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Comment by ravetcofx | Hacker News Reader

" the M1 Mac mini was the perfect hardware to test out PoE, as on idle, the device only consumes 6W. When some load is applied to the internals, that power draw can go up to 40W. After some thorough research, we found out that the maximum throughput of Power over Ethernet was 15.4W "

They'll have to bump it up to 802.3bt (Poe ++) which can support 60W.

Cool Project though, I've been wanting to mod my Mac Mini m1 to run off USB-C PD which should be possible with modification because it uses the same PD IC as the Macbooks (CD3217) which could mean I could get it to eventually run off of a battery pack

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Minor correction: 802.3bt added 51W (Type 3) or 71W (Type 4). 60W isn't a standard power level. Some switches support up to 95W per port with PoH.

Surely they're all 'up to'? It's not 'you must sink this much current or else not compliant'?

It seems like a weird thing for TFA to say anyway - my PoE[+] switch was the cheapest 8 port I could get a few years ago on Amazon, and does 30W per port. I don't really understand how you could look into it at all, be willing to attempt the hack, but not use a switch (or injector or whatever) that's capable of powering it under load.

Hah, yes they are all 'up to' on the device side. A switch port or injector is not compliant with a particular standard if it does not provide for the type-specific load, however.

Depends. Within the standard, you can do 51w at the full 100m on standard cat6, which is 300ma/pair. If your runs are shorter, you should be good to go at the full type4 current, or, 960ma.

This is a good reference for this: https://www.5gtechnologyworld.com/what-every-engineer-should... which goes into how to calc your total bundle dissipation and whatnot.

“By ‘Energy Star’ compliant, we mean that it burns as much energy as the sun.”

They said it "can support 60W." As you point out, Type 4 can support up to 71W, so yes it can support 60W. They didn't assert that it is a standard power level.

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...

The goal of most of these projects are usually to demonstrate that they're possible. Actual use cases are left as an exercise for the reader.

> it seems less cost effective than just getting a MB Air and not using the screen...

how ? why would paying for a screen and not use it be cheaper ?

Economy of scale, mostly.

Avoiding the inevitable spicy pillow seems like a good reason

An external/easily replaceable battery would be excellent come time to deal with cell age

Does this read like an attack against Apple laptops specifically, or something? Already -2 five minutes after posting it.

Leaving as-is for feedback. I don't get the controversy. I could've been a jerk and said just buy a UPS - this is an established concept.

Edit: thank you kind souls for restoring the imbalance - carry on :D

No it just reads as kinda paranoid because li-ion cells typically become spicy pillows long after the device becomes obsolete. It's also trivial to avoid by limiting cell voltage. Many devices, most notably iPhones, automatically go into kiosk mode after charging for a few days for exactly this reason: https://support.apple.com/en-gu/HT208710

Definitely disagree. My own anecdotal evidence is that many many laptops left plugged in 24/7 will develop a spicy pillow after a year or two. That includes a set of Apple laptops and hundreds of Dell laptops.

Anecdotally: this has never happened to me despite owning a whole bunch of laptops over the past 25 years or so.

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-to-replace!

I find these being difficult to replace accelerates this pattern of obsoleting. CPUs and (especially disks) tend to pack plenty of punch/life, these days - well beyond the mechanical/chemical things they depend on.

Something to ponder - these chips may see particularly long use, being so power efficient. The utility bill won't be such a driver, sipping power and parallelizing decently.

> ... 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.com/news/lithium-ion-batteries-a-growing-f...

https://www.abc.net.au/news/2023-05-29/garbage-truck-fires-c...

(and many more)

How does one make sure that removable, consumable, high capacity batteries are not discarded as trash but instead taken to the proper facilities to handle them?

Is the dichotomy here really that we can either have modular batteries, or we can have more intact waste trucks and workers?

However, having just taken an entire stroller out of my shared duplex recycling bin, I know there will never be an ethical way to get 100% of people to care enough to dispose of waste properly.

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...

I wish I knew a good answer - this is an excellent concern. I'm skeptical of recyclers/waste centers, but that's what I've got.

Having things that are have special handling for disposal not be as user serviceable is one solution... but that goes against the replaceable battery.

