Discussion PSU with both 120VAC and 12~16VDC or 24VDC input

[dc443]

I got a Tesla recently and it's motivating me to try to see if i can do some VR gaming on the go (not while driving of course ).

My plan is that I will obtain or build (around 200x 18650s) a ~2kWh power bank that I can keep in the car, and it can trickle charge from the car's 12V battery, and this device would have a 500W or so inverter that I can power my SFF PC (as well as other small appliances) from.

However, in the name of efficiency in removing alternating current from the loop, I'm really curious if there are any PC PSU products that can allow me to keep my SFX PSU inside the SFF case while allowing me to power on the machine either using 120VAC or a DC input, say 24VDC from the battery bank.

Let's say I properly undervolt my GPU and CPU so that it stays under 400W at all times. I could potentially run the 400W HDPLEX, I may be able to make it fit in the case or I can adjust things as necessary. But the main question is how does one go about multiplexing two PSUs for one computer. The PSU wires need to be spliced up, and I could put a physical switch on the power-on wire, but PSUs may not handle it well if all of a sudden all of its rails get powered by a second PSU...

Anybody got some ideas? There's definitely enough leeway to do it the regular way and use 120VAC but I think at least the thought exercise is worth pursuing.

I'm aware I could just convert the PC to run DC internally and just use a pair of power bricks at home. But this would be farther from ideal. For example not nice for when I want to temporarily use the PC in the living room. Having more stuff hanging out when under the DC use case is more suitable as that is the less common use case. And it would need to not have wires coming out and stuff. For example the PCIe power cables for the GPU are going to be completely inaccessible.

 

[jakejm79]

Why not set the PC to run from a single 12V supply, then use an internal AC-DC PSU. When in the car you effectively plug in between the AC-DC unit and the DC-ATX unit and then when at home you plug into the AC-DC unit. If you are worried about 12V in the car back feeding the AC-DC PSU then just use a power jack that effectively breaks the connection when the plug is inserted, that way when in the car its like the AC-DC unit isn't even connected.

I'm not sure why you would need 2 power bricks at home, you can always make your own if you don't think you can find a single one with adequate wattage.

 

[timginter]

I really like the idea

If you mean using two 12v bricks because there are none powerful enough, I tried using 2x DELL DA-2 for a total of 440W and if PSUs are not designed to be master+slave, getting them to share the load is a proper pain. I modded a 750W server PSU in the end, but @REVOCCASES or @guryhwa may be able to source one brick along 500W with a more professional finish.

For the battery, if you go with a 3S 11.1V LiPo config, a CCCV charger and a good separate-ports BMS, you could solder some XT90 connectors and use a GxR-ONE 12v 600W DC-ATX plug-in PSU directly the BMS. I tried that setup in this post and it works

Parts I used:

• ZIPPY Compact 8000mAh 3S1P 30C Lipo Pack
• Separate Ports 3S LiPo 11.1V 60A BMS from Daly
• Voltage Converter 400W DC-DC Step-up Boost Converter Constant Current Power Supply Module LED Driver (see this video for details)
• 2x male, 2x female XT90-S (anti spark) plugs

Just keep in mind that the voltage range of a 3S 11.1V LiPo config is actually 9.8-12.6V and it's outside of the spec of GxR-ONE.
Lower voltage should not damage anything, your PC should just shut down. I drained the battery as low as 10.4V and PC was still running fine.
The max voltage is 12.6V, though - exactly the same as the max on GxR-ONE so double-check the max voltage after the BMS. If it's still 12.6V at max charge, a diode or a small resistor to knock voltage down a bit between the BMS and the GxR-ONE may be a good idea, just in case.
Either way, the battery's voltage range is outside of the official spec of GxR-ONE so it's at our own risk.

How big is your case? You could use the GxR-ONE and a modded server PSU or any other 12v 500/600W brick inside the case, but leave the connector between the GxR-ONE and the brick somewhere accessible. In the house, you can just plug the brick to the GxR-ONE and a kettle lead into the brick. In the car, unplug the GxR-ONE from the internal PSU and plug it in directly to the BMS on the power pack.