Asklemmy

It flopped because it doesn't really work, and most stuff we stick batteries on these days already do a good job of extracting all the energy out of the batteries. It's mostly already built-in.

EEVblog made a few videos on it:

• https://youtu.be/Z-m-7jex88k?si=KhEtCmvGkeyEtj4h
• https://youtu.be/Tl90m2KHbNk?si=0LK6Op_E32w3tMSO
• https://youtu.be/dnXiLBabSTU?si=DufjcVHCvlLSGi5Q

Dead old batteries are dead, if there's almost no energy in them they're done. Best case you might be able to stick them in a remote or an LED candle or whatever. But it's a physical limit: almost dead batteries just can't supply high currents because of internal resistance.

Another way to look at it is those potato batteries: yeah, you can measure a voltage off them. Yeah, you might be able to light up an LED. But you will never be able to power something higher power, not even for a couple seconds. It's physically not able to provide much current.

The wikipedia seems to keep using words like "it claimed to X"

Also

The shipping date for the product has been delayed for various reasons, but photos from the manufacturing process have been made available. As of early May 2016, the company was months overdue to ship to its Indiegogo backers, with some backers accusing Batteroo of running a scam.

TechnologyCatalyst suggested that the device could be useful "if Batteriser was honest about its product", not to prolong battery life but to stabilise voltage over its lifetime.

So I think the other comment is reasonable. Rechargeable batteries (ex. People mention Ikea ones and Eneloop) are pretty good now so people that want it can go for those

Reality happened. The voltage drops because there is jack shit energy remaining and stepping up the voltage does not magically make that battery not almost completely drained.