The AA lithium ion batteries getting tossed into the trash and setting garbage trucks on fire are problematic enough. The energy capacity of a cell phone is quite a bit more and correspondingly more spectacular in the combustion.

From iFixit:

https://www.ifixit.com/News/69041/how-batteries-can-catch-fi...

https://www.ifixit.com/News/34034/lithium-ion-batteries-are-...

> USA Today reports that 65 percent of fires at waste facilities in California were started by lithium-ion batteries. In a 2018 survey of 21 waste facilities across California, 86 percent reported a fire at their facility in the last two years, according to the California Products Stewardship Council (CPSC). Of those fires, 56 percent were attributed to batteries, with the remainder attributed to “traditional hazards of combustibles.” In other words, batteries are causing more fires than the oils, fuels, and other hazardous materials of waste management—combined.

> And that’s only the fires actually reported.

Respectfully, today people just chuck the entire phone/laptop in the bin. I don’t think making the battery module removable changes the outcome one bit, except that it would allow a tremendous amount more life out of these devices, reducing all the other (non-battery) waste streams and reducing the environmentally costly manufacture of new devices…. which is the reason why the shareholders love the current strategy and why all electronic manufacturers are moving the same way. Why allow users to get 3 more years of life from their laptop when you could convince them it’s e-waste after 3 because of a $15 battery?

Not really. However, as a long-time Mac and Apple fan, I can say the community has a lot of overly aggressive people who can't stand any criticism (valid or not) of Apple and will do various things in retaliation.

heh, I understood what you meant by "spicy pillow" from context but it's a new phrase for me, I like it

Can you explain

lipo batteries expand

https://www.reddit.com/r/spicypillows/

The batteries puff up like an overstuffed pillow and if you let the spice out, you're going to have a bad time.

The article is about a Mac Mini. Those machines are mains powered, not battery powered.

I was replying to a question on why one wouldn't "just get a MB Air/not use the screen"... not the article.

How is this relevant? I don't say this to be rude, but this internet phenomenon of relentless pedantry is annoying.

Things tend to make [some degree of] sense when your first reaction isn't to shoot from the hip.

Mains batteries exist - most people should save the effort, get a UPS. Hackers on the other hand... it's kind of silly to ask why. The answer is 'because'.

cheaper and bigger batteries? always replaceable in the future? And tbh laptop batteries are not meant to be used 24/7, personally would avoid it.

No idea, but if they got it running on USB PD, battery pack aside, it would make it a one cable connection to a monitor that has PD support. Multiple cords don’t actually bother me but it sounds kinda neat.

Anyhow I guess the goal is “because you can”

This would be fun for when LEOs come in to take your computer, they can easily keep it powered so all of the decrypted keys stay in memory. Killing power means going back to an encrypted state. In high profile cases for desktops, there's techniques for splicing the power cable to switch to a battery pack. This would make it much easier for the unskilled LEO to take your shit. Cause we all know you're the one they're after. Sleep tight! ;-)

That's why pretty much all desktop and server mobos have a "chassis intrusion" header that you can connect to a sensor/switch. Your machine should wipe keys or reboot if it's opened or moved.

how does that work if the case is never opened?

You can connect multiple switches in series. Eg one could be a reed switch that detects whether the PC is within 1mm of a tiny magnet in the floor.

This is a good idea! Kind of makes me wish I was a drug kingpin with a PC full of secrets so that I could justify trying that. Sadly I would just end up with a kid rebooting the PC by bumping into it :D

I could see it making sense in a 'van life' context to use a smaller local battery rather than plug everything in to your main leisure battery. Use the latter to charge Makita packs say and then run most other stuff off those (there's a decent amount of open 3D printable adapters for them, as well as third-party/AliExpress stuff).

Would make way way more sense to have a macbook that you can then charge direct from a DC battery over USB-C. With the mac mini you still have to work out how to power an external screen as well.

There's a lot of low power HD screens out there. It's not super difficult. Not the ideal case for sure but low power is all about tradeoffs.

That it happens to be 12 volts DC has some value versus whatever power loss an inverter has for use in a vehicle. Though I'm with you on the relative ease of starting with a laptop instead.

