plugging laptop into 12v transformer

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ColinR

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www.victoriashadow.co.uk
I bought one of these in Maplins to convert 12v dc to 19v dc which is what my laptop needs. It plugs in to a cigarette lighter type socket. My new laptop has dire warnings about not plugging in to anything except via the power lead and transformer that came with it. Is there likely to me a problem with this? Surely 19v dc is 19v dc wherever it comes from. Or will the boat supply fluctuate too much for instance when I am running the engine?The other solution is to use my inverter but is seems daft to convert 12 dc to 240v ac then back to 12v dc and presumably is more of a drain on the battery?

Thanks

Colin
 
I have had 2 laptops on my boat over a year, one was 12v the other 19v, the 12v worked ok but I could not get a cig socket for the 19v one so I made one out of an old adapter that fitted, cut the wires use a meter to find live, wire it up to a 12v plug and it worked fine, even though I was giving 12v to a 19v supply it was enough to charge the battery.
 
The supply will maintain 19v output over a fairly wide input range (12-15v?)
I have used one for years and it makes no difference if engine is running or not.
Only thing is, if you blow laptop up and happen to mention to the manufacturer how you were using it when it blew, you will find out why they post all those dire warnings...it's called a void warranty!!!
 
if you were manufacturer and you knew people out there were plugging all sorts into your gear - what would you say ?

But back to your question - I have used all sorts of notebook PC's on my Maplins DC - DC converter ... most I don't even bother to change the voltage setting - mine uses blade inserts to alter voltage ...

As others say - you can plug into 12V direct as well. Better if battery is out though.

I use power supplies from various dead notebook PC's to power others ... so that we don't have to carry power supplies house to office etc. Just because it says ACER - doesn't mean it can't work on a Compaq etc. We even use 16V IBM power supplies on 19V notebooks ... charging is just weak thats all.

As to varying voltage ... never had a problem. In fact my maplins job cuts out when voltage drops to low ..
 
As a matter of interest I just tried two laptops plugged directly into a 12V D.C. cigar lighter socket via a cheap Altai adapter (one where you can select different output tips to suit your device)

1st laptop: IBM/Lenovo T41p which has a standard 3 cell LiPo battery (10.8V nominal) this one worked fine with or without the battery and charged the battery when it was installed.
This one has a 16V/mains charger

2nd laptop: Compaq M300 which has a standard 4 cell LiPo battery (14.4V nominal) this one worked fine without the battery installed but, as mentioned above, it's probably a waste of time to install the battery with this one as it won't get charged at 12-14V.
This one has an 18.5V/mains charger

In other words any laptop which has a 3 cell LiPo as standard is probably safe to use and charge from a 12V D.C. supply although I would personally prefer to have some kind of regulated adapter rather than just a straight fused cigar lighter plug.

Some 4 cell (14.4V) standard notebooks may also work O.K. judging purely by the one I tried.

HTH
 
I would agree with you ... in what I've seen as well ... my IBM Thinkpad at 16V has no problem via direct 12V or the Dc-Dc converter.
But 18+V stuff I have not had much success with batterys charging ... and is why I advocate removing battery. Charge up fully at home ... take out on boat and run NB on 12v / Dc-Dc converter ... Battery stays in bag as emergency back-up if needed.

Some say - if battery is fully charged before - then leave it in ... I disagree - when you read CD / other stuff ie - Cards / flash drives etc. - the battery is called on to boost power initially when it starts to read etc. - this slowly drains the battery.
 
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