# Power options for car PC???



## LGHT_ (Jan 12, 2011)

Fairly new to Car pc's and have been reading a lot, but stuck on what way to go with for power.

Right now I have a Double Din, EQ, crossover hooked up to 3 amps 2 subs and 2 sets of 6.5 separates . The largest amp is 1500 watts for my subs then I have a 4 channel 600 watt for the front set of 6.5 separates then a 400 watt amp for a rear set of 6.5 separates. The vehicle is a Yukon and I've already upgraded the battery to a yellow top AND have 0 awg from the batter to my distribution block for the amps. As of now my power seems fine, but I do have the occasional light dim when at full power during heavy bass tracks at night.

I have read most people use M4 or Opus and keep the load under 250 watts, but I just ready a review on an soundblaster external xfi and the guys has his carputer in the back of the truck connected via a 1000 watt power inverter to a cigerrette light connection and is using a standard 400 watt PSU on the PC.

Since I already have a huge draw on my current battery should I consider a 2nd batter, upgraded alternator, or both?

Also what are the advantages of running the pc from a power inverter? Since the yukon already has power in the back truck via a cigarette lighter connection if I used that it would allow me to connect an inverter and avoid having to redo my center console to mount the pc there.


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## nomed (May 17, 2008)

LGHT_ said:


> Fairly new to Car pc's and have been reading a lot, but stuck on what way to go with for power.
> 
> Right now I have a Double Din, EQ, crossover hooked up to 3 amps 2 subs and 2 sets of 6.5 separates . The largest amp is 1500 watts for my subs then I have a 4 channel 600 watt for the front set of 6.5 separates then a 400 watt amp for a rear set of 6.5 separates. The vehicle is a Yukon and I've already upgraded the battery to a yellow top AND have 0 awg from the batter to my distribution block for the amps. As of now my power seems fine, but I do have the occasional light dim when at full power during heavy bass tracks at night.
> 
> ...


I use M4 power supply in my config and I have clamped about 9A constant draw from battery on idle.

You better use 12V carpc psu instead converting DC voltage to AC for standard psu.


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## LGHT_ (Jan 12, 2011)

nomed said:


> I use M4 power supply in my config and I have clamped about 9A constant draw from battery on idle.
> 
> You better use 12V carpc psu instead converting DC voltage to AC for standard psu.


I don't mind using a 12v PSU like the M4, but the problem with that is i'm limiting myself to only 220 watts and I'm afraid I would run out of power. Is there in disadvantages of using the inverter? I just prefer not to limit myself on possible expansions if I can avoid it.


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## audiovibe (Nov 16, 2007)

If you are scared of limiting your self you could always run dual automotive power supplies. This is how my last install was, I had dual M2s. One was for the MB, processor, and other on-board stuff. The second was for HDD, SSD, monitor, amp turn-on, and maybe a couple other things. To get the second power supply to fire you just need to combine the two green sync wires and the grounds.


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## felix509 (Dec 17, 2006)

You might want to check how many Watts that cigarette lighter is good for.....

If the cigarette lighter in your car is rated at 10 AMPS you will only be able to use the inverter up to 120 watts, 15 Amps will allow you to use it up to 180 watts.

So yeah, 1000W inverter plugged into the rear cig lighter is not gonna happen...

You could get a decent inverter with lugs and run 8 guage, or 4 guage wire to it..


Inverters are inefficient, hence the need of the heat-sink, the lost energy produces the heat.. they don't have all the fun stuff Made for Car power supplies have, like auto on, remote out, hibernate on key off, lots of options...

_One comment on power supplies. I run a Toshiba QOSMIO Gaming laptop.

i7 Quad core processor, 3D graphics form 1.5 GB NVIDIA card, 8GB RAM, 2 hard drives, WIFI and Bluetooth running full time, and a super bright 17" display.

The power supply is *180W*, and besides running the machine, charges the battery.._


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## Miniboom (Jul 15, 2010)

I have a mini-laptop (Asus EEE, 10-inch) and its power supply has an output rating of 19VDC, 1.58A. Or roughly 30 watts.

The input rating says (I live in Europe) 230V, 1A, though I hardly think that small AC/DC-converter can ever pull 230 watts from the wall socket.

I think (hope) that computer can run fine from a very small 150W inverter for the lighter socket. 

Don't think I'd use "regular" inverters for much larger PSU's than this, anyway.


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## MarkZ (Dec 5, 2005)

felix509 said:


> _One comment on power supplies. I run a Toshiba QOSMIO Gaming laptop.
> 
> i7 Quad core processor, 3D graphics form 1.5 GB NVIDIA card, 8GB RAM, 2 hard drives, WIFI and Bluetooth running full time, and a super bright 17" display.
> 
> The power supply is *180W*, and besides running the machine, charges the battery.._


You're probably the only gamer I've ever seen post something with common sense. 

