[rationalist]

Vacuum chamber?

[dmoy]

No doesn't appear so. Seems to be just in open air. They've got a kickstarter done for one that does 6+ hours

Guess it's cnc milled, maybe that's part of it. Increase mass of the thing? Idk

[dmonitor]

he is also using development boards wired together rather than a custom pcb. there's a good chance the choice of passive components, removal of unneeded components, and better optimized power converters can improve the design.