momodot opened this issue on Jul 11, 2009 · 11 posts
momodot posted Sat, 11 July 2009 at 8:55 AM
I am convinced my laptop runs hot on some wall outlets and cold on others even though I use a surge protector. A person (albeit with a vested interest as my last laptop fried after I used it at his house where I went to clean up after a lightening strike shorted the electronically controlled electrical system and and the lightning caused an arc that blasted a hole in the wall and burned a hole right through a water pipe causing a flood when they were away!) tells me a laptop can't run hot or cold based on the outlet it is plugged into "because of the transformer and the fact that power runs first through the battery".... Anyway, my new laptop also seems to run hot or called based on specific wall outlets... is that possible?
ockham posted Sat, 11 July 2009 at 9:27 AM
Some houses have lower voltage than others. If the connections to
the mains, and the screw-down connectors in the breaker box, are loose or
corroded, the voltage in the house can be low when lots of things are running.
In that case the power will also tend to be noisy, with lots of 'static' imposed
on the pure sine wave. I'd think the laptop's power supply would run
warmer when the mains voltage is higher, but that probably depends on
the exact circuitry. (There would be a resistor between the charger and
the battery, and this resistor would be dropping slightly more voltage
when the input is higher. That's speculation!)
ockham posted Sat, 11 July 2009 at 9:40 AM
Oh..... you're talking about different outlets in the same house. In that case the
difference would be in the breakers rather than the mains, but the same basic
principle.
Of course your perception of cold and hot could also be influenced by the
room. If the bedroom is colder than the living room, the laptop will feel
hotter to you in the bedroom even if its own measured temp is always
the same.
ockham posted Sat, 11 July 2009 at 10:06 AM
markschum posted Sat, 11 July 2009 at 10:44 AM
It can be worth testing outlets , particularly in an older home. You can get voltage drops depending on the wiring and what else is on that circuit.
A voltmeter for 120 volt AC range or higher , and an adapter plug is all thats needed.
momodot posted Sat, 11 July 2009 at 10:53 AM
I don't know. That it is perceptual is certainly plausible... but I am not sure. I just switched from one outlet to another in this room. I have two identical chairs exactly three feet apart... the outlet nearest each are eight feet apart... one is on an interior wall that dates to maybe to 1978... the other outlet is on a newer interior wall and dates to 2002. I do not know the age of the base electrical system. The house was built in 1912, probably was rewired in the 1970's, and got a new "switch" breaker board in 2002. Plugged into the outlet from 1978 (the outlet is from that time - the wiring could be much older) the laptop keys were too hot to touch and I feared the machine would break... on the 2002 outlet the machine is slightly warm to my palm over the heat sink to the left of the touch pad and the keys are cool. I was watching an .avi off the hard drive and running no other apps then the .avi viewer and my web browser which I used only to make thes posts. There is no detectable change in the cooling fan function but the exhaust now does not feel hot where as before it felt too hot to touch. I have experienced this in other buildings though and with other laptops and my wife has mentioned her laptop seeming to run hotter on some outlets and cooler on others. It could be perceptual though... I wonder if my curiosity would lead me to try to buy some sort of thermometer just to check! Does anyone know from the technical point of view if different circuits in the same house could influence how hot a laptop gets?
ockham posted Sat, 11 July 2009 at 11:57 AM
Same room, then it's definitely not perceptual! And too hot to touch is definitely
not just a voltage difference caused by corrosion!
I'd say you have a ground fault in that 1978 outlet, and it really needs to be fixed
before it causes a fire or a deadly shock.
Or it could be wired across both ''hot" wires instead of from one hot to neutral.
This would give 220 V instead of 110. Again it urgently needs to be fixed.
ockham posted Sat, 11 July 2009 at 12:02 PM
Probably doesn't need to be said, but just for completeness:
In the meantime, don't use those outlets!
WandW posted Sat, 11 July 2009 at 12:10 PM
Laptop power supplies are generally regulated-my HP and Compaq supplies can plug into any outlet from 100 V to 240 V, (with the appropriate plug, of course), so the input voltage shouldn't matter. Look at the sticker on it to see what the range is.
Are you sure the "cooler" outlet is actually live? Perhaps it is dead and you are running on the battery there, and the processer is running slower and thus cooler...
EDIT or the "Hotter" outlet could be dead, and the fan is running less because it's on battery...
That should cover all scenarios! :laugh:
----------------------------------------------------------------------------------------
The Wisdom of bagginsbill:
"Oh - the manual says that? I have never read the manual - this must be why."
markschum posted Sat, 11 July 2009 at 12:19 PM
You can buy for less than $10 a outlet tester that will show if it is correctly wired with hot and neutral correct and ground connected.
Ockham is quite correct, do NOT use that outlet until it is checked .
pakled posted Sat, 11 July 2009 at 10:21 PM
plus (if true), the late 70s were the dawn of aluminum wiring, and they didn't figure out that the load-handling abilities required different gauges of aluminum vs copper wire, it was known to cause all sorts of strangeness.
Just as a check-off on the list of sypmptoms, you might give the fan in the case a shpritz of air; sometimes the dust will accumulate and act as a blanket, which can make the laptop feel hotter. Just a thought...
I wish I'd said that.. The Staircase Wit
anahl nathrak uth vas betude doth yel dyenvey..;)