Can you use the iPhone 240V (USB) Plug to charge other USB devices?

lancslass2008

Hi all

I have an iPhone. It is charged in any of these ways:

1. Car charger
2. USB on my PC
3. 240v Plug socket.

While I'm comfortable with Options 1 & 2, option 3 is a little confusing.

Basically, the White 240V style plug (that comes with your iPhone) that you plug into your normal wall socket is not just a White Plug with a lead that you plug the other end into your phone. It's a plug that you plug into the wall socket that has a small socket on the back that accepts a normal sized USB lead. So in effect, I'm guessing that this White plug somehow changes the Voltage from 240V to whatever voltage the iPhone needs. I assume this because if you pull the iPhone charger lead out of the back of the plug itself (while the main White plug is still plugged in to the wall) you can then just plug that lead into your PC's USB port, and the phone will continue to charge.

The reason why I ask the question is...

I am going to Spain soon and I will be taking my iPhone and the White 240V charger (Spanish plug adapter will also be used) to charge my iPhone in Spain. I am also taking a tiny MP3 player (Sandisk Clip) which doesn't take batteries (It charges from your PC's USB socket). So, I wanted to know if it's possible to simply pull the white lead out of the back of the White iPhone 240V charger plug and just replace that lead with the small USB charging lead for my MP3 player.

In effect I am charging up my MP3 player via the wall socket.

I'm sure that this 240V White plug that came with the iPhone must reduce the power to that of a USB Power because you can charge your iPhone from either this 240V Plug OR USB.

Any help please??

elvch01

It "should" work - there is little chance of blowing anything up, but its work checking the power output of the iPhone charger (probably written on the plug) and verifying (if possible) that it is the same or greater than the power requirements of the mp3 player. Alternatively - just flatten the battery in the mp3 player & try it before you leave for Spain

kwikbreaks

USB voltage is standard at 5v. If your iPhone works plugged into a normal USB port then the mains adaptor with the USB outlet must be delivering 5v too so should work with any other USB device. I'd be absolutely amazed if Apple have released a charger with a USB connector that doesn't adhere to the USB standard. Mind you Jobs seems to be a law unto himself.

epninety

There's no risk of damage, but it's worth testing that things do charge before you go away.

kwikbreaks wrote: »

I'd be absolutely amazed if Apple have released a charger with a USB connector that doesn't adhere to the USB standard.

That's missing the real issue - there's at least three 'standards' for charging from USB. There's no danger of damage from using the wrong one, but you need to check that's all your devices will charge, from that particular charger. And don't believe the 'charging' light either, wait and see if the battery actually charges up.

The problem is that the USB standard sets a limmit of 0.5A per USB port, which isn't enough to charge some devices, so they use tricks to figure out if they are connected to a charger or a PC, and change their current draw accordingly.

This is mostly for high power devices like mobiles and SatNavs, unlikely for a small MP3 players I would think, especially one that normally charges from a PC. I have a couple of Nokia phones that charge via USB from a PC or a 'dumb' slowly, but quickly from the correct charger (or any one that signals it's a high power charger). Also an HP SatNav (that uses a different signalling method) which only pretends to charge from a PC, while slowly draining the battery.

TimothyEBaldwin

kwikbreaks wrote: »

the mains adaptor with the USB outlet must be delivering 5v too so should work with any other USB device.

The USB standard requires devices consume no more than 0.5mA if sthere is no signal from the host, and no more than 100mA without explicit permission. The overall limit is 500mA.

Therefore simply providing 5V is not sufficient. Alas these rule are often ignored by power supplies and devices.