6 ms·

I was going to criticize & point out how usb-c chargers at and over 100W are just so small, but there's a photo comparing it to an iphone & ok, it looks adequat

I was going to criticize & point out how usb-c chargers at and over 100W are just so small, but there's a photo comparing it to an iphone & ok, it looks adequately impressively dense! (I have a >2 year old 100W charger that is 66x64x30mm, this 250W unit is 170x50x25) It's been such a great synergy. Energy efficiency has been a concern already yes, but I really view usb-c chargers as pushing the consumerization & massification & development of this technology to the superb, common, un-exotic levels it's come down to. We just got tired of doing less good, actively explored trying to use a somewhat harder to drive switching semiconductor, & have reaped great rewards. Miniaturization mandated optimization & we all win. I really think the interchangable-parts/modularity & resulting competition that usb-c begot started this ball rolling. (Hoping USB-PD, with it's bump from 20 up to 48V, once again proves another huge win!)

rektide 4y ago
I'd also point to Google's Little Box Challenge[1] as an interesting data-point of yore. Little Box Challenge went the other direction: instead of taking AC and producing DC power, it was an inverter that took DC power and produced AC output. It had to output 2kW and be smaller than 655 cubic centimeters (cc's). The winning Red Electrical Devil's team got 3x more dense than this[2]! 240 cc's! While inverting 2kW of juice. Second place was 340ccs. I don't know whether we'd argue this DC->AC is harder/easier than an ATX supply (AC->DC) (probably not?) but this was quite an impressive competition, almost a decade ago, that resulted in probably some of the most power-dense, highest-efficiency power conversions that humanity has ever gotten up to. For compare, this 250W unit is 212cc's. 8x less power conversion, 88% the size. The Little Box Challenge designs were published, so there's a ton of great reading. Alas, Google frakking let the damned site bitrot off the net?! Sooo, head to archive.org[3] to read the team's writeups. From the winning CET Red Electric Devils writeup: > GaN transistors have many very interesting electrical characteristics (low Rds_on, low Qgate and Cds, ultra low Qrr); these create technological advantages over current MOSFET and IGBT devices (small size and low production costs). Unfortunately, they also have serious drawbacks due to their very fast switching characteristics: they are challenging to drive and require sensitive electromagnetic noise management. Another pitfall is the high voltage drop due to the reverse current when the GaN is turned off. The solution selected to overcome these difficulties is to control all the GaN transistors using soft switching for the entire operation range. [1] https://news.ycombinator.com/item?id=8070215 https://news.ycombinator.com/item?id=8070215 (271 points, 8 years ago, 138 comments) [2] https://ai.googleblog.com/2016/02/and-winner-of-1-million-little-box.html https://ai.googleblog.com/2016/02/and-winner-of-1-million-li... [3] http://web.archive.org/web/20171006105655/https://littleboxchallenge.com/ http://web.archive.org/web/20171006105655/https://littleboxc...
- elihu 4y ago
  I'm doing an EV conversion, and have trouble wrapping my head around the idea that a motor controller that weighs about ten pounds or so and isn't much bigger than a loaf of bread can handle about 100 kilowatts of power, converting DC at around 140-180 volts from the battery to 3-phase AC. And that's a relatively low-end inverter.
  - virginiadoolf 4y ago
    the answer is liquid cooling. these Little Box and ATX power supplies have to rely on passive cooling (radiative, conductive, and convective) which is generally proportional to surface area == physical size ^ 3. if you halve the size, then, you lose 87.5% of the surface area! that's why these things can't shrink as much. but ultimately the silicon involved is miniscule.
    - MauranKilom 4y ago
      Not to detract from your point, but surface area scales with size ^ 2.
    - elihu 4y ago
      Technically my motor controller can be passively cooled too, it's just not recommended. (It automatically goes into a low-power "limp" mode rather than burn itself out.) I'm not sure how much power it can handle continuously in a pure passive-cooling mode.
    - wolrah 4y ago
      It would also be worth noting that a typical EV doesn't have to run at anything close to 100% load for extended periods of time. What sort of power an electric drivetrain can handle for a burst of acceleration lasting a few seconds versus what that same drivetrain can handle as a continuous load are two very different things. The same even applies with combustion powered cars too, if you look at the pickup truck market you'll see massive power numbers on every manufacturer's diesel pickups. If you look at their chassis-cab commercial trucks those same diesel engines are often derated by 30-50% compared to the pickups even while being equipped with larger cooling systems. That's because the commercial variants are rated to perform to spec all day every day where the pickup version just needs to put a grin on the owner's face when they floor it off the line and then occasionally tow a boat or something.
_delirium 4y ago
I've found high-wattage USB-C chargers to have very poor reliability. All the 18-W chargers I've owned have lasted multiple years, but the compact 90-W+ chargers have a lifespan measured in months. Of course, they all purport to offer a warranty, but if you try to claim, they will not honor it. They will claim it's because you bought from Amazon and they don't warrant Amazon purchases (despite this being their main retail outlet, and the fact that they advertised the warranty IN the Amazon sales materials). Or something similar.
- rektide 4y ago
  I have a ravpower, a hyper, and just bought the new ugreen. The ugreen is too new to judge, but the others have ran for over two years, and a good amount of that time has been outdoors in the sun. I constantly expect failures. This seems like an absurd task I'm putting them up to. But they are all still alive & doing the job. I've had a kill-a-watt so I can see their power consumption. A large amount of their life is spent ~60 watts, but there's definitely hours on end & heavy usage days, where they go up to or stay at 90+. My anecdotal data looks different than yours.
