IPad-3 Charging from my Laptop through USB cable

[Bosvaark]

USB ports don't produce a high enough output voltage for the iPad to recognise a charge, all the USB port is really for is the transferring of data, USB 3.0 is the faster that 2.0 for obvious reasons, think about it this way, the iPad has a 11,000 mAh battery, most laptops are around the 15,000-25,000 mAh range, with your laptops charger input being about 5v the laptop would loose charge almost instantly trying to charge an iPad.

The iDevice Guru

It's not the voltage , but the ampere rating is too low on a USB port, it requires 2 amps 10watts to charge IE: more power, that's why it takes so long is it is trying to trickle charge the iPad.

Some USB 2.0 ports and accessories do not provide enough power to charge iPad. When this occurs the message "Not Charging" appears in the status bar next to the battery icon.

On most USB ports the power spec is 100mA ,unless the device is configured for high power(charging port), then it is 500mA. The mother board bus voltage is 4.75v to 5.25v.

Laptop power supplies range from 15-20 volts and 3-7 amp rating depending on the size of laptop.

 

[iDeviceGuru]

It's not the voltage , but the ampere rating is too low on a USB port, it requires 2 amps 10watts to charge IE: more power, that's why it takes so long is it is trying to trickle charge the iPad.

Some USB 2.0 ports and accessories do not provide enough power to charge iPad. When this occurs the message "Not Charging" appears in the status bar next to the battery icon.

On most USB ports the power spec is 100mA ,unless the device is configured for high power(charging port), then it is 500mA. The mother board bus voltage is 4.75v to 5.25v.

Laptop power supplies range from 15-20 volts and 3-7 amp rating depending on the size of laptop.

Yes...? Are you trying to make a point or have a just missed it?

The iDevice Guru

 

[Bosvaark]

Yes...? Are you trying to make a point or have a just missed it?

The iDevice Guru

I was correcting what you said in your post as it is misleading.

" USB ports don't produce a high enough output voltage for the iPad to recognise a charge"
Incorrect : voltage is constant its amps that increase charging rate , in this case 100ma on a standard USB port is not enough hence the trickle charge


"with your laptops charger input being about 5v ...."
Incorrect : Laptop power supplies range from 15-20 volts not 5V

 

[Goavs18]

My Ipad3 charges through my MBP, I dont know the rate but it does charge and shows charging with the lightning bolt through the battery icon.

 

[coolstuffs]

Hi, my IPad-3 does not get charged from my Laptop, whereas, it only gets charged through 10W power cable. I would appreciate if anybody could give me the reason for not charging. Thanks

The ipad charger is guaranteed to supply your ipad a maximum energy of 10 watts at an operating voltage of 5V and a current of 2 amperes. That is 5V x 2 A = 10 W.
According to Wikipedia, USB 2.0 port operates at a voltage range from 4.75 - 5.25 V and the maximum current that can be drawn is 0.5A. Assuming a 5V operation, the
maximum energy that the USB 2.0 port can give is 5V x 0.5A = 2.5W. This is very small compared to the 10W given by the charger. It will charge your ipad but it will take
a long time to get a full charge condition. If you have USB 3.0 according to Wikipedia, it operates at 4.45 - 5.25 V and can supply a maximum of 0.9A. Again assuming a 5V
operation, the usb 3.0 port can supply energy at 5V x 0.9A = 4.5W. This is much better compared to usb 2.0 but is less than that of the charger.

 

[Mickeylittle]

I actually just bought a new laptop about a month ago for $350 from Best Buy that has totally blown me away. It is an Asus K53 and it has a USB 3.0 port but it also has a USB port that does what is called "Quick Charge" and it does charge my new iPad and will even charge it while the laptop is sleeping or turned off. This is a great feature and has come in handy on a couple of occasions while sitting in a hospital room with limited plug in accessibility.

So look for this feature when shopping for new laptops!

