Laptop DC Power Plugs

[Giblets]

Isn't it strange that despite laptops/netbooks being very mobile that manufactureres fail to supply or even offer 12v leads as well as 220v PSUs when so many of us would like to charge them in our cars which would make charging on a boat easy.
I really don't know how they can be truely called mobile devices if a 220v supply is needed to charge them.

I have just bought a 12v ciggy lighter type adaptor for my Samsung NC10 netbook for use on the boat from power4laptops but cannot get my head round 12v in and 19v out! Anyone care to explain?

 

[knightvision]

You laptop requires a certain number of Watts (power). Watts have a direct relationship between Amps and Volts. It is possible via some relatively simple circuitry to trade Amps (of which you 12v 110Ah battery has lots) for Volts (of which you laptop needs)

Hope that helps
Edmund

 

[Hydrozoan]

Interesting finds. Thanks for coming back. One thing to be aware of is that I managed to a 12V power brick with the large 7.4mm plug. However, it did not have any connection to the centre pin …

Thanks, that’s an important issue and I’d need to see if a brick with a centre pin output were available.

Isn't it strange that despite laptops/netbooks being very mobile that manufactureres fail to supply or even offer 12v leads ...

I did say to the HP/Compaq help chap that, grateful to him as I was, I was rather disappointed that they did not address the issue more fully. (He had directed me to some power bricks on eBay, but a quick look didn’t convince me that they would definitely work for me, as it wasn’t obvious that they had the small plug.) He will pass my message on to the product people.

If you have one correct plug for the lap top, cut the wire, add connectors to the cuts and to your dc/dc supply - sorted!

Effectively what was said back at post #5. Many people will though be understandably reluctant to interfere with their only known reliable supply …

That’s what I might do – but it’s complicated by not knowing the smart pin voltage * and indeed if it is just a ‘presence’ signal or – as some discussions suggest – more than that. There is quite a bit of rather confusing stuff about smart pins and charging/powering, and their slowing down laptops when malfunctioning. I’m proceeding with caution, not least as I could void my warranty.

I might still just go for an inverter, though at least one thread on this forum had differing views on the extent to which they are more inefficient than dc-dc bricks. I’m presuming that a pure sine wave type would not be necessary, though even on that subject there seem to be differing experiences.

Apologies for a long response, but as you’ve all been kind enough to take an interest and offer help I thought I’d pass on where I’d got to. It’s hassle disproportionate to the likely cost of any kit, but as theolddsalt says, surprising just how complicated such a seemingly simple thing can be.

* My digital voltmeter is on the boat, and the probes of my analogue one are almost too big to put down the middle of the plug, so I've yet to get a really reliable value!

 

[RichardS]

I've got two cheap inverters - 150W continuous / 300W peak - one Maplin and one Lidl both cheap (around £30 I think) and both charge all the family laptops no problem.

They are less efficient that the 12V transformer things but compared to the fridge not noticeably any worse than the cabin lights etc.

One advantage of a cheap inverter is that you can use it for loads of other applicances as well, provided you don't try hairdryers, although SWMBOs hair straighteners work OK.

Richard

 

[nigelmercier]

Many laptops, such as Dell, have a 1-wire chip in the charger that talks to the motherboard through the "spare" wire. I just get chargers on eBay that say they work with my model.

 

[Hydrozoan]

Many laptops, such as Dell, have a 1-wire chip in the charger that talks to the motherboard through the "spare" wire. I just get chargers on eBay that say they work with my model.

Thanks - that fits with the 'smart' pin on the HP/Compaqs doing more than just giving a 'presence' signal voltage. Yes, I'd happily get such a charger if one were available with the right tip, but I haven't found one yet and have had specific 'Noes' from several on-line compatibility checkers and one supplier contacted directly. And when one is available, I will now be looking closely at how fully it emulates the AC power supply - e.g. does it power and charge, or just the former.

 

[Catamaran]

For quite some time I've been using the kensington wall/Auto/Air adapters. They work with a variety of laptops and provide USB charging as well. Yes not cheap.. But reliable and provide consistent behaviour
http://www.kensington.com/en/gb/4470/33403eu/wall-auto-air-laptop-power-adapter-usb

+1

You will have to go a long way to beat Kensington for reliability IMO.

 

[LadyInBed]

Maplin also do sets of adapter plugs for pc's

 

[nigelmercier]

Try this, or the seller http://r.ebay.com/YsJtZc

 

[Hydrozoan]

Try this, or the seller http://r.ebay.com/YsJtZc

Thanks Nigel but wrong size tip I'm afraid at 4.8mm OD, 1.7 mm ID - mine is ca. 4.5, 3.0

I'm going to get a small inverter for now, and explore bricks/tips later.

But thanks again for looking.

 

[nigelmercier]

Thanks Nigel but wrong size tip I'm afraid ...

This seller does many different types.

 

[Hydrozoan]

This seller does many different types.

Thanks, most do I think but the problem has been the plug and smart pin aspect, with the new PC never being listed as compatible, and the right plug never being shown.

