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Jackaroo
7th August 2008, 06:08 PM
Hi All

looking for a 12v, 3A power supply that I can plug into my ciggy lighter and power the eeePc

All the ones I have seen so far only accomodate 1.5 A

Thanks in advanced

JAckaroo :D

festy
7th August 2008, 06:12 PM
Don't know what plug the eeeeeePc has, but Jaycar were advertising a 12v voltage selectable 90w laptop PSU the other day.
I've been using their smaller one for a few years now, very happy with it.

Jackaroo
7th August 2008, 06:14 PM
Don't know what plug the eeeeeePc has, but Jaycar were advertising a 12v voltage selectable 90w laptop PSU the other day.
I've been using their smaller one for a few years now, very happy with it.

Will have a look but most of the voltage selectable ones start at 15v output and then go up. I need a 12V output, they do not seem to be very common

Jackaroo :D

festy
7th August 2008, 06:19 PM
you're right - that one starts at 15v.

The ones on ebay like http://cgi.ebay.com.au/New-Car-charger-for-Asus-Eee-PC-700-701-black_W0QQitemZ160268267169QQihZ006QQcategoryZ3151 0QQcmdZViewItemQQ_trksidZp1742.m153.l1262 appear to just be running straight off the car, but I don't know how the eeeeeeeeeepc would like 14v for too long.

Mr Router
8th August 2008, 04:09 AM
Just go the easy way and install a small, just for the EEEEEEE inverter :wave it's uncool to some to go dc to ac to dc but it cheap and works :hatoff The only noticeable is the power pack will run a shade warmer on modified sine.

Hoyks
8th August 2008, 02:17 PM
I was in Repco yesterday and they had a powerboard thing to mount in the car that had 2 ciggie plug outlets and 2 USB power outlets, if that is any help.

Mr Router
8th August 2008, 02:38 PM
Not really but sounds like a good bit of kit :hatoff

Marbelup
8th August 2008, 09:09 PM
Does the eeePC require EXACTLY 12 V? If there is some acceptable tolerance (e.g. up to 13.8 V = typical voltage for charging battery), then the cig lighter socket will supply pretty close to 12 V already (assuming you don't drive a truck) and 3 amps would be no problem.

From an electronics points of view, it is uncommon to find a voltage regulator to convert approximately 12 volts to exactly 12 volts, as you generally need a higher voltage to start with, or more complex circuitry to step up from a lower voltage to a higher one.

Nicko
8th August 2008, 09:44 PM
Usually the tolerance for electronics is up to 10%

Mr Router
9th August 2008, 05:52 AM
The EEEEEEEEEEE requires a power supply of 9.5 volts with a amperage of 2.315 or better

Nev
9th August 2008, 05:59 AM
The EEEEEEEEEEE requires a power supply of 9.5 volts with a amperage of 2.315 or betterSome - others obviously have 12VDC @ 3A.
http://www.eeeuser.com/2008/05/04/eeeusercom-eeepc-900-in-depth-review/
See photo under heading of Charger.

Mr Router
9th August 2008, 12:38 PM
The 900's up may be different havent read that yet ! The 700 is as i posted :hatoff

Mr Router
9th August 2008, 12:41 PM
Just read !

Marbelup
11th August 2008, 09:26 AM
The EEEEEEEEEEE requires a power supply of 9.5 volts with a amperage of 2.315 or better

Do the specifications mention a maximum value for the voltage?

What I am getting at is, will it work of the raw 12 V from the car which could be up to 13.8 V or even slightly more?

If it needs pretty much exactly 9.5 Volts this is a pretty tall order for an off-the-shelf unit due to the low differential between input and output.

An electronics hobbyist could make one using a low-dropout voltage regulator - which would work OK with the low differential between input and output.

Mr Router
11th August 2008, 04:39 PM
I would not like to go over rated 9.5, Referring to a previous post the inverter idea is by far the easiest option :hatoff Dont just buy the first one that pops up, you can get some really cool small ones :hatoff The one in the console of our Vitara is 150 watts and the same size as a packet of ciggies but a tad thicker, the power pack is under there to. Nothing needs screws to hold as it a neat fit all round, all cables come out to the control box which is velcroed to the carpet on the transmission tunnel in easy reach
Flick the switch on the controller and the plug in to the lappy to easy :mighty :mighty

Marbelup
11th August 2008, 08:07 PM
I was in Jaycar (Perth - Northbridge) today, and they had a unit which will accept 11-28 V DC and produce regulated 12 V DC at 6 amps.

The Jaycar part number is MP-3064.

Given a regulated 12 V output, a simple way to reduce this to 9.5 V would be use a series string of diodes, each of would would drop the voltage by approx. 0.7 volts.

So, 3 diodes would reduce by 2.1 volts to around 9.9.

4 diodes would reduce by 2.8 volts to around 9.2.

The choice of diodes is not crictical provided they can handle at least 6 amps.

The diodes would have to be assembled into a small box to prevent short circuits but this would be simple.

