I was just thinking if you are on your computer anyway would it just use some of the excess electricity that your computer would have wasted or would it be worse than charging your phone from a charger while using your laptop separately.
It is a little bit more efficient, because your PCs Power Supply is not very efficient when you dont use much power. By using it more of it, it becomes more efficient, peaking somewhere at 50%. But: we are talking about very little differences here and only for Desktop PCs. When you use a Laptop, you Powersupply is way less powerful, so you use more of it by just using the Laptop. So in that case, i would rather use the charger. To be perfectly honest with you: All that is not realy worth thinking about. Its like opening your Fridge for only 6 Secounds instead of 8. Yes, its saves power, but there are petter ways to do so. Doing only 1 kilometer less with your electric car ist about the same as charging your phone 10 times.
I’d like to remind everyone of the “vampire effect” of wall-wart chargers - if you just leave them plugged into the wall waiting for you to connect a device, you’re constantly wasting a bit of electricity. That should also be involved in the efficiency decision of using the already plugged in computer or laptop.
Vampire effect was a real problem with older transformer-based wall warts. If you still have one that feels heavy and solid, or has a fixed energy rating on the label, this is you
If it feels light, almost empty, or the label has a wide range of frequencies and voltages, it uses an order of magnitude less and really doesn’t add up anymore. I believe it’s something like a couple cents per year.
Edit: found something from 14 years ago calculating the worst case scenario of leaving a wall wart plugged in as 7¢/month but I don’t believe it’s anywhere near that expensive for a modern one …. Although it’s probably more telling that I didn’t find anything more recent with a price estimate.
Someone correct me, but unless your charger is warm to the touch, this is a very insignificant amount of power a year.
Your TV pretending to be off probably draws more every couple of days.
Anything with a remote, anything with a screen, way too many “computerized” appliances. Leaving a computer on
If you care to minimize Standby power “comfortably”, usually libraries or power companies will let you borrow an AC Power Meter free of charge.
You can use that to inspect your various devices Standby Power. For example I have an amplifier that pulls nearly 15W in standby, since finding out it lives on a smart plug.
However my TV pulls less than 1W, and at that point I prefer the convenience of just being able to use the remote to turn it on.
(Also keep in mind with the smart plug solution that the plug itself will pull a little bit of power too, this will pretty much always be <1W though.)
Gallium Nitride based modern phone chargers are 95% efficient.
The very best, most expensive PC power supplies on 115v AC will only reach 94% at the very specific 50% load of power supply rated wattage. So if you have a 500 watt power supply, and aren’t using almost exactly 250 watts, you aren’t getting that 94% efficiency. Regular power supplies under normal variable load conditions are going to be somewhere in the 80% efficient range. If the PC is idle, that efficiency can drop to 20% (but it’s fine because it’s only a few watts).
https://forum.level1techs.com/t/super-high-efficiency-300-400w-psu/184589/2
So using a modern Gallium Nitride stand alone charger will be more efficient. It will be extremely more efficient if you use that stand alone charger instead of charging off your PC while your PC is idle.
Counter point. Most computer power supplies have a curve to their charging efficiency (somewhere north of 50% load). If your PC is substantially below the peak of that curve, then adding load (the phone) could raise the PSU’s efficiency say from 80 to 85% (I’m making up numbers) which would affect the overall efficiency of the entire PC’s load.
I think your answer is still probably correct, but it’s an interesting nuance to think about.
Side notes: Some PSU’s use gallium, e.g., Corsair ax1600i, though by and large most do not. Also if your in the EU then your working with 220/240v PSU’s which adds more efficiency, but that would apply to the phone charger as well.
Adding a 30 watt phone is going to be maybe 5% of the PC load. So it could bring it up to a few percent. But that is insignificant compared to the normal swings of 200+ watts between normal and load.
excess electricity that your computer would have wasted
Ya this is not how electricity or computers work.
Your computer doesn’t have “excess energy”
