Power afloat for a laptop PC

[alldownwind]

Sorry if this has come up recently, although I can't recall this specific query being asked.....
I'd been looking around for a laptop to use at home, and tinker with afloat - although I'm probably not serious about using it to run a chartplotter (I already have a Yeoman).
On a whim I bought one in Tesco today, last day of a sale when all their laptops (if you could find one!) have 20% off. The machine itself is probably quite a bargain, but I'm a bit worried to find that the AC adaptor pumps out 19v. Presumably this means the machine won't run on 12v!
Query is, do any laptops run on 12v, and if not, how does one get round this, please?

 

[jerryat]

It probably will run on 12v, but the battery will not be charged.

Run a search on here for loads and loads of similar discussions!

 

[Phoenix of Hamble]

Go to ebay and find a laptop car power kit DC-DC converter..... will step the voltage up to 19V for you.... thats what I do, and it works very well.... I simply bought a cigarette lighter socket, and fitted it permanently.... useful, as various other bits seem to also have 12V options with cigarette lighter connectors

 

[Swagman]

Maplins do one with adaptors for various laptops. www.maplin.com.

 

[Kendal]

try this

Maplin Laptop Power Adaptors

 

[FWB]

If you ring these guys they will supply you with a dc/dc converter with correct plug for your particular laptop.

 

[fireball]

The 19v ones will not run on 12v .... yes - I tried it .... so the DC-DC converter is probably the best way forward ... otherwise an invertor is ok - but sometimes the stepped ones (the cheaper ones) won't run the laptop powerpack correctly - found this with the crapard hell unit ... so had to find a fujitsu one to swap out with ... but the acer one I've got now seems to work ok ... /forums/images/graemlins/laugh.gif

Now, if you can find yourself a 15v laptop, they will run on 12v - just doesn't charge the battery, but at that age the battery is probably knackered neway!

 

[Guest]

12 - 19V

I have inverter .... works ...

I have Maplins Energy Knight DC - DC converter..... works fine.

I have 12v direct in .... works fine.

The notebooks differ from 16v (IBM Thinkpad 600e) up to 19v (Acer Aspire)

ALL I have taken battery out and connected to 12v ... worked. OK the LED's say no ... but it does. The problem generally is that the battery will draw the power unless full charged. I did on one when battery was part discharged ... start NB with battery in ... once started - pull batt pack out !! But I do not recc'd that ... the NB doesn't like it ...

Another point - reduce all peripherals / add-ons to the NB when in use ... that way power draw is significantly lower. Charts - read from hard drive if possible, reduce CD's top absolute minimum. Have a hand-held GPS powered from 12v and not a GPS mouse powered from USB etc. etc.

One of the biggest head-aches is where some companys like Dell have completely different connectors for power in and I believe that its Dell that have some NB's that have a 3rd wire which stops a DC - DC converter working properly on them ... but not having a Dell - I only go by what I hear ...

 

[Helina]

Re: 12 - 19V

I have HP laptop and when I asked in the shop for a cigaret lighter transformer, they said it would ruin the laptop in long term ??and recommended a small inverter 300 watts which I bought , costed some 50,- euros and it works ! With the same unit I can charge the camera battery , electric shaver, tooth brush, mobile and satellite phone ..... etc

 

[finnlou]

Re: 12 - 19V

[ QUOTE ]
I have HP laptop and when I asked in the shop for a cigaret lighter transformer, they said it would ruin the laptop in long term ??and recommended a small inverter 300 watts which I bought , costed some 50,- euros and it works ! With the same unit I can charge the camera battery , electric shaver, tooth brush, mobile and satellite phone ..... etc

[/ QUOTE ]SOunds like the salesman was telling you porkies, you can not damage the laptop by using a DC-DC convertor to power it, what do you think the power supply does that you plugged in to the inverter

 

[Guest]

HP and Inverter ....

Of course it works ....

50 Euros for Inverter

25 Euros for DC - DC converter ...

QED

 

[Helina]

Re: 12 - 19V

The inverter was cheap anyway and the "salesman" recommended that I could find the inverter from an other shop even ! He told me that the power from the inverter through the original 220v would be smoother than f it comes directly from the 12v system . I'm no way a specialist but it works !

 

[finnlou]

Re: 12 - 19V

of course it works, but you were still conned.

 

[Helina]

Re: 12 - 19V

Maybe it's a finnish thing, to be blond....... /forums/images/graemlins/confused.gif

 

[alldownwind]

Many thanks for the replies and advice. Not really a problem at all, then!

 

[bluedragon]

Lots of people telling you to get a DC-DC converter...but a 150 or 300W inverter will mean you get power not only for this PC but anything else small that needs 240V. I've done this (150W inverter) and wouldn't be without it.

 

[fireball]

It depends on how long your using the laptop for and what capacity your ships batteries have.
General opinion is that an inverter is less efficient than a DC-DC converter, therefore if you are using the laptop as your main navigation tool and don't have bags of spare AH's then it may be prudent to go for the more efficient method of powering the unit.

 

[jerryat]

Yes, but the problem is that if you are trying to download wefaxes/RTTY via an HF receiver, the inverter 'noise' will wipe out the signal!!

This doesn't happen with a DC-DC converter, which are available for 19vDC output as requuired by many laptops.

 

[bluedragon]

I didn't know that (doesn't affect me though). Getting back to the efficiency issue...I've heard so many stories on this including that modern inverters are very efficient. So what are the definitive facts? Who has the data to back up these generally held opinions? With the PC battery out (so no energy wasted trying to charge a dead battery) I was using 2.5A at 12V through the inverter to power a modern 1.4Ghz laptop with screen on. With screen off this dropped to 1.8A. The inverter on standby (PC off) took 0.3A. This all seemed reasonable to me...

 

[Guest]

Energy efficiency ....

You could be right in that one is not more efficient than other .... but it is generally accepted that conversion of energy from one to another to another is less efficient than a more direct route - especially with electrical stuff - each step incurs a loss ... surely adding in the step-up to 240 and then step down to 19~ must incur a loss ?

But maybe the DC - DC converter incurs a greater los for what it does ?? Like you I have not seen actual figures to show ... but I am one of those who tends to believe that direct DC-DC is best ...