  - _delirium 4y ago
    My Ravpower device died within 8 months, and they refused to honor the warranty, giving as the reason that the purchaser of record was Amazon LLC, not Ravpower. Even though they advertised a warranty on their Amazon page, which was the main way they sold the devices.
    - retcon 4y ago
      ... dreams of the EPA obtaining warrants for the fraud on the public for the disposal costs of so much wasted electronics...
    - londons_explore 4y ago
      In the EU you get 2 years warranty for all items from every retailer by law, and most generally honour them.
NavinF 4y ago
> this 250W unit is 170x50x25 They’ve been selling a 400W (still fanless!) DC-DC version for years and it’s only 160x51.5x26mm : https://hdplex.com/hdplex-400w-hi-fi-dc-atx-power-supply-16v-24v-wide-range-voltage-input.html https://hdplex.com/hdplex-400w-hi-fi-dc-atx-power-supply-16v... I use it to power my CPU+mobo but I also have a couple of server PSUs further away to power my 3090 over several pairs of THNN. It’s far from a SFF build, but it can be totally silent.
- morganvachon 4y ago
  The difference is that this unit does the AC-DC conversion inside itself, whereas your DC-DC power supply relies on an external AC-DC brick that is likely the same size as this entire self contained unit, if not larger.
  - bombcar 4y ago
    If you're dealing with solar or a vehicle you may already have DC available; too bad it can't take -48v which some racks still supply.
- dwild 4y ago
  To be a fair comparison would need to include the AC-DC power supply that you keep outside to power that thing... it's double the size once you account for that.
  - NavinF 4y ago
    More like 3x. My Emerson 7001484-J000 PSUs go full depth into a server chassis. But that’s a sunk cost since it’s much easier to build a 12VDC UPS instead of a 120/240VAC UPS
jsmith45 4y ago
I my complaint that they are calling this atx, when the only thing remotely ATX about it is being designed to work with the atx motherboard power connector. This in no way meets the atx form factor for power supplies, neither the original, nor the 12V version. Like I could forgive it if it failed to be a rectangular prism in favor of having more open space, as long as it had a frame with proper mounting points. And I could also forgive it if they went with the rectangle, but far shorter than the official 140mm depth (that has always been mandatory per intel specs), given that the market already accommodates non-conforming lengths, and this could be made to not require the bottom of case mounting holes, allowing for absurdly short lengths. But the photos show none of that, and just a fully custom form factor, without any apparent mounting mechanism.
- vxNsr 4y ago
  This actually looks like a server psu.
- tomtheelder 4y ago
  The form factor and mounting design of the power supply are not parts of the ATX spec. The pin layout & shape, voltages, signaling, etc are what are specified. This is an ATX power supply. It is just designed for very small cases that would never be able to accommodate the existing standard configurations.
  - D13Fd 4y ago
    >The form factor and mounting design of the power supply are not parts of the ATX spec. The pin layout & shape, voltages, signaling, etc are what are specified. Did you just pull this out of nowhere? Look at ATX Specification v. 2.01 section 4.1, page 18-20. It specifies the "required overall dimensions and general form factor of an ATX power supply," with or without special airflow ducting (emphasis in original). The linked PSU in the OP clearly does not meet this form factor.
    - tomtheelder 4y ago
      That's a very outdated spec. The size requirements were removed in the current spec.
hangonhn 4y ago
> (Hoping USB-PD, with it's bump from 20 up to 48V, once again proves another huge win!) Can someone explain to me why 48V? Is there something special with 48V or beyond? The reason I ask is because some cars now have electric turbos and the manufacturer had to switch to a 48V system. Just curious what the benefits of higher voltage is and if 48 is somehow special. Thanks in advance.
- aparks517 4y ago
  Power is the product of current and voltage. To transfer much power at a low voltage requires a large current. Supporting a large current without getting hot and melting requires large-diameter wire. Other components may also be bulky or expensive if they have high current-handling requirements. I seem to recall that somewhere around 50 volts is a magic number from a safety/regulatory perspective. It might also have something to do with semiconductor breakdown voltage, but maybe I'm out of date on that.
- Dave_Rosenthal 4y ago
  My understanding is that 50V is the established threshold above which safety to humans starts to be a factor. So, applications that want high powers, without the penalty of large wires nor the penalty of the safety requirements of an HV system, converge to 48.
  - avhon1 4y ago
    > the established threshold above which safety to humans starts to be a factor Specifically, 50 volts is approximately the threshold above which electricity can pass through the skin and shock you. Lower voltages will only shock humans if they have a way to bypass some of the skin, like wounds or tight-fitting metal jewelry. Otherwise, the resistance of skin is high enough to prevent the flow of electricity. That's why you can touch both terminals of a 12V car battery at the same time and almost certainly not be shocked.
- spookthesunset 4y ago
  At 48v you can use much smaller gauge wire than at 12v. Which means lower cost, less weight and a smaller footprint for your wire harnesses. One of the things that can “get you” with these higher voltage systems is you can’t use them to jumpstart the present majority of cars. While I’ve yet to actually see a higher voltage car, I would hope they’d put warnings by the battery to remind the user that “hey, don’t try to jumpstart your friends car with this battery!”