Two large monitors or projectors with Mac mini.

E.g. to run home automation in case of a power outage. I have an Intel NUC with a li-ion DC UPS exactly for this reason.

Battery aside, POE also allows you to put it anywhere you have ethernet cable with sufficient power delivery. In this case you could have a workstation powered entirely off ethernet delivered to the location (some monitors will also work with a POE splitter as well).

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.

Remember that DC to DC power supplies are much smaller because existing AC PSU has to deal with the transformer aspect.

I worked for an ISP that was also a CLEC back in late 90s / early 2000s. All of the telco side was DC (massive 48v battery banks) - so when we were doing server implementation it made sense to get all DC PSU on the servers. Not sure why DC PSU aren't a more universal option as you'd think UPS providers could easily offer DC output models.

There are options out there, I ran across this [0] looking for typical ATX DC to DC PSU.

[0] https://lazer3d.com/dc-dc-power-supply-guide/

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.

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.

Where I live, this is actually extremely common now - typically referred to as a "Mini DC UPS" [1].

These cheaper ones just provide 9V and 12V output to power a fibre and/or WiFi router, as well as 5V USB-A, and start at around 30Wh capacity - some for less than USD 20. If you pay a little more, you can get 24/48V PoE included as well.

Unfortunately, ones providing USB-PD are quite rare. You do get "power stations" [2] with USB-PD (in addition to an AC inverter). These are typically USD 100 - USD 1000, and have much larger capacity.

Examples (I haven't tested these and do not specifically recommend them):

[1]: https://www.amazon.com/Lithium-Battery-Appliance-Monitor-uni...

[2]: https://www.amazon.com/Portable-Solar-Panel-Power-Station-Ge...

Yeah that would be great. Pimoroni makes a version of the Pi Pico that takes a LiPo battery and automatically switches to battery power when the USB power goes away, but I don't know of any full computers that support that. I think adafruit makes a LiPo addon for picos. I wonder if it could be modded to work on a zero or something?

That's where USB-C PD is nice. It's all DC at several different voltages the recipient can request. The only downside is it's not quite powerful enough for many desktop PCs, but it's getting better.

Pretty much expect the Mini to end up this way within a few generations. Somebody in the Mac team really hates wall warts, but given all their other hardware is going USB-C one would think they’d want to standardize & eliminate the space/heat of the internal power supply.

In the event of that solar flare that wipes out the grid.

In that event, personal computing will be the least of our worries

I'm going to try this with my extra Mac mini and one of my switches that outputs POE++ at the full 60w. I should even be able to do this using a fairly bog-standard POE splitter from POE Texas that'll actually deliver a full 60W.

Edit: Here's the injector I'll probably use - https://shop.poetexas.com/collections/splitters/products/gbt...

This change/mod involving one of the most locked-down devices seems pointless. What do you like about the project? Or is it that the additional cable is so irksome?

I have my own "must-do" projects that from outside perspective is seen as pointless. So, this is more about understanding than poking holes.

Another way to look at it, you can put one of the most powerful mini computers at the edge with PoE, think machine vision with industrial USB camera type of scenario.

If you don't get PD working, you can always just build a battery pack that charges itself over USB-PD, and outputs 12V. Apparently the built in PSU on the Mini takes 120/240V and outputs nothing but 12.

I’d be very curious to understand (even very crudely) the breakdown of those 40W. Roughly how much does each internal component consume at its peak load? Or at least for the top offenders.

80%+ will be the M1/M2 SOC with it's on package Ram, ~5% will be SSD, 5%-10% Fan, remaining will be supporting circuitry (buck converters, regulators etc)

I'm very skeptical of PoE now after 3 PoE adapters killed 3 Raspberry Pis I have.

I wouldn't want to risk something more expensive to that shit.

At this point I'd rather just have straight up 19V + and - cables bundled together with the Ethernet with some heatshrink around the whole thing to make it look like 1 cable.

You sure you want to blame poe as a whole instead of the RPI hat?

Sure it could be the RPi hat, but it just means the standard is so complicated that people don't implement it correctly.

I wouldn't trust the hat or whatever you call it for Mac Mini.

> Sure it could be the RPi hat, but it just means the standard is so complicated that people don't implement it correctly.

