[SOLVED] Directly powering a PC with a 12v battery. Skipping the PSU

[Thwwack]

Hello folks.

I am hoping for some advice.

I'm about to embark on a long vanlife adventure, and want to take my beloved desktop PC with me.

From what I understand, PC PSUs output 12v. I'm thinking I'll just directly power the PC with my house battery in the van, skipping the PSU.

Does anyone know of any problems I may encounter doing this? The only problem I can imagine would occur when the battery voltage starts to drop, but surely there is some software I can install to make the PC recognize this, and shut components down (like in a laptop).

The supply power will be fused.

Any problem identifications and software recommendations are greatly appreciated.

Cheers
Emile

 

[madmatt30]

Problems??

A broken pc and a van fire I would say.

Unless you're an electronics wizard (and if you're asking these questions then you're not) this isn't viable.

Modern pc psu's have many built in safety protections and don't just output 12v.

3.5v and 5v rails are also required for the majority of smaller components on the board

That big 20+4 pin that plugs into a motherboard carries all these voltages on different pins.

Unless you're talking about the mini type of pc which has a 12v pico connector then what you're suggesting is practically impossible.

 

[mdd1963]

best to just take along a cigarette lighter -style DC to AC power converter.....

But, just get a laptop instead, you really don't want to be running 200-400 watt loads for very long from your vehicle's battery....

 

[TerryLaze]

You can get an upscaler that will turn 12V from your car battery and turn it into a normal wall socket so you can plug in your PC.
Good luck to you while you get stranded on the side of the road all the time due to dead battery.
This is the first thing I found when I googled I have no idea which brand is good or if this one is any good.

https://www.amazon.com/Foval-Power-Inverter-Converter-Charger/dp/B07SVDH7CT/

 

[King Dranzer]

You will just be Making things more Complicated. Why don't you simply connect PSU to car. I mean even then it will need little work around but is much simpler thing to do. Depending on the Power consumption of PC if it is 400W or more and if you have small capacity battery with weak alternator you may need to upgrade the alternator and battery which adds up to cost and process but that is a must.

You said you have a van. Usually Vans and Trucks are fit with good capacity battery and alternator which would be fine to support PC running off of it. But still would recommend to check into it.

 

[Thwwack]

Thanks for all the quick replies.

Of course, running an inverter for mains power is an option, but you loose power efficiency with each conversion. 12v battery ->inverter->PSU->Motherboard is a substantial loss. Each translation between 10-30ish percent.

I have a laptop. but I hate it. And my Desktop is decked out with a lot of data and is a platform that if I take with me, would allow for different kinds of work.

@madmatt30 Some great info there, thank you. Looks like it's time to get my multimeter out and check these pins. Was hoping it was going to be a simple "yes, just plug it in - from you folks". I'm experienced with electronics, but it's always nice to get save time by doing research online first.

You seem to be well versed on this topic, can you point me to a resource that will tell me which components in my system require 3.5v, 5v, and which require 12v, and give specifications for power requirements for each, by chance?

 

[Thwwack]

P.S. My motherboard is a Maximus Vi Hero.

 

[King Dranzer]

Thanks for all the quick replies.

Of course, running an inverter for mains power is an option, but you loose power efficiency with each conversion. 12v battery ->inverter->PSU->Motherboard is a substantial loss. Each translation between 10-30ish percent.

I have a laptop. but I hate it. And my Desktop is decked out with a lot of data and is a platform that if I take with me, would allow for different kinds of work.

@madmatt30 Some great info there, thank you. Looks like it's time to get my multimeter out and check these pins. Was hoping it was going to be a simple "yes, just plug it in - from you folks". I'm experienced with electronics, but it's always nice to get save time by doing research online first.

You seem to be well versed on this topic, can you point me to a resource that will tell me which components in my system require 3.5v, 5v, and which require 12v, and give specifications for power requirements for each, by chance?

As I said it is fine for up to 400W even or Regular Small cars. But as you said you have Van(What is the Make and Model) it should support even greater Wattage like 600W.

