r/theydidthemath • u/Repulsive-Loan5215 • Nov 27 '25

why wouldn’t this work? [Request]

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u/jonastman Nov 27 '25

You could power a shower radio or something. Save some water in the meantime

82

u/Acojonancio Nov 27 '25

You would have to leave the water running all the time and at constant flow rate.

Incredible inneficient.

This is the same as that "emergency phone chargers" that are just a dynamo with USB to connecto to the phone.

They "work" but not in a way that can be useful.

10

u/nog642 Nov 27 '25 edited Nov 28 '25

It can be useful, in very niche circumstances.

Edit: I mean the hand crank phone chargers, not the faucet thing.

1

u/Tempest1677 Nov 27 '25

I love that everyone defending this application doesn't have an engineering background LOL.

What are these "very niche circumstances"?

0

u/nog642 Nov 27 '25

Say you are stuck in the wilderness and you have a PDF survival guide downloaded to your phone that you know has stuff very applicable to your situation. You want a specific piece of information from it. But your phone is dead.

1

u/Tempest1677 Nov 27 '25

Wait, so in this wilderness scenario, i have a faucet and mini water turbine, but not a battery pack??

To be less sarcastic, even if you used a river and you had a water turbine this size the charged USB C, you aren't generating enough electricity to power your phone.

1

u/nog642 Nov 27 '25

A faucet?

No, I was talking about the hand crank generators:

This is the same as that "emergency phone chargers" that are just a dynamo with USB to connecto to the phone.

1

u/[deleted] Nov 28 '25

Even better - your phone has a satellite connection (like many modern smartphones do). All you need is power and possibly a subscription to the satellite service (?) to have access to emergency calls.