The need for high power supplies for most computing applications is a MYTH. PCs have gone in that direction, not because the components need more power, but because higher numbers = more sales. Computer aficionados insist on using gigantic power supplies because they're nerds who live for that ****.  

My laptop power adapter is rated for 1.5A @110v. That means that the maximum rated power consumption is about 150w. This is max. This doesn't include losses in the power transformer, and it doesn't include the fact that this is a maximum rating, not an actual draw. My laptop probably realistically consumes less than 100w.

Granted, people (for whatever unknown reason to me...) insist on using inefficient CPUs in their computers. Fine. Add 50w for that. You're still well below any reasonable limit.

USB peripherals tend to draw minimal power. The USB ports will shut down if you draw substantially more than 500mA @5v (=2.5w).


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## LGHT_ (Jan 12, 2011)

Ok I think I will just go with the M4 and worse case scenerio upgrade to a 2nd power supply as 2nd option. I don't think I will run out of power, but I have a long list of things I want to run on the carputer such as OBD, HD radio, GPS, VOX, Rearview cameras, bluetooth, XM, mkv capable video card and a maybe even a wet bar.


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## nomed (May 17, 2008)

In other words, unless you planning to install gaming rig with quad SLI configuration, M4ATX or 320W opus will be sufficient for any config.


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## LGHT_ (Jan 12, 2011)

nomed said:


> In other words, unless you planning to install gaming rig with quad SLI configuration, M4ATX or 320W opus will be sufficient for any config.


I have my 360 in the back to game with so I won't need to game from the PC.


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## LGHT_ (Jan 12, 2011)

victoriaphageB said:


> Thanks for the post. I am having power options with my car.


Well i'm still not out of the woods just yet. I may have to put in a 2nd battery or at least a bigger alt since I also have a 1500, 800, 600 watt amps that are all pulling from that 1 battery. Although it's not a huge problem now the lights do dim when the sounds up a night so I may just need to do something once I put the computer and all my devices in.


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## MarkZ (Dec 5, 2005)

I'd be surprised if the computer made your dimming worse. Your amps are drawing a lot more current than the computer will, and they're drawing it in spurts which tends to be more taxing on the battery and alternator than constant draw.

Also don't worry too much about voltage spikes and dips getting to your computer. Whichever power supply you choose for your computer will (should) have good filtering in it.


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## ninja6o4 (Feb 13, 2012)

MarkZ said:


> You're probably the only gamer I've ever seen post something with common sense.
> 
> The need for high power supplies for most computing applications is a MYTH. PCs have gone in that direction, not because the components need more power, but because higher numbers = more sales. Computer aficionados insist on using gigantic power supplies because they're nerds who live for that ****.
> 
> ...


You are right in some regard - PC power requirements are definitely overstated to some extent, and the average person buys far more than they need.

However, you were comparing a laptop's power consumption with a full desktop PC. Laptops are designed to conserve as much power as possible, even gaming laptops. And with such limited power available to begin with, you will hit a limit somewhere (either with heat dissipation or performance), and the laptop will not let you go past that point. I'm being very broad in this statement, because there are always ways to do things you aren't meant to do 

On a PC, it may not care and will let itself go until it goes into thermal protection or blows the PSU. That is why people generally overspec the PSU on desktops (for the 0.0001% of the time your PC could be at absolute 100% load.) This pretty well never happens for sustained periods unless you are running folding/cancer research apps.

My rig is a full PC, i7-2600K overclocked to 4.5, 16GB, SSD+HDD, 2x GF570 SLI, and discrete sound/network cards. At idle, I am certain I could get away with a 250w PSU or less. While gaming I would need around 400-500w. At max load, most likely 600-700w. So I bought an 800w, because I am spec'ing for worst case scenario, which we all do (or should do) with our cars.

Anyway, for the OP - Don't run an inverter, get a CarPC PSU like the M4 or Opus, for the same reasons already mentioned: inefficient compared to PSU, and PSU has specific features designed for car use (such as timed shutdown events, power on accessory, maintain stable voltage through crank, etc.) An inverter will have none of this and waste more power than you already seem to have.

My CarPC runs on an M4 and it is powering a mini-itx Zotac board with an E5200 cpu and SSD+HDD. It's powering USB based wifi, GPS, radio, external 2.5 drive (only while loading more stuff), dvd drive, RF for kb/mouse, and it is solid. The only thing I would change is I'd add a hidden rocker switch tied to the acc/remote wire for short trips to allow me to skip the PC startup/shutdown sequence.


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## MarkZ (Dec 5, 2005)

But have you measured current draw? What's so dynamic?


