Need help converting

[daimleramg]

I need some help with some conversion, my laptop power cord says 125V 7A so how many watts is this? I looking to buy a digital power inverter for my car so I can charge my laptop there but will a 400W power inverter suffice? Or do I need a bigger and more powerful one?

 

[cottonpickers]

Thats about 1000w (175x7) but its unlikely that your laptop will actually draw that amount. More likely around 100w

If you just need to charge the laptop, I would get a car/plane charger (kensington or igo) that will charge your laptop and other gadgets. It will use less power (less converting going on) and will be smaller. If you don't want to go that route, personally I would get a small inverter - maybe even 150w. Its likely that that will be fine. Remember that most car cigarette lighters are 10 or 20amp (10x12volt = 120w) so you don't want to use too large an inverter or you will blow the cigarette lighter fuse

 

[jellydonut]

P = U x I

So in this case 125V x 7A = 875W

I somehow doubt a laptop charging brick actually uses 875 watts though. That's quite a monster even for the hairiest desktop computers, and those PSUs have active cooling.

doh, beaten.

 

[daimleramg]

Here's my power bar, its huge the tag on the right that is connected to the wire says 7A 125V.

I have an Asus G51J gaming laptop with intel CORE i7-720QM, nVidia GeForce GTX 260M 1GB, 2x 320GB HDD, 4GB ram. It's a pretty power hungry laptop, without being plugged in I can only use it for 45 mins on a 6 cell battery.

 

[alpg88]

i,m not sure what 125v7a mean on the wire, but i,m pretty sure your power supply is about 150w, no reason for laptop to have 1000w power supply.
to be sure 200w inverter will be more than enough, mine none gaming laptop charger works fine off 150w inverter.

 

[Lynx_Arc]

sounds like it would charge fine off a 150watt inverter but I doubt it would run off one with all that hardware you have in it there will be a big difference in charging power vs operating power as your charger is probably designed to keep the battery from discharging while the laptop is on otherwise even with the charger plugged in the laptop would still be discharging the battery when running. If you want to operate your laptop in your car you will probably have to get a larger inverter with heavy cables connected directly to the battery. My desktop computer has a less powerful processor using less ram and one hard drive and draws 150watts sitting idle, more when you start gaming. I would guess your system uses at least 50% more power when pushed hard and the limit you can pull through many cigarette lighter (12v power plugs) is 15A or about 180watts. My 150watts doesn't include monitor as my monitor is a 19 inch CRT. And converting from 12vdc to 120vac isn't a 100% efficient process you lose power in the conversion.

 

[jellydonut]

Input: 100-240V 2A
Output: 19V 6.32A

That's 200-480 for the first one and 120W for the second one.

The wire is probably just overspecced.

 

[alpg88]

sounds like it would charge fine off a 150watt inverter but I doubt it would run off one with all that hardware you have in it there will be a big difference in charging power vs operating power as your charger is probably designed to keep the battery from discharging while the laptop is on otherwise even with the charger plugged in the laptop would still be discharging the battery when running. If you want to operate your laptop in your car you will probably have to get a larger inverter with heavy cables connected directly to the battery. My desktop computer has a less powerful processor using less ram and one hard drive and draws 150watts sitting idle, more when you start gaming. I would guess your system uses at least 50% more power when pushed hard and the limit you can pull through many cigarette lighter (12v power plugs) is 15A or about 180watts. My 150watts doesn't include monitor as my monitor is a 19 inch CRT. And converting from 12vdc to 120vac isn't a 100% efficient process you lose power in the conversion.

it will run fine on 200w, when i said charging i meant charging and working at the same time. i,ve done it thousands of times.

 

[LukeA]

Here's my power bar, its huge the tag on the right that is connected to the wire says 7A 125V.

That's the current rating for the wire and the voltage rating of the insulation. It's probably 22ga.