Or there are ways to cheap out on a PoE device that may work in some cases but don't fully and properly implement the standard.

The standard is widely used in VoIP phones, wireless access points, security cameras, and all sorts of other networked devices that get installed in places that may not have nearby power outlets or where a single wire solution is beneficial.

Personally I have three Pis that have been on PoE their entire lives and have had no problem, but I used a name brand PoE hat (the Waveshare hat with the OLED display) and am powering them from a mainstream PoE switch. If you're using some random AliExpress hat with janky injectors you get what you pay for.

> I wouldn't trust the hat or whatever you call it for Mac Mini.

Almost any large commercial building has had hardware running on PoE that costs more than the average Mac Mini for years. Most PTZ cameras for example, high-end directional wireless bridges, even some nicer wireless access points.

I mean, one of my hats that fried one of my Pis was a Waveshare hat. This one actually

https://www.amazon.com/gp/product/B0974TK3KD/

PoE operates at a pretty high voltage (almost half of line voltage!) and Waveshare products aren't UL listed.

>PoE operates at a pretty high voltage

No, it operates at ELV (extra-low voltage): https://en.wikipedia.org/wiki/Extra-low_voltage

The whole point of PoE, 48V PD USB-C, and similar tech is that they don't need to be UL listed. PoE is also electronically current limited unlike mains power so you can't pull 200A to start a motor nor can you start fires without a lot of effort. That's assuming you use a real PoE switch that negotiates power levels, not cheap passive injectors.

Anyway that hat has some bad reviews claiming DoA, missing components, and dead Pis. Why not get the official hat? https://www.raspberrypi.com/products/poe-hat/

You're dealing with the same manufacturers that won't even bother to include the USB C termination resistors required to make "USB C" charging ports on their devices work with actual USB-compliant PD. You're talking about the kind of part that's so cheap that adding five of them is going to round down below a penny in your BOM. The kind of manufacturer that, if it had a motto, that motto would be "no corner too cheap to cut".

It’s definitely that.

PoE is fine and the issue surely lies on some $5 Chinese rasppi part with little buffering and protection circuitry.

PoE is used extensively in network deployments involving rather expensive hardware.

I understand the instinct to avoid it at this point, but I’m curious what happened in your case because I’ve never experienced issues.

I did work somewhere where someone fried equipment by incorrectly terminating a batch of Ethernet cables thereby sending voltage to the wrong place.

That should only be possible if using non-standard "passive" PoE?

802.3bt has negotiation specifically to prevent faulty cables/devices from being powered.

I have 13-15 devices running over PoE at my house and all of them work just fine. Everything from the high end Ubiquiti gear to raspberry 3/4 PoE hats. It’s powered by a Unifi 24 port PoE switch.

The only time I had issues was with a 2 mesh APs and sketchy power at a condo that has minor power outages due to thunderstorms. I brought the devices back home and they work fine, the new device doesn’t have an issue. I was curious if a UPS would’ve smoothed the power blips but the new AP restarts and connects just fine.

PoE switches and devices are widely used in industry. I suspect your 3 PoE adapters are "passive PoE" consumer crap that doesn't meet spec

What kind of PoE Adapter/Hat did you use?

From memory, and it's been a few years/models... but the GPIO pins, including the 5V input pin bypassed all of the circuit protection fuses and what-not the normal barrel jack had.

It wasn't uncommon for people to roast their RPi with incorrectly done, or poor quality GPIO powering devices.

This is still true. There are ample warnings to be careful when using the GPIO as input because of this. The hat probably passed on some variance that is supported by actual consumer devices and fried the RasPi because it has no protections.

Don’t buy eBay junk and blame it on the standard - which is used by tons of high end commercial equipment and is more appropriately a commercial feature - PoE isn’t cheap - if it is that probably explains your poor results.

When it is off you can charge it with a simple mobile phone charger.

i would actually like being able to power my mac mini with just a usb-c dock like a macbook

Might be too easy to disconnect compared to a regular power cable.

I have been thinking it would be cool to just salvage a functional MacBook Air motherboard from a “broken” device. install that in a small case, 3D print an IO shield, and you have what you’re looking for!

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