hey guys. so when i was up in chicago last, i picked up my old compaq laptop running vista from 2008. its got some issue with the network card where it wont work unless its connecting to an open network even if you type the correct password in.


so, since it will only work with a wired internet connection, which would defeat the purpose of a laptop i figured id put some games on it, and leave it in the pocket of my seat for roadtrips. my only problem, is i really dont want an inverter in my car, and i want something permanent so i can hide the power cord.

so, my question to you guys is, the laptop runs on 9v dc. if i cut the power cord, before the power cords inverter, will the inverter convert the 12v dc into 9v dc? as opposed to 120v ac to 9v dc.

thanks alot!!

No, the laptop "converter" converts 120 AC to 9 DC. If you were to try and feed it 13.8 VDC, ummm, more than likely you would pop a fuse.

Now, what you could do is, measure the voltage from the laptop power cable. Though the label does say 9VDC, more than likely, the actual voltage is higher. Probably around 11-12 VDC. If its closer to 12, you might be able to direct feed it to the battery.

What does the powersupply say, 9VDC at what AMPs?

you cant trust open circuit voltage to be right after its pluged in it might go back down to 9v. you could build a dc-dc converter but 9v is low so your current is going to be high, might be cheaper just use an inverter and the cord you have. or you could look inside there must be another supply in there because the pc is going to use 5 or 3.3v not 9, there may be something handier you can do with that. ill have to look deal with computers too much at work dont want one in my car.

Most "converters", (things that change household voltage of 110AC to DC) overshoot the labeled rating when devices require battery recharging.

If the powersupply says 9VDC at 5amps, and if he found a different powersupply that said 9VDC at 500amps, they both would work just fine. BUT. If the power supply said 9VDC at 900milliamps, then he would be screwed.

I can pretty much say with certainity, that any "wall wart" you find in your house, is showing more voltage than what the label says. Or any step down converter for that matter.

if you measure the voltage of the thing sitting there unplugged, and it shows 10 or 11v that really dont mean anything. because the voltage will be closer to listed output when plugged in and providing current

nevermind. sorry guys. i was looking at the wrong laptop charger.i tested them both with the meter. the compaq puts out 19 volts, my new computer puts out 9.

By the way, you can either get a USB wireless adapter, or if you have an empty card slot, you can a wireless card and get your wireless internet back on the laptop.

If you decide to use your other laptop that is running on 9 volts, you can build a voltage regulator that will plug into a cig lighter or power port provided that you don't draw more current than those circuit provides.