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Laptop Power In The Car?


wizonkiz
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That three hour battery just doesn’t cut it for a full day of Geocaching. I need to get an adaptor to plug into my cigarette lighter, but what do I get? I think I have two options. A 12 volt to AC inverter to plug my Dell AC to DC adaptor into or a 12 volt to 20 volt adaptor that plugs directly into my Dell Inspiron/1100.

With the 12 volt to AC, I’ll be able to recharge all my electrical gadgets on the road, but will have a tangle of cords, it’s the cheapest option.

The 12 volt to 20 volt converter would be the cleanest solution, but it would only be useful for the laptop and is much more expensive.

I would appreciate your opinions and reasoning before I make my purchase.

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First you need to figure out the total draw with all of your gadgets plugged in - then get a 12V inverter with enough amps to handle everything. You can get inverters with multiple plugs.

 

Some of the newer SUV's have up to 4 12V plugs - but you have to watch how much you are drawing at one time, especially if your turn the engine off.

 

And always remember to only plug in the inverter once the engine is running, and unplug it before you turn it off. Even though they have surge protectors some devices still don't like the spike.

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First you need to figure out the total draw with all of your gadgets plugged in - then get a 12V inverter with enough amps to handle everything. You can get inverters with multiple plugs.

 

Some of the newer SUV's have up to 4 12V plugs - but you have to watch how much you are drawing at one time, especially if your turn the engine off.

 

And always remember to only plug in the inverter once the engine is running, and unplug it before you turn it off. Even though they have surge protectors some devices still don't like the spike.

Also make sure you know your alternator's output and how much "spare power" it has. If you are running a '73 Pacer with a 35 amp Delco alternator, hooking up a 1Kw inverter to it, and then expecting to be able to plug a whole bunch of stuff into it is going to give you "interesting" <_< results! Stay away from the small, cheap inverters that simply plug into a 12 VDC power outlet/cigarette lighter, and instead go for one which is hardwired into your vehicles electrical system.

 

[quote name=(bdaniel @ Feb 19 2004' date=' 11:49 AM)

The special Dell cord will cost big bucks. [/quote]

 

For about $7.00 in Radio Shack parts, you can make your own easily - it's a straight DC to DC voltage change.

Edited by tirediron
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I don't really know where, or to whom I should post this, so I'll put it here.

Recently when I post some kind of warn box comes up that seems to indicate

I have posted no messages.

I don't have many that have been posted, that's true, only 22.

My page also says that I am a premium member, which used to show when I posted

something, but no longer does. I have not changed anything, my email, and user name have remained the same.

 

Confused??

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I don't really know where, or to whom I should post this, so I'll put it here.

Recently when I post some kind of warn box comes up that seems to indicate

I have posted no messages.

I don't have many that have been posted, that's true, only 22.

My page also says that I am a premium member, which used to show when I posted

something, but no longer does. I have not changed anything, my email, and user name have remained the same.

 

Confused??

We all have warning meters, and you only see your own. As long as you are at 0%, you're OK!

 

You can change the title under your avatar by editing your main Geocaching profile.

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For about $7.00 in Radio Shack parts, you can make your own easily - it's a straight DC to DC voltage change.

Not so easy. The Laptop takes more the 12V, so it needs a voltage boost. Plus you do NOT want to connect a sensitive laptop to one of the most prolific creator of electrical spikes known to man, namely an automobile without some kind of protection.

 

That said, you may be able to find the proper DC to DC converter at Radio Shack with the right adapters to connect it to the laptop. I know they used to carry it, but I don't see it on the on-line catalog, but then I've had little luck with that stupid on-line thing.

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For about $7.00 in Radio Shack parts, you can make your own easily - it's a straight DC to DC voltage change.

Not so easy. The Laptop takes more the 12V, so it needs a voltage boost. Plus you do NOT want to connect a sensitive laptop to one of the most prolific creator of electrical spikes known to man, namely an automobile without some kind of protection.

 

That said, you may be able to find the proper DC to DC converter at Radio Shack with the right adapters to connect it to the laptop. I know they used to carry it, but I don't see it on the on-line catalog, but then I've had little luck with that stupid on-line thing.

:D Ok, I see it now, the laptop requiers 20VDC; still, it's not a difficult project, and a couple of big filter capacitors will take care of the spikes. I am not familiar with Dells, but a lot of laptops charge the battery and run the computer off the batter when on AC power, so spikes are not a major concern anyway. Besides who wants to buy something you can make anyway? Where's the fun in that? Isn't it sort of like logging your own hides? <_<

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You don't need anything fancy or expensive. You don't need a 1,000 watt device connected straight to the battery.

