Laptop power - 12 volt adapter

Submitted: Friday, Jan 28, 2005 at 02:51
ThreadID: 19849 Views:3490 Replies:8 FollowUps:3
This Thread has been Archived
One for you electronic gurus,

Just bought a Sony Vaio B series laptop computer.

Also bought a Targus 12 volt adapter to be able to run it in the 4by. $160.

Plugged it all up to 12 volt with the right tip and all and it won't go. Computer does not recognise it as an AC power source. Tried it in a Toshiba laptop and it worked just fine.

The output of the adapter says 16 to 24 volts and up to 70 watts. The input to the Sony laptop says 16 volts and 4 amps but does not specify a wattage.

I seem to remember that you get watts by multiplying the volts by the amps or something similar. If this is correct then the computer wants 64 watts which is nearing the capacity of this adapter. Maybe the adapter is not big enough to run the computer. Am I right in thinking this???

Annoying when the salesman says "This is the product you need Sir" and you get it home to find it won't go.

If anyone can recommend any alternative products for powering the laptop in the 4by I am all ears. How much less efficient is it to run a small (say 150w) PSW inverter instead? Is that all the power supply is anyway?

Back Expand Un-Read 0 Moderator

Reply By: Member - Sand Man (SA) - Friday, Jan 28, 2005 at 04:21

Friday, Jan 28, 2005 at 04:21
Hi Muddy,

Your calculations are correct. I think you may be right re the capacity reaching the upper limits of the adaptor output.

I'm not familiar with the Targus adapter but suggest you try contacting Dick Smith's and enquire whether a Kerio Adaptor may be suitable. (They may be available elsewhere as well.)

The Kerio packaging lists the brands/models of computers supported by the particular unit (I think there is more than one).

The adaptor is a good idea as they are compact.

Your only other choice is an Inverter but the size of this unit, plus the normal Laptop power supply makes for a bulky and messy solution, compared to the Kerio (or equivalent)

Hope this is of assistance to you mate.

I'm diagonally parked in a parallel Universe!

My Profile  My Blog  My Position  Send Message

AnswerID: 95304

Reply By: Nick R - Friday, Jan 28, 2005 at 08:29

Friday, Jan 28, 2005 at 08:29
Hey muddy,
An inverter would be a cheaper option, I got a msw (not psw) 300w inverter on ebay for $75. It runs my stone age laptop fine, mine pulls 1 amp at 240v therefor 240 watts.
msw inverters are about half the price of psw, something to do with the output current quality, I don't really understand it but don't intend on using much more than the laptop on it anyway.
Carpe Cerevisi

Lifetime Member
My Profile  Send Message

AnswerID: 95318

Reply By: Member - Melissa - Friday, Jan 28, 2005 at 09:28

Friday, Jan 28, 2005 at 09:28
Hi Muddy,

We went the Kerio adaptor route to run our old Digital laptop and it worked fine. Then we replaced the Digital with a new NEC Versa and found the Kerio won't run it. We're a bit sick of buying 12V adaptors to suit every individual bit of electronic gadgetry that we can't seem to do without these days so we bit the bullet and bought a 300W modified sine wave invertor from Dick Smith. Cost about $125 I recall. Anyway, it not only runs the laptop, we now also use it to recharge mobile phone and digital camera so its versatile. Incidently, we just bought a "lesser" laptop (an Acer, $1269 from BigW. Boy have laptops come down in price!) to take away with us rather than the "good" laptop and whilst the Kerio adaptor will run the Acer, we'll stick with using the invertor.

If it was me, I'd take your Targos adaptor back to the shop on the basis that it doesn't do what the salesman assured you it would and spend your money on an invertor instead. Hope this hopes.

:o) Melissa
AnswerID: 95328

Reply By: Big Kidz (Andrew & Jen) - Friday, Jan 28, 2005 at 09:29

Friday, Jan 28, 2005 at 09:29
Hi ya Muddy boy!

