Question Is there a way to Bypass a power supply and use DC power directly?

[miogpsrocks]

Is there a way to Bypass a power supply and use DC power directly?

My understanding is that a power supply is taking AC input and outputting DC. So the computer/motherboard is using DC power not AC.

Situation would be sort of an offgrid setup where solar was supplying power to a battery bank.

Solar inverters have large losses when converting DC-to-AC only for a power supply then to lose power converting the AC-to-DC.

Since the power being generator is DC to begin with, you could all those AC/DC conversions along the way. DC/AC might lose 20% then AC/DC lose another 20%.

So out of every 100W generated, you might only get 60W and lose 40W in these conversions loss.

Some have suggested a DC-to-DC converter so you can specify a certain DC volts to various devices.

Has anyone ever heard of something this a direct DC being used on a computer/ server/ bitcoin miner?

 

[USAFRet]

A typical ATX power supply splits the wall power (110 or 220) into multiple different streams.
12v, 5v, etc, etc.

 

[miogpsrocks]

A typical ATX power supply splits the wall power (110 or 220) into multiple different streams.
12v, 5v, etc, etc.

I am assuming that multiple DC-to-DC converters can be setup to output various multiple streams.

12V, 5V, etc... to various parts of the computer. You might have one that is dedicated 12V and another one that is dedicated 5V, etc...

 

[USAFRet]

I am assuming that multiple DC-to-DC converters can be setup to output various multiple streams.

12V, 5V, etc... to various parts of the computer. You might have one that is dedicated 12V and another one that is dedicated 5V, etc...

Thereby designing a whole new PSU type.

 

[Eximo]

Not so much new, as specialized.

There are already existing solutions for taking direct lower voltage solar power and outputting DC for charging a 12V system. You would just tap off of that for 12V and then get high efficiency DC to DC converters, you could use components from a PC power supply.

There are also plenty of DC input capable PC hardware out there.

To run something like a laptop, a boost converter from say 12V to 19-20V, maybe 5A for a relatively light laptop is all you need. I see dozens of offerings on Amazon for such products, you would have to wire up your own connector for the laptop of course.


If you have something in between like 24 or 48V, then you could also use a high efficiency DC-DC converter there.

If you have access to high voltage DC, then you have quite a few options in using off the shelf hardware and bypassing the AC side and putting the high voltage DC directly across the main capacitors. You might have to fiddle with some of the POST circuits to make that fire up properly, but that is pretty advanced and dangerous stuff. And you would need sufficiently high voltage for that to work directly. Around 200V DC for a 110V AC capable supply, and 400V or so for a typical 240V input power supply.

If you are curious look at Vicor modular bench supplies for various DC to DC units. These are not cheap.

 

[USAFRet]

Not so much new, as specialized.

There are already existing solutions for taking direct lower voltage solar power and outputting DC for charging a 12V system. You would just tap off of that for 12V and then get high efficiency DC to DC converters, you could use components from a PC power supply.

There are also plenty of DC input capable PC hardware out there.

To run something like a laptop, a boost converter from say 12V to 19-20V, maybe 5A for a relatively light laptop is all you need. I see dozens of offerings on Amazon for such products, you would have to wire up your own connector for the laptop of course.


If you have something in between like 24 or 48V, then you could also use a high efficiency DC-DC converter there.

If you have access to high voltage DC, then you have quite a few options in using off the shelf hardware and bypassing the AC side and putting the high voltage DC directly across the main capacitors. You might have to fiddle with some of the POST circuits to make that fire up properly, but that is pretty advanced and dangerous stuff. And you would need sufficiently high voltage for that to work directly. Around 200V DC for a 110V AC capable supply, and 400V or so for a typical 240V input power supply.

If you are curious look at Vicor modular bench supplies for various DC to DC units. These are not cheap.

For a laptop, sure.
All that division of voltages happen on the laptop motherboard.

A desktop, with 20/24 pin input, then also the CPU/GPU/SATA connections - Different animal.

 

[Eximo]

For a laptop, sure.
All that division of voltages happen on the laptop motherboard.

A desktop, with 20/24 pin input, then also the CPU/GPU/SATA connections - Different animal.

There are ATX 12VO systems to pick from and motherboards designed to run off direct DC input, but that is not what I am getting at for the most part. Though the same low voltage DC to higher voltage DC converter would make such things possible if they weren't 12V input, but I know there are computers out there that are. Also not in the full up desktop levels of performance.

If you need 12V at like 100Amps for your 5090 system, then it would be some pretty expensive stuff.

Second example with access to high voltage. You can take a PSU, put DC directly into the main capacitors, and with a few bypasses, fire it up getting a VERY clean DC output. It is not wise and not that safe.

There are off the shelf solutions for off grid AC power which is more sensible, even if it is less efficient.


Here is a module that normally plugs into an AC powered backplane:

https://www.artisantg.com/TestMeasu...GuKwIbHQT7wpiz0naKYkMnH-CfgJBoFUt2NCyfY&gQT=1

Only outputs 100W at 12V, but the input is 300V DC.

Neat thing is you can put these in parallel and get a few hundred watts output, the smaller systems accepted 8 units, but they make bigger ones. Again, these are your very efficient solutions that cost a lot of money.

If you don't want DC to AC back to DC at around 70% efficiency, or less, then you have to look at some really nice things.