 

Your 120 volt AC transformer for your laptop probably pulls less than 100 watts. A cheap $29 invertor from Wal-Mart that puts out 150 watts will be fine.

 

Yes, it is cheap and will not put out clean sine wave 120 volts AC but the output goes back into a transformer that changes it back to DC so the input does not have to be very clean.

 

I'm a gadget nut and have done this for years with no problem.

 

Bobby

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Yup - I've been using an inexpensive inverter with my laptop and never had a problem.

So have I, and I plug mine in when I get in the van, and unplug it at the end of the day. I have the laptop, and every couple days, the AA charger plugged in. I probably start/shut off the van 8-10 times a day. The "accessory socket" I have it plugged in to has constant power, as opposed to switched power like many cigarrette lighters. Don't know if that makes a difference or not, but I haven't had any problems with starting/stopping the engine with the invertor plugged in and the laptop pluged into the invertor.

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Ditto the 12 - 120 converter.

 

I have a couple from Target, 400 watt items.

 

I run a laptop, a printer and even a laminator from them.

 

But, I hardwired them straight to the battery with a heavy gauge wire (outdoor extension cord with the ends cut off and heavy duty eyes soldered on both ends), both positive and negative sides, with a 40 amp inline fuse. And from the terminal end at the convertor, I also wired in a three socket power port setup.

 

Maybe not the ideal setup but it has worked for me for about 6 years now so I will stick with it.

 

logscaler.

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For about $7.00 in Radio Shack parts, you can make your own easily - it's a straight DC to DC voltage change.

Not so easy. The Laptop takes more the 12V, so it needs a voltage boost...

That said...

<_< Ok, I see it now, the laptop requiers 20VDC...

My Dell laptop has the 20volt AC to DC converter but the battery is rated at 14.8 volts output. Does this mean you can hook up 12volts directly? Don't know and will not find out.

I, also, have a 400watt inverter ($50 at Target)

With this setup, Northstar, and a dual auto DC outlet, I am able to power the laptop and my GPS receiver with the receiver connected to the laptop for autorouting.

It is a maze of wiring, but you can string the cables to minimize the clutter.

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I'm using a Wagan 150 watt inverter, that I bought at Frys Electronics (they have a website) paid under $30.00 for it if I remember right. It also has 2  115volt plug ins.

The worst lies are always at Fry's!

You can get good deals at Fry's as long as you're careful. Inspect the packaging carefully for their "restocked item" sticker, and avoid it if you find one. They put opened, returned items back on the shelf, and sell them for the same price as new. The only hint is the small sticker they're required to put on the box.

 

Keep your receipt and every bit of packaging. All the little bags and foam inserts. Everything. If you have to return something, they can deny a refund if anything is missing. But if you keep everything (until you're sure you want to keep it, or the return period expires), they have to accept it. The trick is to simply not give them any possible excuse to deny a refund or exchange.

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Thanks people, for all the advice, I tried to search for this question in the forums, but couldn’t find the answer. I didn’t want to ruin my $800.00 laptop, trying to save a few bucks. I had a few reservations about the 12 volt DC to AC converter, but now I believe that’s the route I’ll follow. Thanks again to all who responded, you people are great!

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Triac:

 

We got two of those 400 watt converters on closeout at Target right after Christmas for $7.50 each. New. One for each rig now. No replacing from one rig to the other. But I would advice to have them hardwired right to the battery with a 40 or 50 amp inline fuse.

I thought about that, but I don't think I'll ever run anything more than my laptop and maybe my rechargeable batteries on it, so shouldn't be a problem.

Thanks though, has me thinking again too.

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Okay, here is what works for me! I have a Jeep that has the extra outlet for power toys and of course it looks just like the lighter jack. Mine actually has heavier wire going the it but I still don't use it for the lap top. When you start the vehicle, it drops the power to everything except the starter. I have one of those jump start specials that you usually leave in the trunk of your car for times when you run the battery down and need a jump and nobody is around. It has two 12v jacks on the front as well as lights to tell me how much of a charge it has. I leave it in the back of the Jeep and plug in the 12v to 120v inverter. I then plug my lap top into this. I can run the computer all day on one charge and when I get home, I simply plug the jumper toy in and recharge it for the next use. You can work for hours and never have to worry about that spike. The lap top usually sits in the co-pilots seat with or without the co-pilot. Fur Ghost usually has the run of the back seat so I have to be a little careful of wires but that hasn't been a problem.