 

[scifan57]

I actually just bought a new laptop about a month ago for $350 from Best Buy that has totally blown me away. It is an Asus K53 and it has a USB 3.0 port but it also has a USB port that does what is called "Quick Charge" and it does charge my new iPad and will even charge it while the laptop is sleeping or turned off. This is a great feature and has come in handy on a couple of occasions while sitting in a hospital room with limited plug in accessibility.

So look for this feature when shopping for new laptops!

How long does a full charge take compared to the time it takes with the normal charger?

 

[Mickeylittle]

How long does a full charge take compared to the time it takes with the normal charger?

I haven't tested that as I've only used the charging feature 2-3 times and probably had 40-50% when I plugged it in to charge. From the little experience I do have it has seemed to work as good as the wall charger though.

 

[iDeviceGuru]

I was correcting what you said in your post as it is misleading.

" USB ports don't produce a high enough output voltage for the iPad to recognise a charge"
Incorrect : voltage is constant its amps that increase charging rate , in this case 100ma on a standard USB port is not enough hence the trickle charge

"with your laptops charger input being about 5v ...."
Incorrect : Laptop power supplies range from 15-20 volts not 5V

Yes I know all of this but it's much simpler to quote it the way I did as most people have no Idea what amps and ma are, not making a big difference as they're not in need to know the outputs, if they were I would've stated them. Thanks for the response.

The iDevice Guru

 

[coolstuffs]

I actually just bought a new laptop about a month ago for $350 from Best Buy that has totally blown me away. It is an Asus K53 and it has a USB 3.0 port but it also has a USB port that does what is called "Quick Charge" and it does charge my new iPad and will even charge it while the laptop is sleeping or turned off. This is a great feature and has come in handy on a couple of occasions while sitting in a hospital room with limited plug in accessibility.

So look for this feature when shopping for new laptops!

Gigabyte have a desktop that provide a similar feature. According to the spec their mb is capable of delivering 3X the current of a standard usb 3.0. This means that it is capable of charging a 13.5 W device. If this device is the Ipad 3 then the charging time will result to 3 - 4 hours based on my calculation. This is more or less faster compared to the Ipad 3 charger unit can provide.

 

[Breeodi]

Hi everyone im new to this whole thing jus purchased my ipad3 last week& it's been so complicated!!. Firstly does it mean I can't sync my iPad to my iTunes library since its not charging? Also i cannot see "my iPad" appear on my iTunes library.
Pls any advice wud be much appreciated. Thnx

 

[iDeviceGuru]

Hi everyone im new to this whole thing jus purchased my ipad3 last week& it's been so complicated!!. Firstly does it mean I can't sync my iPad to my iTunes library since its not charging? Also i cannot see "my iPad" appear on my iTunes library.
Pls any advice wud be much appreciated. Thnx

Your iPad should connect wirelessly, ensure you're signed in on both devices on the same email account, also ensure you're connected to the Internet on both devices.check that you've successfully and fully set up your iPad. Anything else just let me know, I'll do my best.

Add me on Edited by Moderator - No social network addresses, please read the forum rules for live support!

The iDevice Guru

 

[alan roberts]

Hi everyone im new to this whole thing jus purchased my ipad3 last week& it's been so complicated!!. Firstly does it mean I can't sync my iPad to my iTunes library since its not charging? Also i cannot see "my iPad" appear on my iTunes library.
Pls any advice wud be much appreciated. Thnx

To connect wirelessly to iTunes on your computer, you must have your iPad connected to the mains charger.
Took me a little reading to get it working.

 

[Breeodi]

Your iPad should connect wirelessly, ensure you're signed in on both devices on the same email account, also ensure you're connected to the Internet on both devices.check that you've successfully and fully set up your iPad. Anything else just let me know, I'll do my best.

Add me on Edited by Moderator - No social network addresses, please read the forum rules for live support!

The iDevice Guru

Thanx ideviceguru would try it!

 

[Breeodi]

To connect wirelessly to iTunes on your computer, you must have your iPad connected to the mains charger.
Took me a little reading to get it working.

Thnx Alan