Mobile(In Car) Computer Power Consumption question?

[bpgt64]

So I recently built a new system for my wife;

i5 2400(stock)
2 DDR3-1333 Dims
GTX 460 768MB
60GB SSD
1.5TB Storage Drive
Lian Li TU200 Case
Corsair TX 850W psu

Plugging all this into PSU calc shows me using about 335 W, not sure on the amps though. Probobly peaks around 1.5 ish. I will stress test tonight to find out.

But I want to put it in our Pontiac Vibe. In fact, I want to put it in the passenger side floorboard, plugged into the 120V jack. Setup a 20 inch monitor, and basically allow for someone to lay down in the back of this car, and be able to play computer games, while we drive all over creation this holiday season. Am I insane? Would this kill my car battery?

 

[ChristTheGreat]

Well, you would need a big battery and maybe a better Alternator, no?

it won't take 335w, since I did a test with my Kill-a-watt, myrig consume 100w at idle, 190w at full charge prime95, 260w with Furmark running, and 330w Prime95 + furmark

but, you have a 120v jack? I think you might have a 12v inverter to the 120v, no?

 

[bpgt64]

That sounds right. Though, I was considering picking up a 400w power inverter, that plugs into a cigarette outlet.

 

[bpgt64]

http://www.frys.com/product/5349598

like this?

 

[CJCerny]

Should work, as long as the inverter that they used puts out enough watts and amps. Unfortunately, finding the details on that will probably be difficult.

 

[bpgt64]

Well, this one I linked does like 300W Continuous, 600W maxed. I think that should work, and we've got Triple A if shit really hits the fan.

 

[ChristTheGreat]

Give a try, I think that is the best way to know if it works lol.

Where ya going to put the monitor?

 

[xvi]

Those inverters typically don't output true sine waves. I've heard that passive PFC power supplies don't play well with things like that. I'm pretty sure that Corsair PSU would be active, but it's still something to consider.

I've wondered about stuff like this too.

 

[bpgt64]

Give a try, I think that is the best way to know if it works lol.

Where ya going to put the monitor?

I am not sure HOW to show you, but google 2005 Pontiac Vive, you can fold down the front seat and it becomes a tv tray of sorts. Gonna put the Tower in the passenger side floorboard, and the Monitor on the Laptop/TV table.

Gonna be Movie/Skyrim time all the way to Ohio(from GA)...well trading off with my Wife. Who will spend her time watching Sisterhood of the traveling whiny girly movie.

 

[CJCerny]

My main fear would not be the power situation, but that desktop 1.5tb hard drive. Hit a mean pothole with that thing running and it's toast. It is not built for shocks like a laptop drive would be.

 

[bpgt64]

Well, see I am on the ropes about that. I haven't put the drive in yet, because it's currently an external drive. I may just leave the one SSD and add another 120 GB Drive. possibly...

 

[bpgt64]

This may sound insane, but I am considering putting this thing on a ABS UPS, in order to make the power to the Computer/Monitor somewhat un-interuptable. Would this remedy the difference between Modified Sine wave power, and Pure Sine Wave based power? I am assuming the difference has to do with the consistency of power flow between peaks and lows. Where a Power Supply would help deal with that. Also I was considering running power cables to the car battery, but most videos have the power run outside the car, whereas I am trying to use the car in motion, and draw power from the battery.

 

[slyfox2151]

i have to post this...



THIS IS THE COOLEST IDEA EVER!



sure you can get movies and tv in cars these days.... perhaps even consoles.... but this is a full blown PC!

 

[mlee49]

I think you'll be fine, but dont blame me when your car doesn't start and your broke down on the side of the road and cant play Crysis.

 

[Jstn7477]

Pulling over 100w from your cigarette lighter MAY KILL IT. I did so with my dad's DV8233cl (120w) in his 2002 Chevy Tahoe. Most are rated for 100w, and most are on the same 10 amp circuit as the radio/accessories, so you'll need some 8-10 gauge wire with an appropriate fuse between the battery and the inverter to bypass the weak electrical system. Even then, the Vibe probably only has an 80 amp alternator, and 350w/12v is 30 amps, so yeah, you may want to investigate.

My dad's cigarette lighter wiring shorted out, and my Camry clearly states 120w shared for both power outlets.

 

[Lazzer408]

330w from 12v source is 27.5 amps plus any efficiency losses.

I had a computer in the car years back. Hit plenty of potholes without killing the drive.

 

[John Doe]

Online PSU calculators are garbage, have a look at here.

http://www.guru3d.com/article/geforce-gtx-460-review/13

Guru3D peaked to 307W from the wall with a 460 - on an OC'ed i7 Nehalem with CCFL's, while running FurMark... I leave you the math.

 

[Lazzer408]

Online PSU calculators are garbage, have a look at here.

http://www.guru3d.com/article/geforce-gtx-460-review/13

Guru3D peaked to 307W from the wall with a 460 - on an OC'ed i7 Nehalem with CCFL's, while running FurMark... I leave you the math.

307w = 25.6amp@12v plus the eff. loss of the invertor and the psu.

