Join 3,495 readers in helping fund MetaFilter (Hide)


Can laptops run hotter or cooler depending on outlet?
May 4, 2014 12:06 PM   Subscribe

Hi. I notice my laptop runs hotter at home than at another location. Might it be that outlets or electricity cause variation?

I'm aware of cooler rooms, hotter ones, less airflow, those factors... But I worry and am trying to test things. Seems this thing is hotter at home here than it should be taking all things into account. Thanks.
posted by noelpratt2nd to Computers & Internet (12 answers total) 1 user marked this as a favorite
 
No. The laptop power adaptor (which sits between the wall and the laptop) provides the same regulated voltage output to the laptop regardless of what's going on in the wall socket - you can even plug it into a 240V socket on the other side of the world and the laptop will see no difference. Something else must be the culprit :)
posted by anonymisc at 12:29 PM on May 4


Guess it is the warmer room, then. Just feels like a bigger diff. than it should be. Thanks.
posted by noelpratt2nd at 1:11 PM on May 4


Wow, I just checked again -- felt under the laptop. It's hot, and over a larger area than I'd have thought. I'm thinking maybe the marbley table it was on the other day made it feel more cool-? And now, I'm going to try removing the lap caddy it sits on here in the apt. Maybe it'll cool down a bit. Anyone ever heard of the material underneath, on which it sits, being a factor? I mean, the caddy I've had for years and there is air between it and the lappy. Time for more ventilation as things warm up here in D.C., too...
posted by noelpratt2nd at 1:16 PM on May 4


Sorry, just one other thought: What about the size of the adapter? Do the larger ones they used to come with make things hotter than the smaller ones? I have a Dell Inspiron 1525 and access to both sizes.
posted by noelpratt2nd at 1:27 PM on May 4


Different Dell power supplies put out different wattages. More importantly, they sometimes have different output voltages, which can damage electronics, so if you're not paying attention to such things I highly recommend not using different power supplies than what came with your device. Size does not necessarily indicate larger capacity, the writing on them does.

I suspect the difference you're noticing is differences in airflow in the cooling system.
posted by Candleman at 1:46 PM on May 4


It's unclear - if you're using a different adaptor at home, it could be outputting a higher voltage than the adaptor you use elsewhere, requiring the laptop's internal regular to dissipate more heat. First thing to check is the specs written on the adaptor - if one says it's output is, say, 18V DC, and the other says 19.5V DC, then that difference could cause different heat, though I wouldn't expect it to be much. If they both claim to output the same voltage, then you'd need to use a multimeter if you wanted to check for yourself.

If the amps the adaptor outputs are quite different, then the laptop might be using the extra power to charge the battery a bit faster, which would cause more heat but only until the battery was charged.

A simple test - use the same power adaptor both places.

The usual culprit for heat difference is the software or different kinds of activity (e.g. games at home vs word processing at work, DVD playing vs web, etc).
posted by anonymisc at 1:48 PM on May 4 [1 favorite]


Both adaptors (one larger, one smallish) are the ones from Dell for this lappy and are 65W. So that should take care of that. Thanks bunches to you all. I will say that taking away the caddy (some kind of plastic material) and letting it sit on this wooden desk has brought the temp down a fair bit.
posted by noelpratt2nd at 1:52 PM on May 4


The usual culprit for heat difference is the software or different kinds of activity (e.g. games at home vs word processing at work, DVD playing vs web, etc).

I've had a lot of Dell laptops over the years, and it's been pretty consistent that the cause of them running hot is usually doing something graphically demanding. In particular, Dell laptops that have a separate graphics card generally run the desktop and non-graphically-demanding applications off the built-in Intel graphics and only fire up the graphics card when they need to. Anything which causes the computer to fire up the "real" graphics card will almost immediately make it start to run noticeably hotter.

If you're still having problems with the heat, you can look into getting a laptop cooling pad; they're basically just a plastic caddy/lapdesk but with a few built-in fans (USB powered) to help disperse the laptop's heat. They do their job, but look at reviews online before you buy one, cheap ones tend to break quickly and/or be very noisy.
posted by mstokes650 at 2:06 PM on May 4


Okay, thanks. As far as the graphics, really I just play music, have an USB DAC headphone amp plugged in the laptop now, that alone. Incidentally, I'm for the first time running past my lame soundcard and into some computer speakers for lots better, or at least more consistent, sound. I have another Inspiron from 2012 (this one from 2007) and it runs cooler with anything. There's an extra adaptor I have that's 90W, should I just avoid it? It wasn't bought directly from Dell, though I was told it would serve my purpose.
posted by noelpratt2nd at 2:15 PM on May 4


There's an extra adaptor I have that's 90W, should I just avoid it?

If the output voltage is the same, and the output current (amps) is the same or greater, then I wouldn't hesitate to use it. Ignore wattage though, it's the volts that need to match. (Watts means volts x amps, so 90W supply could mean 4.5A at 20V, or it could mean 5A at 18V, etc. The laptop only draws as many amps as it wants up to the maximum the adapter can provide, but the voltage put out by the adapter is forced on the laptop.)

I'm actually more blase than that about using different power supplies - if they're within a volt of spec I'll use it, and even if the current is 2/3rds of what's required, that's ok - the full available current is only needed when things are maxed (battery charging at the same time as CPU and GPU and DVD running high etc), so when running on an underpowered power supply, I just don't max the laptop. My first laptop (11 years old) is still going strong, but that's just anecdotal.
posted by anonymisc at 2:32 PM on May 4


Okay, the final story is this: That extra adapter is 19.5V, same as my other two, but whereas the others are 3.34A, the one extra is 4.62A. They've all worked well for a few years now -- probably all (still) interchangeable is my guess. Confirmed?
posted by noelpratt2nd at 2:49 PM on May 4


Yes, that's fine. Since the laptop is designed to run from a 19.5V 3.34A supply, a 19.5V 4.62A supply means the laptop will run fine, and won't come close to taxing the more-capable adaptor.
posted by anonymisc at 3:09 PM on May 4


« Older What do modern-day students in...   |  I would like to move to NYC bu... Newer »

You are not logged in, either login or create an account to post comments