-=> The Ghost <=-

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Ok, I see it now, the laptop requiers 20VDC; still, it's not a difficult project, ..

I guess it depends on what you define as "difficult". It's not rocket science, but it's could easily be at the level of a cover page project in an electronics magazine. It certainly more then I'd expect or even try to do via a Geocaching forum. At low power you could just use a NE555 timer, a cap and a couple of diodes to build a voltage doubler, but a laptop take too much power for this approach.

 

and a couple of big filter capacitors will take care of the spikes.

Uh, not quite. Big caps usually have poor RF/high frequency response. That's why on better designs you'll see a small cap in parallel with a big one. The big one deals with the volt fluctuations and the small one does the RF/spikes.

 

But I'd still feel better with a inductor in series or at least a overvoltage protection like a zener diode. Cars have been known to really crank out some voltage if the regulator goes bad or the battery becomes disconnected.

 

I like building things too, but I find it better to correct deficiencies in commercial products then try and build from scratch. I almost always find it cheaper too. It's not the cost of the main parts the kill you, but the price of the nuts and bolts that finally drive the cost of the DIY approach higher then a commercial product.

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I use the iGo Juice system for power my toys on the road.

www.igo.com

 

The Juice70 adapter provides 70watts of power, enough for most laptops, AND you can hook up adapters to power PDAs & cell phones.

 

Also very cool is the fact that it is AC & DC, so it includes cords for running off standard 120V home power and has a cord for Car/Airplane.

 

Its pretty darn cool. I just leave this in my laptop bag, and keep the original power supply on my desk where the laptop usually is. I've always got power with me.

 

Hope this helps out - Oh, and you can get it pretty cheap from newegg.com too.

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I have been using my laptop only with the engine running. I see at least one person leaves their computer on while starting, and stopping the engine.

I have a '02 Ford Ranger PU, that has the cigarette lighter plus one accessory plug.

Both go to 0 voltage for a few seconds when the engine is started.

Guess I'll wire up something direct to the battery.

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I have a '02 Ford Ranger PU, that has the cigarette lighter plus one accessory plug.

Both go to 0 voltage for a few seconds when the engine is started.

Guess I'll wire up something direct to the battery.

Unless your systems are thrown off by the momentary loss of power, I wouldn't change that. Some of the worst voltage spikes will be during starting. Also keep in mind that the voltage may drop as low as 9V during starting, so you may no gain all that much by tapping the battery directly.

 

If you do set up a battery tap, be sure to fuse it.

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When I start the engine of my Explorer, the voltage output of the inverter is zero for about 2-3 seconds. I think this would be a disaster for my laptop. Windows does not do well when you lose power.

Doesn't your laptop have a battery? My laptop just swtiches to battery power if I turn off the AC power.

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The AC inverter is the only way to go. I use mine with a 4-way multi-socket: two for me (battery recharger for AAs for the GPSes and Laptop) and two for her (iron and hairdryer). It's the perfect solution as I can cache all weekend, and my wife is happy too. :ph34r:

 

Now all I need is a roof-mounted water tank and we can take the washing machine as well. However, I suspect the addition of the tumble drier might just blow a fuse... :ph34r:

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The Older lap-tops may not have a good battery. Mine is an old Gateway Solo that I picked up at a garage sale for 50 bucks because the owner didn’t want to spend $140.00 for a replacement battery. If I lose AC power from the inverter, the computer restarts. If you have a newer lap-top you may not have to worry about the voltage drop when you start your car. The battery will pick up the difference. I don’t take that chance. I use an external 12 volt supply hooked to the inverter hooked to the computer and I don’t worry about it.

-=> The Ghost <=-

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Doesn't your laptop have a battery? My laptop just swtiches to battery power if I turn off the AC power.

My question is, does the laptop switch to battery when the ac plug is in and it looses power, or does it switch to battery ONLY when the ac plug is removed making the switch from ac to battery. If the plug is still in, then loosing power to the ac plug won't help the computer and keep it from resetting.....

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The Older lap-tops may not have a good battery.

True. However some laptops require something that at least resembles a battery to "help out" during high power events like starting the hard drive. Or, a battery that starts shorting out may kill the power. Can't tell you how many laptops I've fixed by doing nothing more then replacing the battery even though the owner only uses it when plugged in. (But then that's probably what fried the battery in the first place - 24/7 charging.)

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