can I make a ciggette lighter plug for my laptop

[lotust]

I have a Toshiba 650ct it says on the AC power adapter 120VAC input and 14 volts 2amps output. So is I make a cigarette lighter adapter will it work? Or is there too much amperage in the cars battery?

 

[Zenmervolt]

Most companies make auto adaptors for their laptops. Call Toshiba and order the one made by them. If you try to make your own and do something wrong it could be a $3000 mistake, as a jerry-rigged auto adapter would certainly void your warranty. Alternately you could buy a power inverter for your car (a power inverter a box with a normal plug-type outlet and a cigarette lighter plug that converts the car's DC power to AC at household voltage). You could plug the power inverter into the cigarette lighter and your standard AC adaptor into the power inverter. Trying to jerry rig an auto adaptor is, in my mind, taking a very expensive gamble.

Aaron Meyer

Edit: Just looked at Toshiba's site, the auto adaptor for the Protege 650CT is part number NW801L and it retails on the Toshiba website for $99.00. The address for the web page is herehere.

 

[lotust]

But I like to make my own stuff . I have a inverter allready. But I belive it must be a SIN WAVE output wich is much cleaner than a normal inverter. I dont think a computer would like any kind of AC inverter noise. A real good inverter would cost 200$ mine was 80$ from AID Auto store.


More input please



thanks Zenmervolt for you input

 

[MWink]

<< But I belive it must be a SIN WAVE >>



That would probably be better but it is by no means necessary. Most UPSs put out stepped wave and few computers have a problem with that.

 

[lotust]

thanks MWink thats the kind of info I like. How did you know of this?

 

[RossGr]

Your Laptop power supply's output is probably 14V DC. Not AC, Runs on batteries right? Must be DC. The trouble is 14VDC. Your car battery is only 12V. NO, YOU DO NOT HAVE TO MUCH CURRENT! The device connected to the battery will draw as much current as it needs. The starter draws lots of current, your Laptop draws 2A at 14V it will draw less at 12V. You may be able to make a cig lighter to what ever jack your Laptop needs cable and be good to go. Perhaps you will not charge your Laptop batteries. I would definitly check with the manufacture on this.

 

[randypj]

My Dad had an older P100 Toshiba-based laptop which ran fine from a normal cig lighter plug. His and my newer require an inverter (Celerons).
--Randy

 

[lotust]

A huh , when a normal car is running the voltage is actually at 14.50-15.00 volts Dc. Not 12 Volts. 12 volts is when the car is not running.
But thanks everyone for all this really good input on this matter. I am starting to think this will work ok. After all why should I spend $$$ when I can make it myself.

 

[bigjon]

The problem isn't so much with the voltage as it is with the voltage variation. It's not uncommon for a battery to drop to 9 or 10 volts during cranking, and while running it is usually around 14.5 to 15 volts, as lotust mentioned. Voltage variation will strain any electronic device, and a laptop is something I'd be a tad careful with If you could rig a voltage regulator it would be much safer than a straight-through cig plug. A voltage invertor (12vdc-115vac) should work fine (I do it all the time). If you have an AC adapter it has some filtering built-in so the modified square wave/sine wave issue shouldn't be a problem.

 

[JackMDS]

You can buy a DC to AC converter, and keep it in the car.

DC to AC converter is a small box that plugs to the lighter and has a 110V AC out put.

You just plug the regular Laptop charger into it, and works like you are at home.

DC to AC converter comes according to Wattage (Power), the more Power the more money it cost, but you need only 28W (14Volts X 2Amp. = 28 Watts).

Radio Shack sells them, basic unit $70. You can find much cheaper one, by doing a search at the Electronic surplus sites.

At Radio Shack

 

[JackMDS]

Found also this: At Radio Shack

DC to DC adapter.

 

[ArkAoss]

Hey lotust, whats up with virtualhideout.net? but yeah, go for it if you think you can make a bat charger for a laptop, go man, I'm gonna adapt a psu to run from a cig adapter my self, but regulating the volage will be a major pain. It'd require some in deapth electronics knowledge to build from scratch. If ya need any help, i can pull up some of my notes from school, and send em to ya.

 

[beat mania]

Lotust: how much do you know about electronics? I'm wondering since you ask of whether the battery would supply too much current ...

