Charging phone via a usb

rogerblack

DragonQ wrote: »

USB sockets can provide power when the PC is turned off. This is usually an option in the BIOS/UEFI of modern PCs, so you can turn it off to save a bit of energy. Probably 1 W or something.

Turning this off means you can't have the PC suspend deeply and be woken by the keyboard. Which can save a reasonable amount of power.

JamesMason_2

What you all fail to mention is that a USB port will run at about a half amp maximum. A charger however is usually rated at more, so will consume more power but take less time to charge. Assuming no loss in either either process through other factors (unlikely), then the cost will be the same.


James.

NowRetired

Are you saying that your USB sockets are 'live' when your PC is switched off?

Yes

How do you 'switch off'?

Same as everyone else I suppose, shut down shut down from the menu in windows 8


Or it eventually goes off by itself if I ignore it for a while.

prowla

A lot of PCs don't actually power off, and can do wakeup on LAN or power on on keypress.

Of course, powering on on a keypress requires the USB connection(s) to be live.

(Incidentally, it's important to know this if you are tinkering around inside the PC, especially if changing memory - you have to unplug from the mains to ensure no power.)

Cycrow

a PC thats switched off still uses power. You will have to switch it off at the mains, or from the PSU to stop it using power.

The amount of power it uses is minimal, i think mine uses about 2-3w when switched off.

NowRetired

a PC thats switched off still uses power. You will have to switch it off at the mains, or from the PSU to stop it using power.

The amount of power it uses is minimal, i think mine uses about 2-3w when switched off

That is what I have found, I have a plug in electricity monitor and my PC, whilst charging my mouse batteries, still uses less than a dedicated battery charger.

londonlydia

Your device battery will need the same amount of energy put in it regardles of how you do it. What varies is how EFFICIENT the charging process is to do so. A less efficient mechanism will draw more power as it will have greater waste.

In terms of charging from a laptop, your phone will be charging from the laptop battery, so you will be paying to recharge your laptop fully. My feeling would be that this is less efficient than modern phone chargers to be honest, as you are introducing an extra step between the wall plug and the device and bringing in new ineffciencies.

Also, you should bear in mind that for a lot of batteries, you are better off discharging them fully (so let them get very low) and then recharge them back up, rather than keeping them on charge continuously. Keeping it fully charged and still plugged in can make the battery 'lazy' and less efficient.

DragonQ

rogerblack wrote: »

Turning this off means you can't have the PC suspend deeply and be woken by the keyboard. Which can save a reasonable amount of power.

I think you'll find turning a PC off saves more power than putting it to sleep.

Even when not in use, my bedroom extension lead powers my PC (off but PSU switch is on), speakers (standby since main power switch is hard to get to), monitor (standby since main power switch is hard to get to), phone charger (always on as far as I can tell, since it's warm) and HDD dock (off I think). This uses something like 5-6 W. The simple solution which I employ is to switch off the extension lead at the socket, so all of the devices are properly off when I'm not using them. This causes no problems for any of the devices.

Cycrow

DragonQ wrote: »

I think you'll find turning a PC off saves more power than putting it to sleep.

depends what level of sleep you put it into.
sleep and suspend are different. Sleep requires more power, as it maintains the state within RAM which requires power to active. Whereas suspend saves the state to the hard drive so doesn't require power to keep running.

Sleep resumes quicker than suspend.

DragonQ wrote: »

Even when not in use, my bedroom extension lead powers my PC (off but PSU switch is on), speakers (standby since main power switch is hard to get to), monitor (standby since main power switch is hard to get to), phone charger (always on as far as I can tell, since it's warm) and HDD dock (off I think). This uses something like 5-6 W. The simple solution which I employ is to switch off the extension lead at the socket, so all of the devices are properly off when I'm not using them. This causes no problems for any of the devices.

My pc has a smart extension which everything is plugged into. so when the pc is turned of, it automatically cuts the power to everything else (all 3 monitors, speakers, etc).
So the only thing drawing power is the pc itself.

I also have one on my TV which cuts power to everything else like the home Cinema Amp, BluRay player, etc.

Only thing that stays on is the virgin Tivo as it still needs to be on to record

DragonQ

Cycrow wrote: »

I also have one on my TV which cuts power to everything else like the home Cinema Amp, BluRay player, etc.

Only thing that stays on is the virgin Tivo as it still needs to be on to record

Yes I do this too. My TV, AVR, Xbox 360 and Wii are plugged into an extension lead which is controlled by a power saving remote device thingy. They use zero energy when off and I use my AVR remote to turn them all on. My HTPC stays asleep (using 1.5 W) because it wakes in a few seconds rather than taking 30 seconds or so to fully boot.

My server is on all the time to record TV, which is my biggest electricity consumer when I'm away, probably aside from the fridge.