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smadge1

Powering Laptop from Car's ciggie lighter

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I'm probably gonna spend a few days camping between christmas and new years, and I wanna keep using my laptop on the go.

 

What do people use

 

Inverters (12VDC to 240VAC)

 

or

 

universal laptop power supplies (ie, 12VDC to 19VDC)

 

Or should I get one of each for flexibility?

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I'd go the universal laptop supply as simpler and more efficient, although it's probably cheaper to get a budget inverter and continue using the existing laptop PSU if you don't care about long term (cheap and nasty inverters often don't last for years)

 

One thing to consider is some laptops are fussy - My work Dell laptop will complain if a non Dell PSU is plugged in (either my HP PSU or a 3rd party) - even with the same voltage and connector. It still works but nags me that it is non genuine and that things could end badly - So I have started locking the doors at night, and trained the cat to attack people's ankles just in case the Dell thugs come for me in the dark of a moonless night and try and stick my head on a pike.

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ok, I might have a look in jaycar first and see what they have

 

I have a 5m 12V extension cable, hopefully it'll reach to wherever my tent is.

Edited by smadge1

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I have a 5m 12V extension cable, hopefully it'll reach to wherever my tent is.

You're going to be stuck the next day when the car doesn't start.

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I'd still go with the inverter.. as a "mobile rep" for many years, the inverter proved invaluable - charging laptops,phonescameras and ipods etc all at once.. keep the inverter to a reputable brand and keep the wattage under 150W unless you're going to invest in heavy duty cabling or hardwire it..!!

 

(if you can hardwire the inverter - all the better, as a sustained 90-150 watts through a regular ciggie socket can sometimes generate a lot of heat)

ie: melt the end of the ciggie plug into a ball of plastic and metal !!

 

best efficiency acheived with a netbook or 65-70watt lappy charger.. and everything runs a lot cooler

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An inverter's advantage is that it's truly universal. There the advantages stop. I find some like to induce noise onto the 12V feed, which can create problems elsewhere. (One DSE PSU totally wiped out the 2m Amateur band for me on one trip whenever we plugged a radio and the inverter in together.)

 

They're much more complex, and it's a much less efficient way of achieving what you're after.

A universal laptop supply (for 12V) will be more efficient, however it needs to support the power consumption requirements and fitting of your particular laptop. This may not be so easy to achieve. I've had some fun and games doing this with my Lemote Yeeloong netbook... it uses what otherwise looks like a standard power jack, but I find many adapters lack this type of connector.

 

Either solution is not terribly expensive, so going both ways is an option. As for portable power... a small solar panel and a 9Ah 12V battery will allow truly portable operation. Jaycar sell some carry bags for the 9Ah batteries too... I've got two of them.

 

The 9Ah batteries aren't too bad, although they don't like being cycled or bounced around... and after about 6 months of being bounced around and heavily used on my bike, they're now starting to fail. I'm now looking at ordering two of these to replace them. In your application, SLA will probably be fine since you're not trying to pedal up hills with them, so even going a higher capacity pack is an option.

 

I think the main limitation here will be budget and desired battery life.

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I have just made this decision not that long ago and I am looking at giving it a test whirl soon. But I am also debating of scratching my battery and get something a bit larger.

 

External Battery/Case - I have gone for a 26AH Deep cycle battery (gel type). I would only recommend using either AGM/GEL types as the internal plate system is much thicker and you don't need to worry too much about killing the battery/Buildups. If your intention is to run a Laptop. Depending on its rated AH draw, try to keep clear of standard SLA or Car batteries. I have killed one too many in the past by over discharging on the field and risk stranding my car (no manual kick start here)

 

+

 

12vdc to universal dc converter up to 21.5V (I think) - I could of gone down the route of inverter, but then it becomes an issue of more wires and packs to carry around. My decision was purely on the basis of less wires.

 

Rob

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I've ended up buying a 300W Inverter and a 12V Universal Laptop Power Supply as well.

 

I'll probably use the inverter in short spurts, and leave the laptop connected via the universal PSU when I'm driving.

 

My car has a 12V jack in the boot too!

Edited by smadge1

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