First of all, I believe that the car battery's voltage can vary between something like 9V - 15V. I wonder if there are special voltage regulators that can both step up and step down? There are probably specialize voltage regulators that can do that. It has to go from as low as 9V -> 14V and as high as 15V -> 14V. But that is cheating A less efficient, but safer and easier way, is to make a voltage regulator that can do (9-15)V -> a certain voltage. Then make another voltage regulator to convert to 14V. A lazy way is to just assume that it won't go over 14V very much of the time and ignore that. The laptop can take an extra V or 2 anyway. It has its own voltage regulators inside. In fact, I think if you supply less than 14V it would still work, probably the determining factor is the inverter for the TFT. I can't think of anything else inside that would warrant the need for 14V voltage anyway. ... maybe the audio...

Since the voltages are very close to 14V to begin with I don't think you'll need to worry about mad heat dissapation from the voltage regulators. But don't forget a fuse!

 

[lotust]

hello every one
Zenmervolt: thanks for the link. But 100$ is too much I think.

bigjon: you right on the Voltage drop. I think My Inverter is gonna do the trick.

JackMDS: dont take this the wrong way But if you read my post I said I have an Inverter <I have a inverter allready. But I belive it must be a SIN WAVE>

ArkAoss: what do you mean whats up with virtualhideout? ( I work there ) We had some server troubles if thats what you mean? I think its all fixed now (we hope) Thanks for offering your notes though What are you going to school for?

beat mania: <how much do you know about electronics? I'm wondering since you ask of whether the battery would supply too much current ..> I have about average knowledge of eletronics( I think any way :cool I wanted to know if the batter had to much current beacuase I did not know if the laptop had a regulator inside. I did not want to just supply the lappy with 500amp's he he he When it really only need the 2 amp's.


Sorry If I let anything out. I am dead tired today (long day) Fell free to E mail me anytime though.

 

[ArkAoss]

From work I couldnt get to VH. I can now.
I was in school for deep electronics, component level, we spent alot of time building powersupply's and makling voltage regulators, and I think I have my notes someplace, I worked on a few special projects and have notes on them, Lotust, do you have a oscilliscope? you could hook up the laptop psu to the wall and measure the out put with that, then just design a circuit to work from what a car battery could supply, and the possible variations, and have it out put what the laptop out puts. Doable enough, and laptops make it easier, to reverse engineer what i'd need to make a standard case psu work from a car will be a major pain when i get around to it. if you dont have access to a scope, I do, and i might be able to get access to the same toshiba laptop power adaptor, and i might be able to take some readings for ya or help ya out in some way, but without some mid level electronics bench aparatus I wouldn't suggest trying out any creations



One of these days I'm gonna make a disertation on PSU's and make MY way into anandtech fame

 

[ArkAoss]

YO any body still reading this thread? lotust? you live? i'd like to see if we can build this

 

[Mark R]

To me, this sounds like a fairly tricky project.

The problem is that the variability of input voltage means that the required input range spans the output voltage - there's only one really good circuit that will meet these criteria, and that is a flyback voltage converter.

The problem with this, as with all switched-mode regulators is that they are tricky to design and build - you need to make sure your transistors meet the necessary requirements and the inductors must be just right. You might be able to find a suitable monolithic SMPS controller [1]which has the transistors built in - just add a suitable inductor, which you'll probably end up having to wind yourself.

Don't forget that you'll also need some form of failsafe protection circuit - a crowbar is usually used in this situation.

[1] Try taking a look at the National Semiconductor catalogue.

 

[ArkAoss]

bumping it to the top,

and if i didnt have a full time job i'd probly be able to build a psu from scratch, but then i wouldnt have money, or the amount of postage i have

 

[lotust]

<YO any body still reading this thread? lotust? you live? i'd like to see if we can build this>



hey Arkoss I dunno about this. I think I will take the cheap way out and use my 12volt to 110volt ac inverter to save my @ss. I have no time tight now to build one. but thanks alot man.


EDIT: like eddie veder says AAAAAAAAAAaaaaaaaaaaa Im still alive Aaaaaaaaaaaaaaaaa Haaaaaaaaaaaaaa Ya