If that thing goes seriously wrong it could be an impressive incendiary device.

I would want that to be in it's own separate brick outhouse or on a concrete pad twenty feet from anything that should not be sprayed with fire.

See this video of taking apart a USB power pack that runs on hydrogen.

https://www.youtube.com/watch?v=y48wCuC3KcA

Lavo seems to be claiming that one of their devices will last 30 years, which is better than a flooded lead acid battery system, if that is actually true.