[Macworld]

Post your comments for Finally, your laptop can charge your tablet here

[JMHammer]

It's a transformer. It probably boosts the voltage at the expense of the amps, allowing enough charge to trickle into the mobile device to charge it. Slowly. It's really not worth the $30 compared to, say, a simple AC to USB charging unit which can be had for much less and will actually charge a mobile device at a good rate. If you can plug your laptop into AC, you can plug your mobile device into AC. And if you're laptop is running off its own batteries with no AC available, you might as well keep your mobile device asleep and just use the laptop, which is a more efficient use of the power in its battery.

And for what it's worth, in my experience any Mac's USB ports deliver enough power to charge any iOS device as long as the Mac is ON and not off or asleep.

[PhilipK]

Agree with JMHammer. I always charge my iPad and iPhone with the MacBook Pro USB port.

[tiborg]

Even thought the iPad displays a not charging sign, if you put the iPad to sleep, it will slowly charge even if only connected to a usb keyboard.

[fithian]

If you are on a plane with the plane power adapter and not 110v, this would be a good solution. I can't think of any other use. If the plane has 110/220v an extension cord can be used to power all devices. I have used my MBP to charge iPhones even without any power to the MBP.

[tatilsever]

"Ah, but how?"

Yeah, pity, if only there was a journalist to ask that question and relay the answer to the readers.

[JakeRich]

"Finally?" I've always been able to charge my iPad with my laptop. As tiborg said, if you turn the iPad off, it will charge slowly on the USB port power. Always has. No "finally" here.

[wesley96]

Quote

It's a transformer. It probably boosts the voltage at the expense of the amps, allowing enough charge to trickle into the mobile device to charge it. Slowly.

No, this can't be the case. USB port must supply a constant 5V voltage - otherwise, it would fry the devices. You aren't providing trickle-charge voltage through USB port. The device receives a fixed voltage, which is then used to operate the charging circuit within.

The port nominally outputs up to 500mA of current, as per original USB specs, but iPhone can support 750mA and iPad, 2000mA. The wall chargers supplied with each of those products provide that much current.

In other words, this ChargrDr thing has to somehow manage to boost the current without dropping the voltage. It would have to somehow make the computer's mainboard to provide more current than it was originally designed to handle.

[jimlat]

Quote

It's a transformer. It probably boosts the voltage at the expense of the amps, allowing enough charge to trickle into the mobile device to charge it. Slowly. No, this can't be the case. USB port must supply a constant 5V voltage - otherwise, it would fry the devices. You aren't providing trickle-charge voltage through USB port. The device receives a fixed voltage, which is then used to operate the charging circuit within. The port nominally outputs up to 500mA of current, as per original USB specs, but iPhone can support 750mA and iPad, 2000mA. The wall chargers supplied with each of those products provide that much current. In other words, this ChargrDr thing has to somehow manage to boost the current without dropping the voltage. It would have to somehow make the computer's mainboard to provide more current than it was originally designed to handle.

[jimlat]

Quote

It's a transformer. It probably boosts the voltage at the expense of the amps, allowing enough charge to trickle into the mobile device to charge it. Slowly. No, this can't be the case. USB port must supply a constant 5V voltage - otherwise, it would fry the devices. You aren't providing trickle-charge voltage through USB port. The device receives a fixed voltage, which is then used to operate the charging circuit within. The port nominally outputs up to 500mA of current, as per original USB specs, but iPhone can support 750mA and iPad, 2000mA. The wall chargers supplied with each of those products provide that much current. In other words, this ChargrDr thing has to somehow manage to boost the current without dropping the voltage. It would have to somehow make the computer's mainboard to provide more current than it was originally designed to handle.

Oops...sorry for the double post...

Wesley...Ohm's Law... V=IR ....can't boost current without dropping voltage...they are inversely proportional...not sure how this thing works, but I'd be afraid of it's effects...slow charge with iPad off, or use it's charger/cable...

[HerbalEd]

Who would spend $30 on this thing? You don't need it. Calling the rather small AC unit that the iPad's USB cable plugs into a "brick" is a gross exaggeration.