Does charging a mobile phone from a computer draw an extra power?

Question

There are USB power chargers out there for most mobile phones. Do they draw any extra power from the computer than using a computer without?

If they do, do they draw less power than a conventional chartger? If you are using your computer anyway, are they more enviromentally friendly than a conventional charger?

Answer 1

if you're charging from a computer, it draws slightly more power from the plug socket to charge the phone in addition to run the computer.

there's no such thing as a 'green' plug. they don't emit CO2 and things, so technically the computer one and the plug one are both environmentally friendly.

I'm not really sure whether charging from a wall or a computer would be quicker... I'm guessing the wall socket, though. since it has nothing else to power and stuff, so all power goes to the phone.

Answer 2

To charge a battery you have to have a voltage higher than the voltage of the battery in order to overcome resistance and fully charge it. IE 14 volts in your car to charge a 12 volt battery.

The power source or charger also provides amperage or "flow" which relates more to how fast it can charge.

Your wall charger is a transformer with rectifiers to change AC to DC then provide a certain voltage to the battery. The wall charger gives off excess energy from the process of inducing DC voltage in the form of heat. For this reason the computer probably uses less energy since power is already rectified and available as DC

when using the computer you may or may not be more efficiently converting power--but if you are using the computer anyway then probably so since the power supply is up and running anyway

The amp/hr rating or watt rating should be on all electrical equipment stickers or in the manual would tell ou for sure.

I would feel best saying the computer if you are using it anyway and the charger if you are not otherwise using the computer.

The total actual amount of energy to charge the battery will be the same either way --the question is which device is wasting more power in the process due the the induction/rectification process to convert the AC to DC

Answer 3

From experience, charging phones, any phone from a usb takes longer. It would then infer that the power it draws form the computer is not much compared to the A/C charger which is solely dedicated for that purpose.

I would want to think that the usb chargers are designed as ad-hoc solutions to charging incase you forgot your charger at home or you forgot to charge your phone overnight like some people like me do.

I am no expert, just drawing on my experience anyway.

I hope this helps, Good luck

Answer 4

Obviously it must use some power to put power back into your battery, and as battery technology is relatively inefficient, you're actually using more power to charge the battery, than gets put into it. That's the way of things - nothing is 100% efficient.

Answer 5

To charge anything is "Enviromentally UN-friendly", use your computer or the mains, your choice. You're still messing with our planet.

Answer 6

Messing with our planet my ****. It's MY planet.