Do I need a pure sine wave inverter to run a laptop?

V1701

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Evening all, thinking of using laptop & GPS mouse for navigating, if I do would a cheap inverter from ebay do the job or do I need a pure sine wave one?
Thanks,
David.
 

dancrane

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Young fellow in Maplins told me laptops are much more robust than pure-sine inverter manufacturers would have us believe. He was very convincing; it sounded like you'd have to be terribly unfortunate to be let down by a quasi-sine version.
 

sarabande

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djb - it's marginal but significant, with inverters being 80% efficient, the 240 transformer being similar, and a lappy drawing, say, 70 watts.

The less changes of frequency and phase you have, the better. Additionally, there's less RFI to act, possibly, on the radios.
 

Coaster

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As suggested by Sarabande, we charge and run a Lenovo Thinkpad T400 laptop and a Samsung netbook using 12V car-type chargers. No problems so far. I believe it's much more efficient than stepping up from 12V DC to 230/240V AC, then back down to whatever DC voltage your laptop requires.
 

boguing

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This is 10 year old experience - treat it with a pinch of salt.

Non-Sine inverter was happy with a laptop, but destroyed a mobile 'phone charger and a leccy toothbrush charger. I had a spare 'phone charger which was fine - but I used the laptop as a buffer to protect it.

We were right worn out after three weeks of manual brushing.
 

idpnd

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Yes +1 on the 12V lighter plug converter, they are cheaper than inverters & usually come wiht lots of little plugs + variable voltage so you can use them to drive lots of DC transformer driven gimmicks. Works in your car as well ;)
 

Conachair

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Evening all, thinking of using laptop & GPS mouse for navigating, if I do would a cheap inverter from ebay do the job or do I need a pure sine wave one?
Thanks,
David.

My toshiba works fine on a cheapo invertor but very hungry, can pull over 7A if it's being used and charging the battery at same time.
As others have said the maplins car chargers are much more efficient, I have 150w one which pulls just over 4A if charging the batt & being used.
 

Searush

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Another vote for a cheapo e-bay a 12v car supply for the Lappy. But be aware it can still use a fair bit of power, either on the net all evening, or as a plotter on a longish (like all day) sailing passage. I doubt my domestic battery could cope with both without a decent recharge (say running the engine for an hour or so).
 

semisimple

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Does anyone know of one that has a connection that will fit a MacBook?

Not that I know of, you'll have to buy a specific macbook/pro dc car/boat charger, I know Hypermac used to do one but it was quite expensive in the UK - imported from the states $50 or so.

If you do an internet search you'll find it, (and I'm sure there are others)
 

silver-fox

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I have fitted a couple of car type cigar lighter sockets by my chart table. They are very cheap to buy and easy to fit and provide an easy way of tapping into products made for the car market

I use this to charge many different devices, typically lap top, Ipod, phone charges, etc etc.

I have an inverter for bigger requirements, power tools etc but I am of the opinion that an inverter is inefficient compared with the DC/DC devices
 

skyflyer

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let me get this right..

take 12v, use an inverter to make it into 240v and then plug in a laptop charger that transforms it back to ~12v

What am I missing?
 

semisimple

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^ the fact that the type of an inverter is an issue (DC to sine, triangular or any number of different wave forms) - and the horrible inefficiencies in going from DC to AC to DC again, I guess.
 

noelex

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let me get this right..

take 12v, use an inverter to make it into 240v and then plug in a laptop charger that transforms it back to ~12v

What am I missing?
Most laptops need 17-20V (there are a few small laptops and netbooks that run directly off 12v, but not many). A 12v laptop charger has a nominal input voltage of 12V, but the output voltage will be higher.
 

CelebrityScandel

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^ the fact that the type of an inverter is an issue (DC to sine, triangular or any number of different wave forms) - and the horrible inefficiencies in going from DC to AC to DC again, I guess.

You should get out of the habit of guessing when you give advice.

The 12v step up supplies also work by going from DC to AC and back to DC again; they need to do the AC step in order to produce an output DC voltage that is higher than the input one. So by your account they must also suffer from the same "horrible inefficiencies". But you are not alone as I see another poster has also made a similar uninformed claim.

Any efficiency difference between using an inverter and the notebook's power supply and using a 12v step up supply is likely to be mostly just one of scale.
 
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