Laptop Power Supply

Submitted: Tuesday, Feb 09, 2010 at 22:46
ThreadID: 75910 Views:4790 Replies:10 FollowUps:8
This Thread has been Archived
Hi Gang

I bought a laptop mainly to use for mapping purposes. I have been looking on eBay at laptop power supplies, that run from the cig lighter socket. A couple of questions, as electricity an me are not even slight acquaintances.

1 Are they safe to use for a laptop ( I see a lot on here about pure sine wave inverters)
2 I have a Compaq, and the output on the 240v charger says output is 18.5v. All the cig lighter ones I have looked at supply either 18 or 19v (selectable), not 18.5. Which setting (if any) out of these 2 would be best to use?

Thanks for your help, Dave

Back Expand Un-Read 0 Moderator

Reply By: REV'S - Tuesday, Feb 09, 2010 at 22:59

Tuesday, Feb 09, 2010 at 22:59
Hi Dave,
there are leads that plug straight into your cig lighter. But it will be necessary to get the correct one for your computer. So its best to go to a computer supplier and get the correct one to suit your computer.

regards
Revs
AnswerID: 403502

Reply By: Geoff (Newcastle, NSW) - Tuesday, Feb 09, 2010 at 23:03

Tuesday, Feb 09, 2010 at 23:03
Hi Dave,

Young Dickie Smith sells a gizmo called a Kerio adaptor.

It comes with a ciggie plug, box in the middle and a plug to fit a laptop at the other end.

The Kerio has an insert looking for all the world like a fuse called a bias resistor. The bias resistor will give it the exact output voltage to match your laptop.

After all that semi technical rot, go to Dick Smith or probably Jaycar wit your laptop and look at Kerio adaptors.

Geoff,
Landcruiser HDJ78,
Grey hair is hereditary, you get it from children. Baldness is caused by watching the Wallabies.

Lifetime Member
My Profile  My Blog  Send Message

AnswerID: 403503

Follow Up By: Brakko - Wednesday, Feb 10, 2010 at 16:16

Wednesday, Feb 10, 2010 at 16:16
I would second the Kerio adapter. A lot better option than an inverter and a specifically made power source for computers.

Brak
0
FollowupID: 673150

Reply By: Member - Wayne B (NSW) - Tuesday, Feb 09, 2010 at 23:35

Tuesday, Feb 09, 2010 at 23:35
I have a Dell Lap top
I purchased a universal cig lighter plug in power supply that has variable voltage out put The laptop can take a couple of extra volts that should not hurt it. However it will only run the laptop, all day if you like, but WILL NOT CHARGE THE BATTERY.
I am told I have to get the correct one from Dell to charge the battery. Don't ask why I don't know.
Cheers
Wayne
AnswerID: 403506

Follow Up By: Geoff (Newcastle, NSW) - Tuesday, Feb 09, 2010 at 23:42

Tuesday, Feb 09, 2010 at 23:42
Wayne,
The charging is a Dell thing as you have been told.

There are some signals between the Dell power supply and the laptop Dell won't release to third party suppliers such as Kerio.

Yep, they will run and yes, they won't charge. Dell like it that way!

Geoff,
Landcruiser HDJ78,
Grey hair is hereditary, you get it from children. Baldness is caused by watching the Wallabies.

Lifetime Member
My Profile  My Blog  Send Message

0
FollowupID: 673005

Follow Up By: Zebra400 - Wednesday, Feb 10, 2010 at 05:27

Wednesday, Feb 10, 2010 at 05:27
I have a Dell as well. To run the 12 volt adaptor, Dell requires the wattage to be reduced from 90Wts to 60Wts. The adaptor does this.

Apart from things running a little slower, I prefer the adaptor to an 240 volt invertor.

Laurie
0
FollowupID: 673022

Follow Up By: Richard W (NSW) - Wednesday, Feb 10, 2010 at 07:44

Wednesday, Feb 10, 2010 at 07:44
I also bought the Dell 12v adaptor when I purchased my laptop.
0
FollowupID: 673023

Follow Up By: Maîneÿ . . .- Wednesday, Feb 10, 2010 at 10:29

Wednesday, Feb 10, 2010 at 10:29
Run my Dell direct from the 300 watt PSW Inverter on 240v and it recharges the battery at same time, because I take the laptop out with me and use it's battery often.

Maîneÿ . . .
0
FollowupID: 673047

Follow Up By: Dr Hook - Wednesday, Feb 10, 2010 at 11:21

Wednesday, Feb 10, 2010 at 11:21
THe Dell laptop AC adapter has an additional (core) wire to ensure you can only use Dell chargers with Dell Laptops.

The problem with (at least my modified sine wave) inverter, is that it provides an inconsistent charge, to the laptop and to the battery.
The battery will progressively die (mine just did and Dell charges $240 per replacement or $140 from elsewhere) as the battery manager reduces its charge capacity for successive charge and does so repeatedly when on the inverter - in effect your battery "ages" very quickly on the inverter.

In addition, my Motherboard developed a fault- no comment from Dell (they are replacing it free of charge) but a Computer Tech advises me that the modified sine wave inverter is probalby the cause - the motherboard was not recognising when the AC supply was plugged in, so no power to laptop and no re-charging of (even the new) battery.

