Inverter for use with laptop

**thonl** · 03-19-2004, 03:21 PM

Hi All:

New to the board, and I have been reading a lot, but would like a recommendation if someone would be so kind.

I currently use a laptop in my car quite a lot with a 125 watt power inverter in the cigarette lighter, and it works ok for that application. The only complaint is that if the outlet it is connected to is switched by the car, I have to physically switch the inverter off then on again to make it work after shutting the car off.

Recently, I bought a 2004 Saab 9-3 Linear, and I am in the mood to add a carputer, but am not sure about something.

The computer is a laptop that got trashed at work, that I managed to resurrect with an external monitor. It is a Toshiba Tecra 9000. 1 Ghz, 40 GB HDD, built in 802.11b, etc...

So the question is this. Would the 125Watt inverter I have now be sufficient to run this other laptop, as well as the Xenarc 700TS that I plan to add as a display? If not, is there something else someone might recommend? Also, if I set the laptop to hibernate after X minutes on Battery power, will touching the screen wake it back up again? I plan on mounting everything under the front passenger seat in a manner that will make loading DVD's for the kids to watch fairly simple, but I dont want to have to reach under the seat every time I want to wake the computer up.

-TIA

**Jackso** · 03-19-2004, 05:18 PM

Actually, the laptop uses DC power already. If you look at the box that is somewhere in the middle of the laptop cord, it will tell you that the laptop uses somthing like 12V DC @ 3A or something similar. As long as you are somewhere near 12V (probably 10V - 14V) you could make a cable with the approprate size plug to fit the laptop and connect it directly to the 12V in the car. You then wouldn't eneed the inverter at all.

**thonl** · 03-20-2004, 09:48 AM

Originally Posted by Jackso

Actually, the laptop uses DC power already. If you look at the box that is somewhere in the middle of the laptop cord, it will tell you that the laptop uses somthing like 12V DC @ 3A or something similar. As long as you are somewhere near 12V (probably 10V - 14V) you could make a cable with the approprate size plug to fit the laptop and connect it directly to the 12V in the car. You then wouldn't eneed the inverter at all.

Are the Xenarc Monitors 12v DC too, or what would you suggest, there?

Thanks!

**Jackso** · 03-20-2004, 03:57 PM

I'm not sure about the Xenarc monitors. They are DC, but I'm not sure of the voltage. But, since it is DC you could use a DC-DC converter like Radio Shack sells (similar to the cigarette plug used to power cd players etc.) and connect that to the Xenerac. Then everything in the car is running off DC.

**_maelstrom** · 03-20-2004, 04:17 PM

Originally Posted by Jackso

Actually, the laptop uses DC power already. If you look at the box that is somewhere in the middle of the laptop cord, it will tell you that the laptop uses somthing like 12V DC @ 3A or something similar. As long as you are somewhere near 12V (probably 10V - 14V) you could make a cable with the approprate size plug to fit the laptop and connect it directly to the 12V in the car. You then wouldn't eneed the inverter at all.

The laptop takes DC power, but you're going to need something more than just a wire running from the car battery. The laptop he's going to use needs 15VDC @ 6A. Something has to be in-line between the battery and the laptop to regulate the voltage. Something like this. You can cut off the cigarette lighter adapter and hardwire (with a fuse) the brick to your battery.

**CdRsKuLL** · 03-20-2004, 06:14 PM

hi fella, the way I would go about it is get one of these . This would plug into the 12v lighter, or you could cut off the end and direct wire it in, then the other end plug's into your laptop charger... otherwise you would need to step the power up which could be a hassle, as for your screen, this could be wired direct into the 12volt car supply, thats if it comes with a filter or a egg as the lilliputs do. As for the resume, touching the screen should work and wake it from its sleep. As for powering it on, I think you would need to press your power button. Theres prob some clever guy thats sussed how to get round that one..

hope some of this info helps

steve

**Marsupial** · 03-21-2004, 12:21 AM

For my lappy I use a DC converter similar to this
http://cgi.ebay.com/ws/eBayISAPI.dll...category=20376

if it can help...

**Jackso** · 03-22-2004, 05:39 PM

Originally Posted by _maelstrom

The laptop takes DC power, but you're going to need something more than just a wire running from the car battery. The laptop he's going to use needs 15VDC @ 6A. Something has to be in-line between the battery and the laptop to regulate the voltage. Something like this. You can cut off the cigarette lighter adapter and hardwire (with a fuse) the brick to your battery.

It may be true that his power supply provides 15VDC @ 6A but that does not mean that the computer will require 15VDC. Consider that all computers use 12V, 5V and 3.3V. Now consider the battery on the laptop, chances are that it too is most likely 12V. The computer will very likely run on 12V and just think that the battery is running low. I have done this with a couple of different older laptops, not necessarily his brand, but for the cost of trying, you're not going to hurt anything if it doesn't work.

**divideoverflow** · 03-22-2004, 05:46 PM

Originally Posted by Jackso

It may be true that his power supply provides 15VDC @ 6A but that does not mean that the computer will require 15VDC. Consider that all computers use 12V, 5V and 3.3V. Now consider the battery on the laptop, chances are that it too is most likely 12V. The computer will very likely run on 12V and just think that the battery is running low. I have done this with a couple of different older laptops, not necessarily his brand, but for the cost of trying, you're not going to hurt anything if it doesn't work.

Yup! I concur. My Compaq laptop AC adapter label claimed 19v I think and I ran a cigarette adapter right into the laptop with no problems. That worked for me. Your mileage may vary, but like he said you're not going to hurt anything if it doesn't work.

-- divideoverflow