Hey guys, powering an MD64 lappy questions..

Someguitarist · 08-14-2007, 03:22 PM

I'm new to the forum... it's VERY cool and helpful stuff you guys have here.

I just read the Wiki on powering the systems. My problem here is that a DC-DC inverter is just too expensive. I figured I'd have to do the ghetto AC-DC-AC thing, and hope for the best. I have a few questions...

1) How bad is audio noise? If the converter is on one side of my car, and the lappy on the other, I'm not too concerned about the electric intereference, just the lack of voltage regulation...

2) I plan on just running a line out from the laptop to my car's head unit. It has a line-in. Do you think this would provide adequate sound?

3) I actually just bought a converter, but it seems as if each time I plug my laptop in it refuses to provide power (light turns yellow and beeps. I know it works because it can charge my phone) I was wondering if this was because my laptop draws (according to the spec page) close to 90 volts... is this just an inadequate converter? Is there another cheap way to provide power?

4) I'm actually interacting with my PC through voice commands with a mic coming through the steering wheel. It actually does really well even with the car going and music blaring. I want to see how well this works before I put more serious money into this.

Thanks guys and gals! Sorry for all the questions! I'm a poor college kid, so I can't invst in much, but it just seems like I have it all working more or less how I want it to minus the power...<br /><br />

DarquePervert · 08-14-2007, 06:16 PM

1 - If you follow good wiring techniques, you shouldn't have an issue with sound quality.
2 - Yes.
3 - I doubt your laptop draws 90v. 90w maybe. Power is not something you want to get on the cheap. You want it to be quality and you want it to be stable.
4 - No question to answer.

Someguitarist · 08-14-2007, 07:29 PM

Haha, yea, sorry, 4 really wasn't a question I guess... has anyone else tried using voice commands? And I noticed I left the A off of AMD... whoops again.

And yes, I did me 90 WATTS... man, I'm full of errors.

What is the best way and cheapest way for me to provide 90 watts if a cigarette lighter converting it to an outlet keeps conking out on me?

EDIT: Actually, lemme rephrase that... why would the converter not work for my laptop? Is the draw just too rediculously big? And could I simply get a BETTER converter, or is it because of my car's battery and the alternator and such?

pdloader · 08-15-2007, 09:00 AM

Quote: Originally Posted by Someguitarist

why would the converter not work for my laptop? Is the draw just too rediculously big? And could I simply get a BETTER converter, or is it because of my car's battery and the alternator and such?

90 W / 12 V = 7.5 Amps !!!!

Consuming 90W of power shouldn't be a problem for your battery and alternator. I'm guessing you converter is not designed for such a power consumptions.

Check the back of you converter, it should say how much power it can handle. for example it will say: "60W normal and 80W for 20 Minutes". For this example you can only withdraw 60W of power since taking 80W of power for more than 20 minutes would kill your converter.

Someguitarist · 08-15-2007, 09:53 AM

Hmm... the converter says 90-120 Watts... and... wait... here we go.

The laptop converter sas 100-240 Volts at 2.4 Amps... so does that mean I need a converter that can put out... 576 Watts? Good lord. Can I even find anything like that?

If I took my laptop apart and took out the video card, and the extra stick of RAM, would that save me a lot of power?

The car charger works when the laptop is off, but when I turn it on, it gives out...

pdloader · 08-15-2007, 10:07 AM

Quote: Originally Posted by Someguitarist

Hmm... the converter says 90-120 Watts... and... wait... here we go.

The laptop converter sas 100-240 Volts at 2.4 Amps... so does that mean I need a converter that can put out... 576 Watts? Good lord. Can I even find anything like that?

No..No... When it says 100-240 that's the input that your laptop's adapter can take in, not the output it gives to laptop. They make it in that range so you can use it in North America (110V) and in Europe and Asia (220V). To find out what is the voltage your laptop takes check the adapter to see what is the Output of it. That's the voltage your laptop needs. You can check your Laptop's Manual as well.

Keep in mind, My Pentium IV 2.8 GHz with 1 GIG ram and 256MB graphic card, 2 160GIG HDD and bunch of other stuff uses a 450W power supply

Hey, BTW, I've seen 700W converter as well but they can eat up a fully charged battery in 30 Minuets. (700/12=58 Amp)!!!

Someguitarist · 08-15-2007, 10:18 AM

Good lord. How much would these converters run me? Would I be better off just saving for a DC-Dc converter?

I'm in the process of retarding my computer right now. I've tried turning everything off in BIOS and hardware profile, but things like the CD player still have power... so...

I'm planning on running the entire thing off voice commands, so I'm thinking maybe if I pull out the CD driver, and maybe even the video card (if it'll start without a video card) to save some power... do you think this'll do anything, or should I just get a better converter?

Someguitarist · 08-15-2007, 10:35 AM

That actually worked, just disabling everything I didn't need under device manager. It charges now, but I kinda fear overheating and/or killing the alternator if it was pushing it that far to the limit...

I'm just going to get one of those programs that slows down the processor, just to save a bit more power, then I'll drive around with it going and see what happens I guess...

pdloader · 08-15-2007, 10:36 AM

Did you check the output of your laptop adapter? Mine says 22V and 4.9 Amp so it's 107.8W. If that's the same as your laptop, it's better to change your converter because when your laptop starts it always draws more current (Amps) than normal. You always want to be on the safe side so upgrade your converter with something that can produce at least 130-150w power.

As for going with DC-DC regulator, I'm not really sure (I'm a newbie in this matter).

Someguitarist · 08-15-2007, 10:45 AM

It's 18.5 at 4.9, so it's 90.65 W... so you just use and regular cigarette lighter converter too? What's the worst case scenario here? I just blow the converter? Would I hurt my alternator any by running this fairly constantly if it's going through the cigarette lighter and converter?

pdloader · 08-15-2007, 10:49 AM

Quote: Originally Posted by Someguitarist

It's 18.5 at 4.9, so it's 90.65 W... so you just use and regular cigarette lighter converter too? What's the worst case scenario here? I just blow the converter? Would I hurt my alternator any by running this fairly constantly if it's going through the cigarette lighter and converter?

No it won't hurt your alternator but you are running a risk of fire because the converter could get pretty hot if you run the laptop on it's full power constantly. hmmm.... let me see, no actually, the power converter has it's own fuse so it will shut off if there is too much power demand from your laptop.

Someguitarist · 08-15-2007, 11:01 AM

Good stuff. Well, I've been slowing it down mroe and more, and I figure if I keep the lid shut so the screen is off I should be good.

Anyways, thanks for the several replies, I've got to go drive a town over to get a new head unit that accepts Line In... so I'm gonna keep the lappy running the entire way and see what happens...

I'll update this with what happens later.

Thanks for the so many replies

Someguitarist · 08-15-2007, 11:39 AM

After going around the block several times it blew again... I'm guessing I just need a better converter... I'll hafta look around for one... ;(

pdloader · 08-15-2007, 12:21 PM

Hey i found 150-300watt Dc to Ac that you can order online....

go to this link: http://www.pplmotorhomes.com/parts/r...ar-adapter.htm

Hope it helps...

Someguitarist · 08-15-2007, 03:53 PM

Hmm, thank you very much. I'm gonna hafta go down to Wallmart and see if I can't find one that I don't have to get mailed, but that's the next choice. Thanks for all your help!