12V dc -> 16V dc converter

whipper_snapper

whipper_snapper

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Hi again

I am looking for advice on a device for powering a (Vaio) laptop from a nominally 12Vdc 'cigarette lighter'. The computers power brick states an output of 16V 4A.

Given that the input will go up to 14.6V when batteries are charging and drop to 12.2 when they are low, it is presumably quite demanding on the electronics. I have had bad experiences with cheap devices in the past which have not lasted and have run very hot although theoretically used within specs. I have also had bad experiences with inverters as they make a lot of RF which causes problems with Wx fax receiving.

So any suggestions for a specific device which has proved reliable ?

Thanks
 
considering the high price of a Sony laptop and your problems in receiving weather fax with an inverter (did you try a true sinus inverter ?), I would buy the original Sony car adapter.

Why are you not using the inverter to charge the battery and receive your weatherfax using the freshly charged battery ? Thats the way I have done it, as my car 12 Volt - 16 Volt converter was also giving bad reception.

Peter
 
Maplins do a gadget specifically for powering laptops from a 12 volt supply, going up to 24 volts for £29.99. The only problem I found is that they are alomost as Amp hungry as running the laptop through a 12v-mains invertor. Cat No L40BB. There is a lower power version at £20 too, if your laptop doesnt need so much power.
 
I use the higher spec Maplins device from the 12v socket while sailing (don;t like having mains voltages about when potentially wet) and also sometimes use the invertor when in dock. Either way around the laptop requires the same power and the only variable is the efficiency of the adaptor vs invertor (power going in - amps x volts - against power coming out). I'm guessing, but I wouldn;t think there was much difference between them.
Something I have considered is using a bank of three 6V motorbike (?) lead acid batteries (18v) specifically for the laptop which would be 'trickle' charged by the maplin device so buffering the amps drawn from the main battery bank esp when sailing. But I'm not sure the effort is worth the return.
 
The lower power Maplin device gives 3.5 amps at 16 volts (you can select voltage output). My guess is that if the Sony power supply gives 4 amps it is set up to give the maximum power the laptop needs with everything running including the CD or DVD and charging the battery. A 3.5 amp supply would probably be perfectly OK. (I am now prepared to be shot down by the experts)
 
In Manchester airport the other day I noticed that Dixons are selling laptop power supplies for use with 12 volts for around £60. They are very small (about the size of a pack of cards) but cant really say if they are any good.
see below

power supply
 
Don't be seduced into trying to save money here - your computer needs 16v and 4A which will require 5.3A at 12v even with a perfect conversion. Since you never get perfect conversion you're probably looking at drawing more like 8A, so a 4A convertor is not going to work. All that will happen is (in ascending order of catastrophe) the voltage will reduce until your machine stops; it gets hot; it catches fire and burns your ship to bits. Buy something that can deliver more power than you need and don;t take risks - your computer won;t take the Amps it doesn;t need.
 
Thanks all. Some useful suggestions here. And I agree that the desire to avoid 240VAC in a wet environment is another good reason for not going with an inverter.

I certainly do not want to risk a failure in order to save a few pounds. The Kensington PSUs that Mr Squarepants suggested certainly look smart, and appear to have plenty of capacity for my needs. But I am still unsure of how to tell what is worth a bit extra and what is not. I guess I will just go for power overkill!
 
Maplins Energy Knight at 29.99 has served me well for near 2 years now .... and caters for 12 up to 22V ..... used it on IBM TP's, Maxdata, Acer, Siemens Scenics, Ensys and Twinhead as examples. Only problem has been with Dell and others that use strange power connectors.
 
Never heard of a laptop catching fire when using a power adpator like the Maplins - my old IBM works perfectly, as does SWMBOs Dell, both rated very close to the maximum output of the gadget, and we have used these Maplin things regularly, both aboard and on the road for a couple of years now.

The only problem arises I suspect if you are stupid enough to try to use a Laptop with a 5a supply demand on a 3.5a convertor, in which case the convertors thermal safety fuse cuts out long before there is any danger if fire.

I have also heard it said both here in the forums and elsewhere, that most 16V Laptops run quite happily at the notiona 12 - 13v of a ships supply, with just a little loss of brightness in the dispaly. Never tried it though!
 
[ QUOTE ]
Never heard of a laptop catching fire when using a power adpator like the Maplins - my old IBM works perfectly, as does SWMBOs Dell, both rated very close to the maximum output of the gadget, and we have used these Maplin things regularly, both aboard and on the road for a couple of years now.

The only problem arises I suspect if you are stupid enough to try to use a Laptop with a 5a supply demand on a 3.5a convertor, in which case the convertors thermal safety fuse cuts out long before there is any danger if fire.

I have also heard it said both here in the forums and elsewhere, that most 16V Laptops run quite happily at the notiona 12 - 13v of a ships supply, with just a little loss of brightness in the dispaly. Never tried it though!

[/ QUOTE ]

Get a cheapo Notebook like an IBM Thinkpad 600E ... take out battery ... wire in 12v direct ... works fine. In fact I have done this with various NB's I have ....... and all worked. But take out or isolate battery otherwise it probably won't boot-up.
 
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