Powering an ASUS EEE

[ian-and-penny]

I know my Asus runs on 12V but is it safe to power it from a car lighter socket? Charging voltage can get to 13.8 volts, so I was wondering if this sort of voltage can damage the unit.

What sort of power supply do others use?

[Papa Bear_Left]

I bought a cheap adaptor for less than I'd've paid for the bits to make my own, and it seems to work fine.

If the EEE (1000H in my case) is quite run-down, the adaptor has trouble supplying enough current if it's running, but will charge it up OK if it's off or in standby.

I haven't opened it up to see if there's any actual circuitry in there, but at the price I assume it's not much more than a series diode and a fuse!

[Guest]

I know my Asus runs on 12V but is it safe to power it from a car lighter socket? Charging voltage can get to 13.8 volts, so I was wondering if this sort of voltage can damage the unit.

Dunno about the EEE PC specifically, but I suspect it's being used in a lot of boating and automotive uses, but all electrical and electronic devices are usually made with a safe working variation of +/- 10% in mind.

If you want to see how much the regular power grid varies by a thingy from jaycar, about $40 I think, currently the 240V grid is supplying about 256V but it varies down to 230v at times too, ever wonder why fridges blow up?

Although 12 + 10% = 13.2v I'm not sure what alternators throw out, thought it was about 13.2 not 13.8?

[Papa Bear_Left]

Although 12 + 10% = 13.2v I'm not sure what alternators throw out, thought it was about 13.2 not 13.8?

Nope, 13.8V is the usual charging voltage for a 12V lead-acid battery

[Guest]

Although 12 + 10% = 13.2v I'm not sure what alternators throw out, thought it was about 13.2 not 13.8?

Nope, 13.8V is the usual charging voltage for a 12V lead-acid battery

Oh that's right, and where it gets weird, physics dictates the maximum charge per cell based on temp, the hotter the air temp, like in say an engine bay and/or the battery the lower the charge you can actually get a battery to. After tripping over the maximum charge you start producing oxygen and hydrogen from electrolysis and well yea, no smoking round battery charging, especially those quick chargers

Something else comes to mind about alternators only putting an 80% charge in batteries to reduce the risk/chance of electrolysis occurring, too long ago and the exact numbers allude me.

[Crisp image]

Yes the charge voltage is (or should be) 13.8V. If you measure the output of your adapter you will find it to be higher under no load. But when it is loaded the voltage will drop to about what it says the output should be.
Automotive electrical systems are able to copewith theese voltages with most items specifiying max V in as about 14.5-15V
Merry Christmas
Crisp Image (ex autoelec)

[Big Matt and Shell]

I've gone the other way and we use a DSE 300W inverter and charge it using mains power. We have had no problems to date...


(Edit: inverter is only 300W)

[Guest]

I've gone the other way and we use a DSE 500W inverter and charge it using mains power. We have had no problems to date...

Pure sine wave output?

If it's not it supposedly can damage AC equipment because of the sawtooth output produced.

[Big Matt and Shell]

I've gone the other way and we use a DSE 300W inverter and charge it using mains power. We have had no problems to date...

Pure sine wave output?

If it's not it supposedly can damage AC equipment because of the sawtooth output produced.

<P>A quick Google shows it as a modified sine wave inverter, Like I said no issues to date... I have run two different laptops on it so far. I suppose that's why you should insure your electrical devices.

[Mr Router]

Big Matt the only problem is that the lappy supply will run a little hotter when on the inverter The average lappy will draw around 90 watts from the supply, roughly 7.5 amps from the car, ROUGHLY We have an inverter built in under the console of the Silver Bullet about twice as thick as a ciggy packet and about the same shape, it's 150 watt and runs fine.
It is hooked to another power pack for Max(the lappy) which is under the console as well
No more saying better charge the lappy to find the charger at home

[Big Matt and Shell]

Kinda makes you wonder what you did without it! The added bonus is being able to charge GPS batteries, mobile phones etc without having 300 different DC adaptors... you just use the one you would normally use. Great for holidays as well.

[gibbo003]

modified sine wave inverter are killers of ac moters but shouldnt be a problem for laptops. We use one on our boat to run a large fan which we know will harm the fan over time but they are cheap. When its working you can hear a strange hum coming from the fan.

[Guest]

The average lappy will draw around 90 watts from the supply, roughly 7.5 amps from the car, ROUGHLY

Depends on the type of lappy, an EEEPC will chew bugger all, where as those desktop replacement laptops chew 120W+...

[Guest]

Kinda makes you wonder what you did without it! The added bonus is being able to charge GPS batteries, mobile phones etc without having 300 different DC adaptors... you just use the one you would normally use. Great for holidays as well.

Yes I've had an invertor wired into my car since 2004 for my other hobbies in the past, but the cost is wasted power going up in heat when you go from 12v to 240v and back down to 5-19v and a flattend battery if you leave the invertor running (ie bypass the ignition), the little LED will flatten my battery in about a week or so. Then again the car alarm LED does the same in about 5-6 weeks too.

[Guest]

modified sine wave inverter are killers of ac moters but shouldnt be a problem for laptops. We use one on our boat to run a large fan which we know will harm the fan over time but they are cheap. When its working you can hear a strange hum coming from the fan.

I haven't had an issue with laptops and invertors either, but the generator companies like to advertise otherwise to sell higher ticket items etc.