However, I think I may just have cracked it as this system for an HP Envy 17 laptop:
http://www.amazon.co.uk/Envy-17-J053EA-Compatible-Adapter-Charger/dp/B00RAF92HA
appears to have exactly the same small plug and output voltage. I'll check with HP support and/or the supplier tomorrow to see if it will do for mine, and (I hope) both power it and charge its battery.

Thanks again.

 

[Hydrozoan]

I've at last managed to check with HP UK (after much running around) and they say that any charger for the similar Envy and Pavilion models with the same new smaller plug size should work for my Compaq too. There are several 12V chargers with the right size plugs for them, and I'm getting one of these: http://www.coywood.co.uk/hp-pavilion-15-car-charger-for-90w-65w-45w-15572-p.asp having spoken to the UK supplier who says it should both power the laptop and charge the batteries.

Thanks to all.

 

[Voyager 5]

Hi guys, I know this thread is old, but in case someone is willing to answer, I have question:

do you think there is any advantage using an inverter vs. an adapter?
I am assuming one uses a laptop and may need to use it plugged in and also recharge the battery when not using.

I have read that inverters, depending on type of wave used (modified or pure sine) can create trouble with the laptop in some cases. Some inverters can be quite cheap, like this from BESTEK:
http://www.amazon.co.uk/BESTEK%C2%AE-Inverter-Adapter-charger-MRI1513U-UK/dp/B00HSGV1PW/ref=sr_1_6?ie=UTF8&qid=1448189163&sr=8-6&keywords=DC+to+AC+inverter+car+laptop

I was wondering if the adapters like the ones from Kensington instead, although more expensive, are totally reliable and hassle free, example this:
http://www.kensington.com/en/gb/4470/33403eu/wall-auto-air-laptop-power-adapter-usb#.VlGquV61Wpl

My curiosity is not so much on the single models that are around (there are so many), but more general: why use an inverter and why use an adapter - which one you have found easier to use in your experience, and less battery-discharging and less at risk of creating troubles with the laptop, if something doesn't work as expected.
The key goals for me are reliability and not damaging the laptop.

 

[theoldsalt]

I assume you want to use your laptop on the boat and run it from your 12v domestic batteries.

The best way is with this type of adapter which steps up the 12v to various preset voltages. Many laptops use 19v and these adapters can be set to 19v. This is what I use for my ACER.

http://www.ebay.co.uk/itm/like/1705...ICEP3.0.0-L&ff14=122&viphx=1&ops=true&ff13=80

They are supplied with various tips tofit most laptop power input sockets.

I would not recommend using an inverter to create 220v for running the laptop.

 

[Voyager 5]

I assume you want to use your laptop on the boat and run it from your 12v domestic batteries.

The best way is with this type of adapter which steps up the 12v to various preset voltages. Many laptops use 19v and these adapters can be set to 19v. This is what I use for my ACER.

http://www.ebay.co.uk/itm/like/1705...ICEP3.0.0-L&ff14=122&viphx=1&ops=true&ff13=80

They are supplied with various tips tofit most laptop power input sockets.

I would not recommend using an inverter to create 220v for running the laptop.

That's quite cheap in comparison with the Kensington, I wonder why. By the way I have a Sager/Clevo laptop in case someone knows specifically compatible adapters.

I am also curious about this: why do you think is a bad idea to create 220v with an inverter. I am a total newbie on the subject, so I am interested in your opinion.

 

[Hydrozoan]

Gosh - the thread has come back to haunt me!

I agree with theoldsalt, and once I'd managed to sort out the tip compatibility problem, the new power supply (my third over the years, to cope with different laptops) worked impeccably all summer.

Edit: Your second post crossed with mine, and though addressed to theoldsalt I'll just add this: it has always seemed likely to me to be more efficient to go from 12V to (say) 19V in one step, and it's physically neater with one less bit of kit to go wrong. Also, whilst some people say they have run a laptop off an inverter with no problem, others have reported difficulty. The only advantage of an inverter seems to me to be the facility to use it for other (low-power) things, but many dc-dc power bricks have tips or a separate output for mobile phone charging anyway - or one can use a USB system from the laptop.

 

[Boo2]

Is there anywhere one can get laptop power plugs with simple wire tails?

Ebay or Maplin.co.uk search "power tip" or "male barrel connector". Don't know where you can buy them with wire tails attached though, sorry.

Boo2

 

[duncan99210]

I used to use a Maplin 12v to 19v dc supply box but found that the connections between the output and the various tips became useless after a bit. I already had a small (150 watt) inverter which I have now hard wired to the battery which I use to power the laptop when required. I also use it to power the printer when required. No idea if it's more or less efficient than the 12v power brick but it certainly works more reliably than the brick.

 

[Hydrozoan]

Ebay or Maplin.co.uk search "power tip" or "male barrel connector". Don't know where you can buy them with wire tails attached though, sorry. ...

Thanks, Boo2, but this is an old thread resuscitated - I'm now happily sorted as noted above.