rektide 4y ago

I'd also point to Google's Little Box Challenge[1] as an interesting data-point of yore. Little Box Challenge went the other direction: instead of taking AC and producing DC power, it was an inverter that took DC power and produced AC output. It had to output 2kW and be smaller than 655 cubic centimeters (cc's). The winning Red Electrical Devil's team got 3x more dense than this[2]! 240 cc's! While inverting 2kW of juice. Second place was 340ccs. I don't know whether we'd argue this DC->AC is harder/easier than an ATX supply (AC->DC) (probably not?) but this was quite an impressive competition, almost a decade ago, that resulted in probably some of the most power-dense, highest-efficiency power conversions that humanity has ever gotten up to. For compare, this 250W unit is 212cc's. 8x less power conversion, 88% the size. The Little Box Challenge designs were published, so there's a ton of great reading. Alas, Google frakking let the damned site bitrot off the net?! Sooo, head to archive.org[3] to read the team's writeups. From the winning CET Red Electric Devils writeup: > GaN transistors have many very interesting electrical characteristics (low Rds_on, low Qgate and Cds, ultra low Qrr); these create technological advantages over current MOSFET and IGBT devices (small size and low production costs). Unfortunately, they also have serious drawbacks due to their very fast switching characteristics: they are challenging to drive and require sensitive electromagnetic noise management. Another pitfall is the high voltage drop due to the reverse current when the GaN is turned off. The solution selected to overcome these difficulties is to control all the GaN transistors using soft switching for the entire operation range. [1] https://news.ycombinator.com/item?id=8070215 https://news.ycombinator.com/item?id=8070215 (271 points, 8 years ago, 138 comments) [2] https://ai.googleblog.com/2016/02/and-winner-of-1-million-little-box.html https://ai.googleblog.com/2016/02/and-winner-of-1-million-li... [3] http://web.archive.org/web/20171006105655/https://littleboxchallenge.com/ http://web.archive.org/web/20171006105655/https://littleboxc...