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## ninja6o4 (Feb 13, 2012)

Sorry, I haven't measured amp draw on the carpc, I'm not running anything else of significant draw so I never bothered.. The dynamic portion would be how much the car is providing.


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## MarkZ (Dec 5, 2005)

No, I meant in the home rig. I'm curious what's causing so much draw to the point where you go from being fine with 250w to needing 800w. That's a considerable difference.


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## ninja6o4 (Feb 13, 2012)

oh, well at idle, PCs draw very little power (as you know), and the 2 video cards would be drawing next to nothing when idle (maybe 50w each). At load they are rated at 250w each . Combine that with an overclocked cpu at load (another 170w), + say 30w for the other components, you're pretty much at 700w. Now you never want to let a PSU run at 100% load, so you have to 1 step higher to 800.. which is still 87% load.

This is still theoretical, because I don't do folding/stress testing 24/7, but I wouldn't want to spec a PSU based on my usual requirements just because things can go wrong. Even a momentary spike (say a game locking up and running all processes full bore) on a lower capacity PSU could be enough to cook it. Same reasoning for say turbocharging cars or selecting the right amp. You need enough fuel or power for worst case scenario, even if you would almost never need it..

I'm not saying that I know anything with any amount of measured accuracy, but 10+ years in IT and seeing more than my share of blown PSUs that fry other components on the way out has convinced me that a quality PSU spec'd properly is the way go. And yes, I have seen sparks/fire shooting out of them before  At least twice that I can recall offhand.

I tried to find an article I read a while back that tested loads in various states, but this is similar:
http://www.tomshardware.com/reviews/power-supply-psu-review,2916-11.html

The scenario is similar to mine except it is a bigger video card, and only 1 of them. I'm not sure what the draw on a 1x GTX580 vs 2x GTX570 is, but you get an idea of how much draw is theoretically possible..


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## MarkZ (Dec 5, 2005)

I'm curious how much performance gain you're achieving with such high power consumption components.

[Again, not that this has anything to do with car PCs  ]


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## ninja6o4 (Feb 13, 2012)

MarkZ said:


> I'm curious how much performance gain you're achieving with such high power consumption components.
> 
> [Again, not that this has anything to do with car PCs  ]


lol, we are threadjacking a bit. Sorry OP!

Like anything else, your ROI goes down the more $ you spend. It's all the same: cars, audio, computer, TVs.. I live in the computer world and spend a lot of my time gaming, so I want to have the best experience I can afford. Others feel the same for cars or audio or whatever (or all, if you're rich)

I can't really specify an exact gain vs power consumption, there are so many factors involved and different benchmarks you can compare against that we'd be better off discussing this in a PC enthusiast/gaming forum. Basically, I built this rig with the idea that I could run Battlefield 3 at maximum detail at 1920x1200 (24" screen), or at least good/high quality detail at 5760x1200 (3x 24" screens multimonitor mode) if I went down this path.

Sadly, it's not fast enough for my personal needs to enjoy the game at that detail..  BF3 has a lovely mode called "Ultra" that pretty much crushes my PC. Now if I could find a buyer for my 570's and upgrade to 580's......


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## DLO13 (Oct 24, 2010)

MarkZ said:


> You're probably the only gamer I've ever seen post something with common sense.
> 
> The need for high power supplies for most computing applications is a MYTH. PCs have gone in that direction, not because the components need more power, but because higher numbers = more sales. Computer aficionados insist on using gigantic power supplies because they're nerds who live for that ****.
> 
> ...


High end graphics cards require large power supplies. I dont care how much you think you know, but if you have ever used a high end graphics card and a PSU under 500Watts u will start to see your SATA devices cut out. Optical drives are usually the first to go.

Ur posting 0 facts and i doubt you really have much experience with true hardware. 

The industry is actually going towards LOW power consumption for the most part, video cards are the exception. The intel core 2 duo e6300 was the most amazingly energy efficient CPU around. The sandy bridge processors are even better. People buy large powers supplies and stability and over clocking. Rails on a psu are also very important.


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## MarkZ (Dec 5, 2005)

DLO13 said:


> High end graphics cards require large power supplies. I dont care how much you think you know, but if you have ever used a high end graphics card and a PSU under 500Watts u will start to see your SATA devices cut out. Optical drives are usually the first to go.
> 
> Ur posting 0 facts and i doubt you really have much experience with true hardware.


I said "most computing applications" and was sure to exclude gaming. Sorry to get you all agitated, but read first next time.


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## DLO13 (Oct 24, 2010)

MarkZ said:


> I said "most computing applications" and was sure to exclude gaming. Sorry to get you all agitated, but read first next time.