 

[Thwwack]

As I said it is fine for up to 400W even or Regular Small cars. But as you said you have Van(What is the Make and Model) it should support even greater Wattage like 600W.

Thanks mate, the power consumption is not really a concern. I have solid infrastructure there.

In saying that, I know I won't be able to run it forever while I'm on the road without access to mains power, and I simply wouldn't take it with me if at all if I cannot solve the conversion inefficiencies by skipping the inverter and PSU. I think that would be too much waste to be practical.

 

[USAFRet]

Of course, running an inverter for mains power is an option, but you loose power efficiency with each conversion. 12v battery ->inverter->PSU->Motherboard is a substantial loss. Each translation between 10-30ish percent.

2 E's:

Efficiency or Explosion

You would have to reproduce all the power distribution of a PSU. In effect, building your own PSU.
But without the research and engineering...

 

[Thwwack]

P.S. I realised I didn't answer your question. It's a toyota hiace with 120AH house battery and solar DC-DC charger. Jap only model with a HUGE alternator.

 

[Thwwack]

2 E's:

Efficiency or Explosion

You would have to reproduce all the power distribution of a PSU. In effect, building your own PSU.
But without the research and engineering...

I'm sensing a tone of caution coming from the board... Can I ask, what exactly do you expect to be the problem? Do the voltages need to be strictly regulated for Motherboards? Any idea of what sort of variance can be allowed?

 

[USAFRet]

A "tone of caution"?

No, more like an outright -Do Not Do This

The PSU delivers more than just a simple 12v.
Your storage devices, for instance....need 12v, 5v, and 3.3v.
The PSU splits all that out internally.

In addition to the protection circuitry, for when something IS out of bounds.


Embarking on this would be literally building your own brand PSU.
You can't just plug a 12v battery straight into the motherboard.

 

[King Dranzer]

Thanks mate, the power consumption is not really a concern. I have solid infrastructure there.

In saying that, I know I won't be able to run it forever while I'm on the road without access to mains power, and I simply wouldn't take it with me if at all if I cannot solve the conversion inefficiencies by skipping the inverter and PSU. I think that would be too much waste to be practical.

That is a better way than trying to find a purely efficient and complicated way. Literally to get it working the way you want it is extremely complicated and won't be as practical.

Edit: Look up USAFRet gave you good explanation of how complicated PSU Functionality is.

 

[Thwwack]

A "tone of caution"?

No, more like an outright -Do Not Do This

The PSU delivers more than just a simple 12v.
Your storage devices, for instance....need 12v, 5v, and 3.3v.
The PSU splits all that out internally.

In addition to the protection circuitry, for when something IS out of bounds.


Embarking on this would be literally building your own brand PSU.
You can't just plug a 12v battery straight into the motherboard.

I understand what you're saying. And very much appreciate your advice.

In saying that, I'm up for building a system to convert 12v to 5 and 3.3v, I'd like to know if anyone knows what kind of variance in voltage each circuit will allow to remain operational, and typically how sensitive each system tends to be. Then I can determine if the project is viable or not. Perhaps I need to move this to an Electrical Engineering forum.

 

[COLGeek]

I understand what you're saying. And very much appreciate your advice.

In saying that, I'm up for building a system to convert 12v to 5 and 3.3v, I'd like to know if anyone knows what kind of variance in voltage each circuit will allow to remain operational, how typically how sensitive each system tends to be. Then I can determine if the project is viable or not. Perhaps I need to move this to an Electrical Engineering forum.

You need something like one of these devices:

Best RV Power Converter Reviewed in 2024 - Where You Make It

Your RV's electrical system may not be the most exciting thing to learn about, but it is important to understand nonetheless. The RV power converter is a crucial component that is often confused with the inverter. It is essential to keep your RV powered, whether it is plugged in or disconnected...

whereyoumakeit.com

You also want a dedicated dedicated battery (not the one that starts the engine) to store power via your solar panels.

Connecting directly, as previously discussed, is the path to heartache.

 

[USAFRet]

I understand what you're saying. And very much appreciate your advice.

