External monitor increses/decreases battery life

I do,'t know if this is the right forum for this question but i really didn't know where to post this Q.

So, when you have an external monitor plugged in and therefore do not use laptop's monitor will that improve the battery life or not? I have seen a few version of "tips to save power" which advise you to unplug the monitor - why? Is there something else going on there that drains the battery even more than the laptop's display.

 

Using an external monitor with its own power source should increase battery life as the laptop screen is one of the biggest draws of power for a system. Not sure if there are any increases in power due to increased GPU load but you can always test it out...

 

Actually I cannot just yet

I am split between two subnotebooks, the main difference (at least for me) between them is battery life. While at work I will have an external monitor (with its own power source) plugged in. So this is a big issue for me.
I will most certanly not opt for the notebook with the weaker battery life if external monitor will decrese it even more, even though there is a substantial difference in price.
On the other hand I would feel stupid if I bought the more expensive one if either would be good enough.

 

On my laptop I don't get anymore than 2 hours on battery while using the built in screen, but running an external one has gotten me at least 3 hours when just using and external screen with 1920x1080 resolution. I didn't notice much of a difference using both screens at once compared to just the laptop screen though...

Don't ask me why I tested that myself.

 

I don't think there will be any additional GPU load. GPU is still running and rendering the images. Only the output paths are changing.


--

 

A higher resolution external screen could offset the benefit by increasing gpu/cpu usage. Either way you should see an increased battery life.

 

I'm sure this is a dumb question, but if you have a place to plug in an external monitor, why wouldn't you plug in your notebook as well?

 

Not dumb at all. I want carry around as little as possible. No cables, no external HDDs, no mice, just the notebook. There is just so much you can fit into a womans purse. I do not want to carry around another bag just to fit in all those things.

 

Well, in that case, you might want to see if either of them has a provision for a docking adaptor. It's not especially likely unless it's a business machine, but if it has one, or can connect to one, then you can charge your notebook at the same time as you're using the external monitor. Apart from that, the main reason that a lot of guides on saving power tell you to unplug electronics is because a lot of them still draw power even when they're "off", to help keep them warmed up so they can start faster. Unplugging them obviously keeps them from draining this power.

 

This would only really hold true for 3d rendering & gaming where higher resolutions do indeed cause much more load on a GPU depending on game settings. However in a regular 2D desktop environment a higher resolution would have minimal impact.

 

... why not just buy another power adapter ($20-40)?? it is very convenient to have a power adapter always in one place, ready to be used.

 

Of course, or you are using an older machine with heavy flash websites. I was just saying it is possible to see some increased GPU/CPU usage, but I highly doubt as much power draw as the internal screen.