Well, you mentioned a "gamer".


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## MarkZ (Dec 5, 2005)

Yes, I used the word gamer. You're on the right track.


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## LGHT_ (Jan 12, 2011)

ninja6o4 said:


> lol, we are threadjacking a bit. Sorry OP!


No worries at all i'm enjoying the debate. I have a list of select clients that have endless amounts of $$$$ to dedicate to their home offices that I build and support custom pc's for from time to time. Sometimes i'll build a HTPC and i've even built a few gaming rigs. I ALWAYS lean toward buying a PSU that is probably twice what they need because I've learned to allow room for growth for things like home automation and controls and DVR upgrades.


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## ninja6o4 (Feb 13, 2012)

LGHT_ said:


> Ok I think I will just go with the M4 and worse case scenerio upgrade to a 2nd power supply as 2nd option. I don't think I will run out of power, but I have a long list of things I want to run on the carputer such as OBD, HD radio, GPS, VOX, Rearview cameras, bluetooth, XM, mkv capable video card and a maybe even a wet bar.


I read your post again here, and most of these features are external and very low power consumption (ie. USB powered). My HD Radio and cameras were powered externally (not via PSU) so that wasn't a problem.

Most likely any CarPC sized mobo these days now have built in HD Video decoding capabilities, so don't worry about a discrete card doing this.

You could also hook it all up and see how it handles it - if the load on the USB rail is too much, you can get a USB hub that accepts external power and wire in additional power directly to that hub.

Wet bar .. Well.. no comment.


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## LGHT_ (Jan 12, 2011)

ninja6o4 said:


> I read your post again here, and most of these features are external and very low power consumption (ie. USB powered). My HD Radio and cameras were powered externally (not via PSU) so that wasn't a problem.
> 
> Most likely any CarPC sized mobo these days now have built in HD Video decoding capabilities, so don't worry about a discrete card doing this.
> 
> ...


Yeah I was thinking about that as well as it does seem most of the offerings I need are USB powered which will draw a very minimal load. I do know I will need some type of USB hub for sure. 

Still haven't figured out what motherboard yet. Since I'm trying to make use of boxes and boxes or old cpu's and ram i'm trying to find a micro atx board to go with a Intel 2.4 Q6600 Core 2 Quad CPU L72A903 I had laying around. 

I figured I could OC it to a full 3.0 and just get a nice cooler for it, but haven't been able to find a board with integrated .h264 video support and an HDMI connection. I don't really need .h264 support, but since I have a HUGE library of movies it would be nice to load a few for long trips ya know.


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## MarkZ (Dec 5, 2005)

I'm still confused. Why OC it? In the car, heat is the biggest thing you have to deal with, so why introduce that problem for additional performance that you won't need for this particular application? The decision-making here seems odd. You're being more like Tim the Toolman Taylor than Al. 

Re: h.264 support, virtually anything will play back 1080p h.264. I just bought a 700 MHz machine that will do it on the onboard GPU.  And it has HDMI. I don't think you need dedicated h.264 support... it just needs to be able to handle OpenGL rendering, which they all do now. You just need to make sure you're using the right player.


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## ninja6o4 (Feb 13, 2012)

LGHT_ said:


> Yeah I was thinking about that as well as it does seem most of the offerings I need are USB powered which will draw a very minimal load. I do know I will need some type of USB hub for sure.
> 
> Still haven't figured out what motherboard yet. Since I'm trying to make use of boxes and boxes or old cpu's and ram i'm trying to find a micro atx board to go with a Intel 2.4 Q6600 Core 2 Quad CPU L72A903 I had laying around.
> 
> I figured I could OC it to a full 3.0 and just get a nice cooler for it, but haven't been able to find a board with integrated .h264 video support and an HDMI connection. I don't really need .h264 support, but since I have a HUGE library of movies it would be nice to load a few for long trips ya know.


You won't find any LGA775 based mobo with built in HDMI or h264 hw decoder still available to buy new today. Both of those technologies did not get popular until after LGA775 was introduced, and LGA775 is now a tech dead end.

This is the mobo I am using in mine: ZOTAC GeForce 9300-ITX [GF9300-I-E]

It's discontinued now, but the onboard GF9300 had SOME h264 capability, but enough so that my E5200 downclocked to 1.6 was able to handle 1080p mkv playback no problem.


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## UMD_Jesse (Apr 26, 2012)

Im running an Asus e35m1-m pro mobo and have no complaints. They have a mini-itx version on the same board if you dont need the pci slots. Also for your initial power supply questions, why not use the m4 atx? It has more than enough juice to run a car pc. You dont need any high end graphics or serious processor power cause the screens are so small with limited resolution. But with your large sound system Id definitley add a larger alternator.


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