If it wasn't so expensive to replace, I'd put the Dell in a sock, swing it round my head and let it go!!!!!
0
FollowupID: 673059

Follow Up By: Maîneÿ . . .- Wednesday, Feb 10, 2010 at 11:38

Wednesday, Feb 10, 2010 at 11:38
You say: "Computer Tech advises me that the *modified sine wave inverter* is probalby the cause" I think you will find he is correct too :)

It's not a Dell fault, but caused by the wrong charging method/device

Maîneÿ . . .
0
FollowupID: 673062

Reply By: Member - Damien L (Cairns) - Tuesday, Feb 09, 2010 at 23:48

Tuesday, Feb 09, 2010 at 23:48
I run my laptop through a 1000w inverta. I used to use a 600w but found it oo small as the charger drew 450w and it got too hot. The inverta I now use charges the battery as well.
Regards Damien
Love the bush

Lifetime Member
My Profile  My Blog  Send Message

AnswerID: 403509

Reply By: Ozhumvee - Wednesday, Feb 10, 2010 at 07:16

Wednesday, Feb 10, 2010 at 07:16
It is more electrically efficient (less power drain) to use a 12v power supply to run the laptop than use an inverter.
The inverter takes 12v and turns it into 240v, they aren't particularly efficient at doing this, in fact cheap ones can be down around 70%. Then the laptop power supply steps the voltage back down to the 18.5 volts for the actual laptop, again they aren't real efficient (all the later ones I've seen get pretty hot to the touch, heat equals wasted energy.)
I'm also very wary of having 240v in the car while travelling, under seats and around sharp edges especially if there are kids in the vehicle.
The Kerio units mentioned above has a good reputation.
What I did was to get a Kensington charger/power supply which has an adjustable output to suit your laptop and can supply the output from either 240v or 12/24v. So only one unit to carry/store instead of an additional 12v one.
They are a bit dearer than the Kerio style but being multivolt 110-240v are verstile for overseas travel as well.
I bought mine from Ebay/overseas as they were much cheaper.
Peter
1996 Oka Motorhome

Member
My Profile  My Position  Send Message

AnswerID: 403527

Reply By: Member - John and Val - Wednesday, Feb 10, 2010 at 07:43

Wednesday, Feb 10, 2010 at 07:43
Dave - Provided your laptop doesn't have a fancy power supply cable and multipin plug, has just a simple 2 pole connector (round, a centre contact and the outer shell) - any 12V to 18/19V adapter capable of supplying adequate current should do the job. The current rating will be given on your mains adapter. Either 18 or 19V should be fine.

I would certainly avoid using an inverter. With the above proviso, suitable 12V power supplies are readily available from Jaycar and similar places. They come with a range of connectors to fit various computers and it's easy to get these connectors wrong, so get the shop to set it up for you. (The critical thing is to get the + and - right way round. Could be very expensive if wrong!) Then araldite to be sure it stays that way.

HTH

John
J and V
"Not everything that can be counted counts, and not everything that counts can be counted."
- Albert Einstein

Lifetime Member
My Profile  My Blog  Send Message

AnswerID: 403529

Reply By: MrBitchi (QLD) - Wednesday, Feb 10, 2010 at 08:45

Wednesday, Feb 10, 2010 at 08:45
Jaycar sell a good unit with adjustable output voltage to suit your laptop and a number of different power plugs to suit different models.

Jaycar power supply

AnswerID: 403537

Follow Up By: farouk - Wednesday, Feb 10, 2010 at 10:21

Wednesday, Feb 10, 2010 at 10:21
Go to www.aubattery.com.au get thier email address and give them your laptop Model no and they will supply the RIGHT 12 v adapter, I have recently bought 2, one for a Toshiba and one for a HP netbook, both the same voltage but totally different adapters , Toshiba $43 HP $33 very fast service.
Farouk
0
FollowupID: 673045

Reply By: farouk - Wednesday, Feb 10, 2010 at 14:25

Wednesday, Feb 10, 2010 at 14:25
Furailther to previous post

mail address aubattery.com.au@gmail.com

Thr prices include postage of $10

Farouk
AnswerID: 403614

Reply By: Member - The Bushwhackers -NSW - Wednesday, Feb 10, 2010 at 15:26

Wednesday, Feb 10, 2010 at 15:26
Hi all,

Thanks to every one for your advice.

Guess the main theme is to get the right adaptor or problems could arise.

I will do the right thing, and go to the knowledgeable people for the correct equipment.

The charger that Farouk mentioned looks for all the world like the one on eBay.... just $65 dearer, however, as I don't understand this sorta stuff, I will go to Dickies or Jaycar.

Thanks again for the good advice,

Dave

AnswerID: 403630

Reply By: Ianw - Wednesday, Feb 10, 2010 at 23:19

Wednesday, Feb 10, 2010 at 23:19
I bought one off Ebay, cost around $20, works well. Battery is charged in half an hour, and can use lappy while charging. Handy when in the van out bush.

If it puts out the correct voltage, at the required current, then all should be well.

Ian
AnswerID: 403705

Sponsored Links

Popular Products (14)