DIY Laptop (Dell) Car Charger
Mar 8, 2006 at 11:43 PM Thread Starter Post #1 of 8

xluben

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Would it be possible to (easily) do this without risking damage to my computer?

I have the lighter adapter that I can take apart. I'd need to find the correct plug (Radioshack?, center positive/negative?).

The wall charger it comes with says 19.5V, 3.34A. Would it be OK to just feed it 12V from the car plug?

If this is much harder than finding the right plug and soldering some wires I'll probably just give up on it, but if it's realatively simple I'l give it a try, because I have a 10 hour car ride coming up on spring break.
 
Mar 9, 2006 at 12:56 AM Post #3 of 8

mono

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It is much harder than finding the right plug and soldering some wires.

The lighter outlet is roughly 12-13.8V, which will need a voltage boost to the 19.5V level. A transformer is going to be hard to source, expensive and relatively lossy so the typical solution is a switching supply. Essentially you'd be building exactly what you buy for $25, from scratch at similar or higher expense and a great amount of time. Just buy the pre-made car adapter, it is defintely worthwhile.
 
Mar 9, 2006 at 3:07 AM Post #4 of 8

xluben

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Mar 9, 2006 at 3:19 AM Post #5 of 8

mono

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The best solution is not a cheap inverter, it's an official laptop car adapter. Very cheap inverters can have poor output, and then you're left carrying around twice the parts. If you "need", want, (whatever) a car inverter for multiple uses, ok, but better to get a larger more versatile unit for that. 300-500W inverter can be had for under $50.

The laptop adapter all-in-one supply plugs into the car lighter, has a cord with the 19.5V DC output. There is no inverter involved, it is the entire supply.

You might find the best prices for something like that on ebay, just make sure it's rated for about the same amperage output as your current supply (if not a little more) and has the correct plug to fit your laptop.

This is only an example.
 
Mar 9, 2006 at 3:27 AM Post #6 of 8

cire

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a cigarette lighter inverter will work fine. the most you should ever draw from it is 150 watts continuous, so anything more is overkill. i think you should still follow the 70% efficiency rule, though.
 
Mar 9, 2006 at 4:16 AM Post #8 of 8

cire

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70% efficiency by switching powersupplies at peak. so if something's rated for 100 watts, then you'd expect that the most you could draw continuously without things blowing up or lighting on fire is 70 watts.
 

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