I ran my Vaio on a 300W Dick Smith Inverter but the power pack thingy made more noise than when on the mains and it got quite hot and and would overload the Inverter which made it cut out. I ended up settling it to a friend and bought a pure sine wave inverter and now it doesn't buzz or get hot. It was not happy on the cheaper inverter and I was worried that it was going to burn itself out.

AnswerID: 95329

Reply By: Gerry - Friday, Jan 28, 2005 at 09:31

Friday, Jan 28, 2005 at 09:31
Even if you are reaching the limits of the power adapter, it will still charge the batteries of the laptop with it switched off so you should see power getting through. Are you sure you have the correct tip? I had a Compaq once where I had to trim off a bit of the plastic on the tip to enable it to go in far enough to make contact.
AnswerID: 95330

Reply By: Leroy - Friday, Jan 28, 2005 at 09:34

Friday, Jan 28, 2005 at 09:34

Targus are probably the best 12v power supply for laptops around. Used them heaps for our sales reps in a previous job and I have one I use on my thinkpad all the time. I would go back to the shop with it and get them to test it or give you another. You could test your adapter with another laptop also. Good luck.

AnswerID: 95332

Follow Up By: Muddy 'doe (SA) - Friday, Jan 28, 2005 at 22:55

Friday, Jan 28, 2005 at 22:55
Thanks Leroy,

Yes I tested the adapter on a Toshiba M30 laptop that I have here also and it worked without problems. I think it is just a case of the correct tip not being available yet.

FollowupID: 354209

Reply By: Member - Craig M (NSW) - Friday, Jan 28, 2005 at 12:44

Friday, Jan 28, 2005 at 12:44
Just a thought on the use of inverters, in the latest DSE cattldog it states that running a laptop continuosly on the standard inverters (cant think of there name) will damage the battery and end up stuffing it. It is okay if it is only every so often.
I bought a Dc adaptor from our local Leading Edge Electronics store for about $90 but havent got round to trying it out, I guess I better give it a try and make sure its strong enough.

AnswerID: 95381

Reply By: Muddy 'doe (SA) - Friday, Jan 28, 2005 at 21:40

Friday, Jan 28, 2005 at 21:40
Hi All,

Many thanks for the replies and advice.

After a bit of consideration I have decided to go for a 300W pure sine wave inverter from DSE (cat number M5113) for $294.

This is partly because it seems the easiest solution but also I have a digital camera that can only be recharged by 240v so it will handle that as well.

AnswerID: 95446

Follow Up By: Member - Craig M (NSW) - Friday, Jan 28, 2005 at 22:33

Friday, Jan 28, 2005 at 22:33
Went and tried out the adaptor for the laptop and it seems to work fine. Now going by the calculations mentioned above my laptop says 20v and 4.5 amps so that equals 90watts right ?
My adaptor only goes to 70watts but it runs fine so I think that maybe you had either the wrong tip or the tip was plugged in the wrong way round as it has tobe the right way to get the positive to the centre or the outside which ever the laptop needs.

FollowupID: 354202

Follow Up By: Muddy 'doe (SA) - Friday, Jan 28, 2005 at 22:52

Friday, Jan 28, 2005 at 22:52

I think it IS a tip problem with my adapter as the specific model of laptop is not actually listed on the Targus compatibility chart. The Sony B series is the successor to the Z series and I was using the tip recommended for that. Seemed to fit but was not doing the biz. Did not want to muck with it too much for fear of doing damage.

I have decided to go for the inverter as it gives me more flexibity to run other devices as well as the laptop. That is not to say that the 12v power supply could not have been used, maybe with another tip.

As to your 90 watts out of a 70 watt power supply, just be careful that you are not starving the laptop which may lead to shortened battery life. There seemed to be a few comments about this.

FollowupID: 354206

Sponsored Links

Popular Products (11)