Why is Charging iPad via iTunes/MBP so Slow Compared To Wall Outlet?

[HappyDude20]

I've tried charging the iPad both ways; through the wall and when connected to my Macbook Pro and when its connect to my MBP its very slow to charge. Last night it was at 40% charge and forty minutes later it was barely at 42%.

Of course when hooked up to the wall its a different story...

...but what gives?

Side note: How long does it take for the iPad to charge completely? Or even to 80% like all previous iPods?

 

[miles01110]

Because USB ports don't have the same power rating as the wall adapter.

 

[HappyDude20]

Because USB ports don't have the same power rating as the wall adapter.

Ah, makes sense.

Dammit, guess I gotta keep waiting for that dock/keyboard to come out.

 

[ugp]

My iMac will charge the iPad with screen on but the charge time is slow. I plugged it in for the first time to the wall last night and it charged up pretty fast. I love that fact that I can go all day using this on the web and watching movies without having to recharge it during the day.

 

[diabolic]

The users guide tells you to plug it into the wall to charge, and USB to sync.

The charge time is directly related to the extra-long battery life.

 

[indy1979]

The charge time is directly related to the extra-long battery life.

Charge time is directly related to the output power of what it's plugged in to.

2.5 Watt USB port = super long charge time
10 Watt wall adapter = super quick charge time

 

[diabolic]

2.5 Watt USB port = super long charge time
10 Watt wall adapter = super quick charge time

It isn't that quick.

 

[shujin]

No it's not that quick but it is four times faster.

 

[tomneff]

The classic Mac USB port puts out 0.5 amps of 5V power per the original USB spec. Late model MacBooks like the Air can increase their power output if they sense a device (like the SuperDrive) that wants it. The ultracompact "cube" USB wall charger for iPhone 3G puts out 1.0A of 5V. The 10W power adapter sold for the iPad puts out 2.1A of 5.1V power. The result is that they all charge the iPad, but at different rates. For a fast charge at the airport, you will want to bring your 10W adapter. If you're mostly tetherable to wall or computer power in an office environment, you can use anything.

 

[/dev/toaster]

Has anyone tried chargine it using the iphone adapter ? Is it safe ?

 

[Consultant]

Has anyone tried chargine it using the iphone adapter ? Is it safe ?

I use my iPhone charger. Probably doesn't have as much power as the iPad wall charger.

 

[andyblila]

I use my iPhone charger. Probably doesn't have as much power as the iPad wall charger.

iPhone charger is 5W, and the iPad's is 10W.

 

[Chundles]

iPad 10W Power Adapter = 2.1A
USB 2.0 port = 500mA (some new Macs can ramp it up to 1A but none of them will output the full 2.1A that the wall charger does)

Hence, the wall charger will charge the iPad ~4x faster than a USB port AND it can be in use the whole time.

 

[danpass]

The classic Mac USB port puts out 0.5 amps of 5V power per the original USB spec. Late model MacBooks like the Air can increase their power output if they sense a device (like the SuperDrive) that wants it. The ultracompact "cube" USB wall charger for iPhone 3G puts out 1.0A of 5V. The 10W power adapter sold for the iPad puts out 2.1A of 5.1V power. The result is that they all charge the iPad, but at different rates. For a fast charge at the airport, you will want to bring your 10W adapter. If you're mostly tetherable to wall or computer power in an office environment, you can use anything.

Thanks.

Since I haven't seen otherwise …… the current iPhone USB cord can be used in the ipad for charging*? It'll sync as well?





*My car Belkin dual charger puts out 1A when only one device is plugged in and it accepts the iPhone cable (in addition to any other USB cable)

 

[hsotnicam8002]

I used my iPad yesterday until the battery was so low that it shut off. This is the first time I have done that in the 7 weeks I have had it. I have been getting excellent usage times (10+ hours) and previously have mainly charged it from a USB hub connected to my iMac whilst working on the computer. I haven't really noticed how long it takes to top up the charge, but it must be within 4 hours. The battery indicator always show 100% after that period of time.

Here is the issue. After it shut off, I plugged it in to my wall charger. After 2 hours there was still no charge indicated. I unplugged and tried to restart it, thinking that a reset might show there was actually some charge. But there was still no charge shown. In fact the iPad immediately shut down. I tried plugging into my USB hub, in case my wall charger was faulty. The same issue remained. There was an battery icon in the centre of the screen but nothing seems to have changed after another half hour. I reset the device several times then left it on the wall charger again. Now, after about 4 hours there is 55% battery life indicated.

Anyone know what's going on? 4 hours to charge to 55% seems very slow, especially on the wall charger. Has my iPad lost it's magic? Should I contact my local wizard?