elihu 4y ago
I'm doing an EV conversion, and have trouble wrapping my head around the idea that a motor controller that weighs about ten pounds or so and isn't much bigger than a loaf of bread can handle about 100 kilowatts of power, converting DC at around 140-180 volts from the battery to 3-phase AC. And that's a relatively low-end inverter.
- virginiadoolf 4y ago
  the answer is liquid cooling. these Little Box and ATX power supplies have to rely on passive cooling (radiative, conductive, and convective) which is generally proportional to surface area == physical size ^ 3. if you halve the size, then, you lose 87.5% of the surface area! that's why these things can't shrink as much. but ultimately the silicon involved is miniscule.
  - MauranKilom 4y ago
    Not to detract from your point, but surface area scales with size ^ 2.
  - elihu 4y ago
    Technically my motor controller can be passively cooled too, it's just not recommended. (It automatically goes into a low-power "limp" mode rather than burn itself out.) I'm not sure how much power it can handle continuously in a pure passive-cooling mode.
  - wolrah 4y ago
    It would also be worth noting that a typical EV doesn't have to run at anything close to 100% load for extended periods of time. What sort of power an electric drivetrain can handle for a burst of acceleration lasting a few seconds versus what that same drivetrain can handle as a continuous load are two very different things. The same even applies with combustion powered cars too, if you look at the pickup truck market you'll see massive power numbers on every manufacturer's diesel pickups. If you look at their chassis-cab commercial trucks those same diesel engines are often derated by 30-50% compared to the pickups even while being equipped with larger cooling systems. That's because the commercial variants are rated to perform to spec all day every day where the pickup version just needs to put a grin on the owner's face when they floor it off the line and then occasionally tow a boat or something.

_delirium 4y ago

I've found high-wattage USB-C chargers to have very poor reliability. All the 18-W chargers I've owned have lasted multiple years, but the compact 90-W+ chargers have a lifespan measured in months. Of course, they all purport to offer a warranty, but if you try to claim, they will not honor it. They will claim it's because you bought from Amazon and they don't warrant Amazon purchases (despite this being their main retail outlet, and the fact that they advertised the warranty IN the Amazon sales materials). Or something similar.

rektide 4y ago
I have a ravpower, a hyper, and just bought the new ugreen. The ugreen is too new to judge, but the others have ran for over two years, and a good amount of that time has been outdoors in the sun. I constantly expect failures. This seems like an absurd task I'm putting them up to. But they are all still alive & doing the job. I've had a kill-a-watt so I can see their power consumption. A large amount of their life is spent ~60 watts, but there's definitely hours on end & heavy usage days, where they go up to or stay at 90+. My anecdotal data looks different than yours.
- _delirium 4y ago
  My Ravpower device died within 8 months, and they refused to honor the warranty, giving as the reason that the purchaser of record was Amazon LLC, not Ravpower. Even though they advertised a warranty on their Amazon page, which was the main way they sold the devices.
  - retcon 4y ago
    ... dreams of the EPA obtaining warrants for the fraud on the public for the disposal costs of so much wasted electronics...
  - londons_explore 4y ago
    In the EU you get 2 years warranty for all items from every retailer by law, and most generally honour them.

