Any reason he could not just use a 10$ of the shelf PoE splitter?
a) because he can
b) for the lulz
c) optics
Hacker mods an M1 Mac mini to receive power over Ethernet instead of AC
111–120 of 171 posts
Re: Hacker mods an M1 Mac mini to receive power over Ethernet instead of AC
#112Earlier quoted context omitted.
Thank you for taking the time to follow up! Definitely a bit paranoid - even if I'd prefer to call it robust :) I've had very bad luck in this regard... but haven't honestly used a laptop in probably a decade. I was pleasantly surprised to see my latest (dust-collecting) Lenovo will stop somewhere around 80%! Point being, sure - there are safety things... but batteries are consumables. I like these things to be easy-…
> ... but batteries are consumables. I like these things to be easy-to-replace! Replaceable, consumable batteries often get thrown out in the trash. ... and can set garbage trucks and recycling centers on fire. https://www.waste360.com/safety/lithium-ion-batteries-are-ca... https://www.dispatch.com/story/news/local/2023/02/09/garbage... https://arstechnica.com/gadgets/2022/12/recycling-firm-fined... https://gothamist…
We can't. Instead we're making it worse by selling disposable vapes with rechargeable li-ion batteries [1].
[1] https://www.recyclingmagazin.de/2023/07/17/das-ungenutzte-po...
Re: Hacker mods an M1 Mac mini to receive power over Ethernet instead of AC
#113Earlier quoted context omitted.
Headless servers where you want a modular or easily removable battery backup. I really wish desktop PC power supplies would support such a thing. It seems stupid that we need to use a UPS with an inverter when the power supply should be rigged to accept DC input straight from a battery.
Exactly, the PC PSU coverts AC to 12v for the PC anyway, so 12v batteries should slot into that scheme, without a separate PSU and inverter.
You would still need a DC to DC converter as lead acids deliver anywhere from 12.8 to about 10v depending on SoC and load.
Re: Hacker mods an M1 Mac mini to receive power over Ethernet instead of AC
#114I've been wondering more than once if we couldn't improve (larger) offices a lot by distributing power pre-transformed so every computer and every screen wouldn't have to include a transformer. I also sometimes wonder why these days, when every new lamp is led, why we don't replace most of the dangerous 230V outlets in new houses with 12V and use 230V only for dishwashers, laundry machines, dryers and that kind of st…
Transmission losses in DC are higher, so you need a lot more wire. You actually can get off the shelf low voltage lighting, though, but it tends to be high end designer stuff.
> Transmission losses in DC are higher
For the same voltage and wire size, transmission losses in DC are the same or lower (due to skin effect and capacitive/inductive losses). They are only higher when comparing low-voltage DC with higher-voltage AC, but the key difference is the voltage, not DC versus AC.
(As a bonus, DC has lower peak voltage for the same RMS voltage, so the wires need less insulation.)
Re: Hacker mods an M1 Mac mini to receive power over Ethernet instead of AC
#115Earlier quoted context omitted.
What's the goal of having a MacMini running off an external battery? I mean, it seems less cost effective than just getting a MB Air and not using the screen...
In the event of that solar flare that wipes out the grid.
In that event, personal computing will be the least of our worries
Re: Hacker mods an M1 Mac mini to receive power over Ethernet instead of AC
#116Earlier quoted context omitted.
Headless servers where you want a modular or easily removable battery backup. I really wish desktop PC power supplies would support such a thing. It seems stupid that we need to use a UPS with an inverter when the power supply should be rigged to accept DC input straight from a battery.
Exactly, the PC PSU coverts AC to 12v for the PC anyway, so 12v batteries should slot into that scheme, without a separate PSU and inverter.
For anything larger than about 500W that'd become untenable because at 12V as you'd need cables that can carry in excess of 50A.
UPS systems start connecting the batteries in series to provide higher voltages for this reason
Re: Hacker mods an M1 Mac mini to receive power over Ethernet instead of AC
#117Has anyone accomplished powering an Apple TV with PoE?
That's what I want as well. It will/should always have an Ethernet cable attached anyway, but why do I need to run two wires?
Apples are a little weird, in that they clearly have no love for cables, yet they refuse to adopt PoE. The AppleTV and HomePods are prime candidates for PoE.
Re: Hacker mods an M1 Mac mini to receive power over Ethernet instead of AC
#118Earlier quoted context omitted.
What's the goal of having a MacMini running off an external battery? I mean, it seems less cost effective than just getting a MB Air and not using the screen...
Headless servers where you want a modular or easily removable battery backup. I really wish desktop PC power supplies would support such a thing. It seems stupid that we need to use a UPS with an inverter when the power supply should be rigged to accept DC input straight from a battery.
Even more annoying is why aren't decent USB-only ups systems?
just ditch the 110 outlets for usb-a or usb-c ports and skip the inverter.
I'd love to power a pi or 3 from ups-based usb ports.
Re: Hacker mods an M1 Mac mini to receive power over Ethernet instead of AC
#119Earlier quoted context omitted.
Exactly, the PC PSU coverts AC to 12v for the PC anyway, so 12v batteries should slot into that scheme, without a separate PSU and inverter.
For anything larger than about 500W that'd become untenable because at 12V as you'd need cables that can carry in excess of 50A. UPS systems start connecting the batteries in series to provide higher voltages for this reason
Or multiple cables, just as PC power supplies of 500w+ have, and in fact some of their power is delivered at 5v.
Re: Hacker mods an M1 Mac mini to receive power over Ethernet instead of AC
#120I've been wondering more than once if we couldn't improve (larger) offices a lot by distributing power pre-transformed so every computer and every screen wouldn't have to include a transformer. I also sometimes wonder why these days, when every new lamp is led, why we don't replace most of the dangerous 230V outlets in new houses with 12V and use 230V only for dishwashers, laundry machines, dryers and that kind of st…
Office equipment doesn't really have "transformers" anymore, everything uses switched-mode power supplies. The way they work, is that they have an output buffer (a capacitor or inductor) and rapidly turn a switch on and off to keep that output buffer at the right level: if the output buffer is below the target voltage, the switch closes and the voltage will start to rise. Once the output buffer rises above the target…
Yes, that's the tradeoff. High voltage for the long haul, low voltage locally is common.
There are computer equipment racks where distribution within the rack is at 12 VDC. These often have big busbars in the back, and a power supply in the base. Facebook's OpenRack started at 12VDC, but a later rev is at 48 VDC. That's just within the rack; there's a power supply in the rack base running off something like 3-phase 220VAC. There are advantages to running off 3-phase power; there's always power available from at least one phase, and the capacitors needed to smooth DC are far smaller.
Telephone central offices have run the whole office at 48VDC for a century, with a big battery for backup power. Big bus bars carry that around the building. (Do telco offices still do that?)
Much industrial control gear runs at 24VDC. So do many military vehicles. It's a reasonable voltage to send a few meters, but not hundreds.
(The extreme case is ultra-high voltage DC power transmission, where power is sent thousands of kilometers at a million volts.)