A question about running my laptop/speakers from an ac/dc inverter, please help!

[chasem]

Im taking a road trip tommorow morning, and i need an ac/dc thing for my car for my laptop. i then figured that i could bring some better speakers too. All i got around are these logitech z560. From what i understand you cant draw more than 140w from the cig lighter, the laptop is max 60 watt power supply, and it will have a full battery. If i refrain from turning the bass up loud or turning the speakers up more than halfway, what are the odds i could get it to work. I know the logitechs are 400w power OUTPUT, but i have a hard time beiliving that it draws a constant 400w.
Thanks for you help!


edit: Inverter in question

 

[Heisenberg]

I would check the max power rating on the inverter as it may be lower than 140W. Then it would limit how much current you could draw. And no, I doubt the Z560's draw 400W all the time. See if you can find a RMS power rating. That'll be much closer to what they actually put out.

 

[chasem]

it says the rms rating is 400w, but i have a real hard time beilive it pulls as much as a small microwave.
The invertor can do 140max it has a 15a 250v Slo-Blo fuse on it, so i guess thats how much it can pull... right?

 

[Savij]

You could do it the easy way and use your car's speakers...all you need is the a cassette adapter.

 

[chasem]

i dont have a cassette player, just cd player

 

[Savij]

Ok, then get one of the ones that transmits via FM radio

 

[Heisenberg]

Originally posted by: chasem
it says the rms rating is 400w, but i have a real hard time beilive it pulls as much as a small microwave.
The invertor can do 140max it has a 15a 250v Slo-Blo fuse on it, so i guess thats how much it can pull... right?

400W does seem kind of high, but I don't know for sure. The one sure way to know is to hook it up and try it. If the fuse blows in the inverter, get yourself a pair of headphones.

 

[Savij]

Oh, and I blew a fuse with just my laptop and my pda plugged into a single inverter.

 

[chasem]

what wattage inverter?


where do i get one that transmits radio?
and it has to be local (ie best buy staples, compusa, walmart, radio shack), becuase im leaving tommorow

 

[cressida]

Originally posted by: chasem
it says the rms rating is 400w, but i have a real hard time beilive it pulls as much as a small microwave.
The invertor can do 140max it has a 15a 250v Slo-Blo fuse on it, so i guess thats how much it can pull... right?

rms value of 400w? That means it will have a peak of about 560 watts, yikes.

 

[chasem]

but honesty, do you think it constantly draws 400 watts?

but it also says 400w OUTPUT, and ya know how speaker companies kinda skew their wattage to attract the consumer.

 

[cressida]

Well if the specs are right, then yes it will draw about 400w, more or less.

 

[Heisenberg]

Originally posted by: chasem
but honesty, do you think it constantly draws 400 watts?

but it also says 400w OUTPUT, and ya know how speaker companies kinda skew their wattage to attract the consumer.

Yeah, those numbers sound a little suspect to me. Plus, there's more than one way to even define RMS power (well, one right way and one not-so-right way), so which definition they're using would make a difference. Like I said, plug it in and try it. I doubt anything other than the fuse blowing will happen.

 

[Thoreau]

Originally posted by: Heisenberg

Originally posted by: chasem
it says the rms rating is 400w, but i have a real hard time beilive it pulls as much as a small microwave.
The invertor can do 140max it has a 15a 250v Slo-Blo fuse on it, so i guess thats how much it can pull... right?

400W does seem kind of high, but I don't know for sure. The one sure way to know is to hook it up and try it. If the fuse blows in the inverter, get yourself a pair of headphones.

i would be more worried about the car's fuse blowing for the cigarette lighter outlets

 

[Thoreau]

Originally posted by: chasem
but honesty, do you think it constantly draws 400 watts?

but it also says 400w OUTPUT, and ya know how speaker companies kinda skew their wattage to attract the consumer.

let's just pretend that logitech is a bold-faced liar and double the numbers for those speakers. Thats still 200 watts, way more than a car inverter can handle. YOu can pick up one of those FM transmitters for something like $20 at Fry's or BestBuy (i got mine at Fry's) and use that, altho it will also require a cigarette lighter plug to use (might need a splitter then)

 

[Heisenberg]

Originally posted by: Thoreau

Originally posted by: Heisenberg

Originally posted by: chasem
it says the rms rating is 400w, but i have a real hard time beilive it pulls as much as a small microwave.
The invertor can do 140max it has a 15a 250v Slo-Blo fuse on it, so i guess thats how much it can pull... right?

400W does seem kind of high, but I don't know for sure. The one sure way to know is to hook it up and try it. If the fuse blows in the inverter, get yourself a pair of headphones.

i would be more worried about the car's fuse blowing for the cigarette lighter outlets

The inverter's are usually fused below the outlet. I've overloaded inverter's a few times (don't ask) and the inverter fuse always blew first. Even if the car fuse did blow, the likelyhood of any damage is pretty low.

 

[Savij]

Originally posted by: chasem
what wattage inverter?


where do i get one that transmits radio?
and it has to be local (ie best buy staples, compusa, walmart, radio shack), becuase im leaving tommorow

My inverter is 75watts, but I was trying a laptop and a pda, not a laptop, 4 speakers and a subwoofer. You can probably find them with the portable CD players at bestbuy/radioshack/walmart. I know i've seen it at one of those, i just can't remember which one. It'll be something like these: http://froogle.google.com/froogle?q=wireless+music+adapter&scoring=p

 

[Thoreau]

oh, this is just my experience, but those FM things kinda suck. Be sure to keep your receipt long enough to actually test it out and take a spin or two around the block before you finalize anything. In Phoenix, we have a CRAPLOAD of radio stations, so finding an open frequency with enough gap to avoid interference wasn't easy, then the range of those little transmitters is only measured in feet. I had the thing sitting in a dash pocket right below the radio headunit and still got shabby reception, but again, this is just my experience, YMMV.