NavinF 4y ago

> this 250W unit is 170x50x25 They’ve been selling a 400W (still fanless!) DC-DC version for years and it’s only 160x51.5x26mm : https://hdplex.com/hdplex-400w-hi-fi-dc-atx-power-supply-16v-24v-wide-range-voltage-input.html https://hdplex.com/hdplex-400w-hi-fi-dc-atx-power-supply-16v... I use it to power my CPU+mobo but I also have a couple of server PSUs further away to power my 3090 over several pairs of THNN. It’s far from a SFF build, but it can be totally silent.

morganvachon 4y ago
The difference is that this unit does the AC-DC conversion inside itself, whereas your DC-DC power supply relies on an external AC-DC brick that is likely the same size as this entire self contained unit, if not larger.
- bombcar 4y ago
  If you're dealing with solar or a vehicle you may already have DC available; too bad it can't take -48v which some racks still supply.
dwild 4y ago
To be a fair comparison would need to include the AC-DC power supply that you keep outside to power that thing... it's double the size once you account for that.
- NavinF 4y ago
  More like 3x. My Emerson 7001484-J000 PSUs go full depth into a server chassis. But that’s a sunk cost since it’s much easier to build a 12VDC UPS instead of a 120/240VAC UPS

jsmith45 4y ago

I my complaint that they are calling this atx, when the only thing remotely ATX about it is being designed to work with the atx motherboard power connector. This in no way meets the atx form factor for power supplies, neither the original, nor the 12V version. Like I could forgive it if it failed to be a rectangular prism in favor of having more open space, as long as it had a frame with proper mounting points. And I could also forgive it if they went with the rectangle, but far shorter than the official 140mm depth (that has always been mandatory per intel specs), given that the market already accommodates non-conforming lengths, and this could be made to not require the bottom of case mounting holes, allowing for absurdly short lengths. But the photos show none of that, and just a fully custom form factor, without any apparent mounting mechanism.

vxNsr 4y ago
This actually looks like a server psu.
tomtheelder 4y ago
The form factor and mounting design of the power supply are not parts of the ATX spec. The pin layout & shape, voltages, signaling, etc are what are specified. This is an ATX power supply. It is just designed for very small cases that would never be able to accommodate the existing standard configurations.
- D13Fd 4y ago
  >The form factor and mounting design of the power supply are not parts of the ATX spec. The pin layout & shape, voltages, signaling, etc are what are specified. Did you just pull this out of nowhere? Look at ATX Specification v. 2.01 section 4.1, page 18-20. It specifies the "required overall dimensions and general form factor of an ATX power supply," with or without special airflow ducting (emphasis in original). The linked PSU in the OP clearly does not meet this form factor.
  - tomtheelder 4y ago
    That's a very outdated spec. The size requirements were removed in the current spec.

hangonhn 4y ago

> (Hoping USB-PD, with it's bump from 20 up to 48V, once again proves another huge win!) Can someone explain to me why 48V? Is there something special with 48V or beyond? The reason I ask is because some cars now have electric turbos and the manufacturer had to switch to a 48V system. Just curious what the benefits of higher voltage is and if 48 is somehow special. Thanks in advance.

aparks517 4y ago
Power is the product of current and voltage. To transfer much power at a low voltage requires a large current. Supporting a large current without getting hot and melting requires large-diameter wire. Other components may also be bulky or expensive if they have high current-handling requirements. I seem to recall that somewhere around 50 volts is a magic number from a safety/regulatory perspective. It might also have something to do with semiconductor breakdown voltage, but maybe I'm out of date on that.
Dave_Rosenthal 4y ago
My understanding is that 50V is the established threshold above which safety to humans starts to be a factor. So, applications that want high powers, without the penalty of large wires nor the penalty of the safety requirements of an HV system, converge to 48.
- avhon1 4y ago
  > the established threshold above which safety to humans starts to be a factor Specifically, 50 volts is approximately the threshold above which electricity can pass through the skin and shock you. Lower voltages will only shock humans if they have a way to bypass some of the skin, like wounds or tight-fitting metal jewelry. Otherwise, the resistance of skin is high enough to prevent the flow of electricity. That's why you can touch both terminals of a 12V car battery at the same time and almost certainly not be shocked.
spookthesunset 4y ago
At 48v you can use much smaller gauge wire than at 12v. Which means lower cost, less weight and a smaller footprint for your wire harnesses. One of the things that can “get you” with these higher voltage systems is you can’t use them to jumpstart the present majority of cars. While I’ve yet to actually see a higher voltage car, I would hope they’d put warnings by the battery to remind the user that “hey, don’t try to jumpstart your friends car with this battery!”