kong of Chargerless shows the other end of the spectrum — one that feels more like a thought exercise in going 0 → 1 and finding out how far you can push small teams, or even a single founder. For context, Chargerless is a health-tracking wearable that averages ~7 µW on a sub-10 mAh battery, in a new class of ultra-low power wearable trackers. Same core functionality as devices like WHOOP and Oura, minus the charger.
Some of what stood out from the full conversation:
- Product architecture. The wearable consists of a flex PCB, folded three times, with a monocrystalline silicon solar panel on one side and a sub-10 mAh battery on the other. Boards arrive pre-populated with everything but those two components, since the battery can’t be reflowed and the panel is too delicate; both are attached by hand. It’s then potted for waterproofing, set in a machined case, and cast in clear optical epoxy.
- Supplier relationships are a moat. Part of why the Oura Ring 5 is twice as thin as its predecessor comes down to a battery manufacturer exclusively licensing Oura a new generation of flat ring batteries, leverage that comes only from order volumes large enough to shape a supplier’s roadmap. As he puts it, to work in an industry is to know all the players in it and to know all the developments in the upcoming future of it.
- LLMs are good at bring-up, bad at debugging. One way to bypass that is to close the loop with a DUT on the bench. His setup uses a Jira-style board where new firmware/app features are dispatched to its agents, then tested directly against a DUT and phone connected to the machine. New firmware or app changes are tested in vitro before anything reaches a shipped device.
Lots more interesting details in the full video on solar architectures, sensor sampling rates, how devices use far less power than they did even 5-10 years ago, and what the future of wearables might look like.
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Interesting Chart: Data Center Land Use
A contrarian perspective from Per Aspera on the data center buildout.
Manufacturing & Startup News
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- Prime Minute emerged from stealth with $15M in pre-seed funding to develop systems that fight wildfires from the air, with prototype evaluations planned in Colorado later this year.