In saying that, I'm up for building a system to convert 12v to 5 and 3.3v, I'd like to know if anyone knows what kind of variance in voltage each circuit will allow to remain operational, how typically how sensitive each system tends to be. Then I can determine if the project is viable or not. Perhaps I need to move this to an Electrical Engineering forum.

Can you build your own "power supply"?
Well, it can be done. I don't know if YOU can do it, but, in theory, it could be done.

Buy a current PSU.
Obtain the engineering and design docs.
Recreate it, in a different box.
Poof...your own system.

Which works exactly as the one you bought does.

(try this with throwaway computer parts. Don't use your good PC on the first (or tenth) attempt)

 

[USAFRet]

Also, moving this to Power Supplies forum...

 

[Thwwack]

You need something like one of these devices:

Best RV Power Converter Reviewed in 2024 - Where You Make It

Your RV's electrical system may not be the most exciting thing to learn about, but it is important to understand nonetheless. The RV power converter is a crucial component that is often confused with the inverter. It is essential to keep your RV powered, whether it is plugged in or disconnected...

whereyoumakeit.com

You also want a dedicated dedicated battery (not the one that starts the engine) to store power via your solar panels.

Connecting directly, as previously discussed, is the path to heartache.

Thanks for your reply, I have all of this already. I'm just curious about an alternative solution.

Can you build your own "power supply"?
Well, it can be done. I don't know if YOU can do it, but, in theory, it could be done.

Buy a current PSU.
Obtain the engineering and design docs.
Recreate it, in a different box.
Poof...your own system.

Which works exactly as the one you bought does.

(try this with throwaway computer parts. Don't use your good PC on the first attempt)

Okay, Okay. Thanks for your response. I think this is much simpler than you imagine, but I'm happy to be proven wrong. I'll give it a go and get back to you with news of the results.

 

[COLGeek]

...just keep in mind that your vehicle charges itself at approximately 13.8v.

If you already have the components indicated above, you have all you need. I would suggest adding a small UPS to act as a buffer for power variances between your PC and power source.

 

[DSzymborski]

Thanks for your reply, I have all of this already. I'm just curious about an alternative solution.


Okay, Okay. Thanks for your response. I think this is much simpler than you imagine, but I'm happy to be proven wrong. I'll give it a go and get back to you with news of the results.

Well, at least then you'll have an excuse to purchase a new PC...

 

[USAFRet]

I'm just curious about an alternative solution

http://www.bee-link.com/portal.php?mod=view&aid=146

 

[Thwwack]

why dont you for the sake of complexity leave your beloved desktop at
home and take a laptop ..use a dc to ac converter 12v to 240ac ..then just
keep your laptop charged as needed
a circuit that will deliver all the required voltages to
run a desktop from a 12v battery would be impracticable since you
need +/- rails at 12v ..so you would need 2 batteries probably
it would cost a small fortune to boot

ps would you get the current requirements using a dc to ac converter
(12v/240vac) to run a switching ATX psu ???? and for how long
you need to do the maths

I'll likely leave it home, but it's an interesting idea, and could be viable if you skip the PSU and power the components directly with DC-DC converters. The biggest question, which looks like I'll have to answer through trial and error, is how consistent the voltage needs to be, and how much power output is required for each voltage. If anyone has experience with this and can answer these questions, please let me know.

 

[USAFRet]

If anyone has experience with this and can answer these questions, please let me know.

@jonnyguru - Your expertise and advice requested, sir.

 

[King Dranzer]

You need something like one of these devices:

Best RV Power Converter Reviewed in 2024 - Where You Make It

Your RV's electrical system may not be the most exciting thing to learn about, but it is important to understand nonetheless. The RV power converter is a crucial component that is often confused with the inverter. It is essential to keep your RV powered, whether it is plugged in or disconnected...

whereyoumakeit.com

You also want a dedicated dedicated battery (not the one that starts the engine) to store power via your solar panels.

Connecting directly, as previously discussed, is the path to heartache.

I don't think he has any intention of going Solar Power Route.

If OP takes Solar Power Route then he wouldn't have to spend all the time and resources trying to work it other way round.

It is on bit high out-right expenditure. But if he is regular traveler it is completely worth it.