 

[John Doe]

307w = 25.6amp@12v plus the eff. loss of the invertor and the psu.

Uhm, no. First off, amperage numbers don't matter as they equal to wattage at the end. And per-rail amps don't matter either since OCP set-points are always high. It's the wattage that you should go from. Read this.

http://www.overclock.net/t/880633/psu-amps-myth

With that out, that system is running FurMark, and is a pretty intensive setup. So you can take a 50-100W for just that alone. As well as some more from AC-DC transformation.

 

[Lazzer408]

Uhm, no. First off, amperage numbers don't matter as they equal to wattage at the end. And per-rail amps don't matter either since OCP set-points are always high. It's the wattage that you should go from. Read this.

http://www.overclock.net/t/880633/psu-amps-myth

With that out, that system is running FurMark, and is a pretty intensive setup. So you can take a 50-100W for just that alone. As well as some more from AC-DC transformation.

Um yeh. If the PSU requires 307w it's 307w from a 120v outlet. For a 12v to 120v power invertor to provide that 307w from a 12v source you have to add the eff. loss of the invertor to the equation. Say the invertor draws 400w from the car to produce the 307w the PSU is drawing... 400w/12v=33.3a from the car's electrical system. In that example, the invertor is using 7.7a more then required due to it's inefficiency.

And when does amps=watts? 307w at 120v is 2.56a. 307w from a 12v source is 25.58a.

Oh I see you edited your statement about watts. The only incorrect statement I may have made is the PSU in the calculation. Depending on where the load test was taken (psu input or output). If the load was taken at the PSU output (like it should be) then my statement stands true. If the load was taken at the PSU inlet (which isn't a proper load test) then you can leave out the PSU out of the calculation.

As far as rails. I haven't seen a power supply yet with more then one 12v rail even though they are advertised as having two. Internally they had one secondary used for the (single) 12v rail. I've been in quite a few PSUs. When my own PSUs go I repair them. I'd rather drop $.20 on a mosfet and $1 on a handfull of caps then $200 on a new supply.

 

[John Doe]

Um yeh. If the PSU requires 307w it's 307w from a 120v outlet. For a 12v to 120v power invertor to provide that 307w from a 12v source you have to add the eff. loss of the invertor to the equation. Say the invertor draws 400w from the car to produce the 307w the PSU is drawing... 400w/12v=33.3a from the car's electrical system. In that example, the invertor is using 7.7a more then required due to it's inefficiency.

And when does amps=watts? 307w at 120v is 2.56a. 307w from a 12v source is 25.58a.

Look, that's no way what I'm talking about. What I'm saying is, the guy's system pulls over 100W less than that setup. Their machine has CCFL's, an OC'ed i7, and is running FurMark. The guy has a very efficient setup and won't load that machine anywhere near that number realistically.

As far as rails. I haven't seen a power supply yet with more then one 12v rail even though they are advertised as having two. Internally they had one secondary used for the single 12v rail.

I'm not talking about that, I said OCP set-point. I was referring to virtual rails, not physical.

 

[Lazzer408]

Look, that's no way what I'm talking about. What I'm saying is, the guy's system pulls over 100W less than that setup. Their machine has CCFL's, an OC'ed i7, and is running FurMark. The guy has a very efficient setup and won't load that machine anywhere near that number realistically.



I'm not talking about that, I said OCP set-point. I was referring to virtual rails, not physical.

I didn't want to start an argument over his power requirements. I just chimed in to put him in the ballpark of what the invertor would be drawing from the vehicle. I used the 307w as an example. If it's 200w then 200/12=16.6a. It's more like 200/14.2=14.1a but I always calculate automotive voltage at 12 to account for losses in the wiring.

The OP stated "I was considering picking up a 400w power inverter, that plugs into a cigarette outlet."

Then Jstn7477 stated "Pulling over 100w from your cigarette lighter MAY KILL IT."

Well... Look at any of my examples and they will ALL kill it. That's the point I was trying to make rather then just say "The cig lighter won't work". Someone might actually learn something if I go on to state WHY it won't work.

 

[John Doe]

None of that has anything to do with what I posted. My point was entirely on about power consumption of such system, not plugging it to a car.

I just post it to give an idea on how efficient such system would be.

 

[1freedude]

The ups idea is a good one. When you start the car, it will shut ANY inverter down. The vdroop is crazy, like down to six...

I recommend mounting a 400 to 800 watt inverter in the engine bay and running an extension cord through the firewall. Safer and cheaper. Plug ups into extension cord, comp into ups, and monitor into built-in 120v. Get sound to the stereo.

 

[Completely Bonkers]

Do not attempt to run a power inverter >150W through the cigarette lighter. You need to wire directly to the battery.

For running >150W for long periods of time, you will need to UPGRADE YOUR CAR's alternator... or you will soon find that your car headlights will dim and when you come back to your parked car you will have a flat battery.

Try looking on websites that cover topics like pimp-your-ride and 500W soundsystems... and see what they have to say about alternators and power output and car battery requirements and reduced horsepower of car etc.