You can also substitute bridge rectifers which have 4 diodes connected internally, but provide a voltage drop equivalent to 2 diodes if you connect the -ve terminal of the first bridge rectifier to the battery +ve, +ve of the first bridge to the -ve of the second bridge, then the +ve of the second bridge becomes the +ve output for the PC. The AC terminals (~) of the bridges do not need to be connected. In this mode, the current rating of the bridge is doubled as the internal diodes are connected in parallel, so a 3 amp bridge would be needed.

It would be worth trying 4 diodes to start with and measure the voltage under load with a multimeter. If too low, go back to 3 diodes. The precise output voltage would also depend on how accurate the regulated 12 V is to start with.

If you use 2 x bridge rectifers and the voltage is a bit low, you can change to the equivalent of 3 diodes by taking the +ve output from both AC (~) terminals of the second bridge rather than from the +ve terminal. This way, the second pair of diodes in the second bridge is unused, but the first pair still share the load current.

Jackaroo
11th August 2008, 09:32 PM
I was in Jaycar (Perth - Northbridge) today, and they had a unit which will accept 11-28 V DC and produce regulated 12 V DC at 6 amps.

The Jaycar part number is MP-3064.



That little sucker is just what I have been looking for.

The eeePC 900 runs on 12v, 3A, so should be ample for what I need

Cheers

mob
31st August 2008, 04:33 PM
Marbelup,
you're a bleedin' legend. I spent a long, bloodshot eyed evening searching for that information with no success. I purchased an auto adapter with 9.5v @ 3a output on ebay. Good'n'cheap and worked a treat - for an hour and a half! :curse Very hard to find adapters with that output. Thanks a heap!

hownow83
2nd September 2008, 07:25 PM
I would not like to go over rated 9.5,


I can tell you for a fact that if you don't,it won't boot.Using a multimetre the output from this 9.5volt power supply is actually 10.5volts.At 9.5volts we barely got past the boot screen,let alone have enough juice to hold a charge.

Nicko
2nd September 2008, 09:03 PM
10.5v maybe under no load? was it connected to any device? It is not unusual for this to happen because the voltage will drop to 9.5v when under load as current is drawn. However, what this also means is that the design is designed around an inexpensive method rather than a quality design. If it works and there is nothing else immediately available then it's a great option.

The Explorer
2nd September 2008, 09:03 PM
Usually the tolerance for electronics is up to 10%

mmmm 9.9% more than my wife! Well the first one anyway.

Cheers
Greg

Nicko
2nd September 2008, 09:07 PM
That's because your wife is not made up of capacitors, resistors, transistors and ICs ;) In time you might be able to trade her in for a robot or humanoid. Long live Bladerunner!

hownow83
2nd September 2008, 11:32 PM
10.5v maybe under no load? was it connected to any device? It is not unusual for this to happen because the voltage will drop to 9.5v when under load as current is drawn. However, what this also means is that the design is designed around an inexpensive method rather than a quality design. If it works and there is nothing else immediately available then it's a great option.

It was during bootup.The only way i could get it to boot(homemade jaycar psu)was to up the volts to 10.5,which caused interference on the indash touchscreen.Dirty power i guess.I have ordered the asus car charger so i'll see how that goes.

johnno02
3rd September 2008, 12:34 AM
I dont own 1 of these devices,but looking around it seems the Battery voltage is around 7.4 volts,(Needs more than that to charge),of course.

I would suggest a WELL Regulated power supply.

Most Modern Electronics Devices,dont handle voltages going up,and Down,as load requirements change.

Another Major problem,is,if you lower the supply voltage,the device WILL draw more current,and possibly overload the supply.

For Ex,

If your device uses 35 Watts @12 volts,the current draw will be~2.9 Amps


Same device 35 Watts @ 9.5 Volts ~ 3.7 Amp Draw.

Forgotten a lot of the Electronics theory,its been a long time since I finished Tech.

Regards.
John

Nicko
5th October 2008, 12:20 PM
what type and size jack does the EEEPC require?

Nicko
6th October 2008, 12:36 PM
I received an email from a manufacturer and they said:

One question: After search in google, the output for Asus EEEPC model 900 is 7.2V DC not 9.5V. So could you please confirm the spec for such CLA and give me a forecast for the quantity. Then, I can give a precise price for you. 9.5V or 7.2V are both OK for us.


Anyone?

Jackaroo
6th October 2008, 06:34 PM
I received an email from a manufacturer and they said:

One question: After search in google, the output for Asus EEEPC model 900 is 7.2V DC not 9.5V. So could you please confirm the spec for such CLA and give me a forecast for the quantity. Then, I can give a precise price for you. 9.5V or 7.2V are both OK for us.


Anyone?

Just rechecked my adapter for the eeePc 900:

Input 100-240v 1A
Output 12V 3A

strange

Nicko
6th October 2008, 07:56 PM
So which EEEPC is Mr Router referring to? got a picture of the pin? Also what size is the pin?

Jackaroo
6th October 2008, 09:39 PM
Will try and get a pic of the pin soon, it is about 5mm OD with a 2mm hole in the centre.
Also pic of the power adapter