iPad Air Delivers 24 Hours of Battery Life as LTE Hotspot
by Anand Lal Shimpi on November 2, 2013 1:15 AM ESTA year ago during my review of the LTE iPad 3 I decided to find out how long the iPad would last as a personal hotspot. With the display off and a single notebook tethered wirelessly to the iPad downloading at a constant 50KB/s, the LTE iPad 3 lasted 25.28 hours on a single charge.
The new iPad Air moves to a much smaller battery (32.4Wh vs. 42.5Wh), but at the same time it enjoys much lower platform power. The A7 SoC is built on Samsung's 28nm LP process, while the A5X used in the iPad 3 was a 45nm part. Qualcomm's MDM9600 in the iPad 3 was also built on a 45nm process, compared to the 28nm process used on the MDM9615M (the same modem used in the iPhone 5s). An improvement of two process nodes on both the SoC and modem should account for something.
I also crudely measured idle platform power as being substantially lower on the iPad Air compared to the iPad 4. All indications seem to point to the iPad Air being just as capable of an LTE hotspot with insane battery life as previous generation models. To find out I crafted a slightly updated version of the old test.
I set the iPad Air up as a personal hotspot, wirelessly tethering it to a 13-inch MacBook Pro with Retina Display. I started a constant 100KB/s transfer on the MacBook Pro (2x the transfer rate of my iPad 3 test) and with the iPad Air's display off I measured battery life. Last time I chose 50KB/s as it was the average transfer rate across our old WiFi web browsing battery life test, I doubled the workload to be more reflective of more strenuous demands. In reality I'd expect to see a burstier usage profile, but that's something for me to test down the road.
A total of 24.08 hours and over 8GB of transfers later, the iPad Air finally died. Just like last time, you'll likely burn through your monthly data allotment before you run out of power.
I've always been a fan of tablets with cellular connectivity as it is really improves the usability of the device. Tethering to a smartphone is always an option, but there's something to be said about the convenience of having a single device that is immediately connected. The ability to turn a tablet into an LTE hotspot with incredible battery life is just an added bonus.
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KoolAidMan1 - Saturday, November 2, 2013 - link
Are you for real? I got one yesterday and it is just as rigid as the 3, there are no problems with twisting or strength.Lord 666 - Saturday, November 2, 2013 - link
Place one hand on top and one on the bottom. Now twist and watch the screen flicker.darkcrayon - Monday, November 4, 2013 - link
Heh, well I can confirm it needs more force than I'm willing to apply to it to test your theory. It's like saying spiking your Note III into the ground may cause it to break.ciparis - Saturday, November 2, 2013 - link
"Hey doc, it hurts when I do this!""Then don't do that."
Lord 666 - Saturday, November 2, 2013 - link
Have you held an iPad Air even? Doubtful. Go to the store and you can see for yourself. Or Anand can confirm that the torsion rigidity is no where what it used to be.Better yet, send me $500 and I will video myself folding it in half while wearing gloves.
web2dot0 - Saturday, November 2, 2013 - link
So you buy the tablet so you can bend it? Ok. That's right. That's the first thing I do, .... try to bend the thing and see if it pass the "bend test".Why don't we focus on something more useful, like would it crack more often if it's dropped .... compared to the old iPads? .... You know, something more realistic.
BTW, send me $1000 and I can do the test for you and video tape it. ;-D Fool.
fourthletter - Saturday, November 2, 2013 - link
I would tend to use my phone as an access point, then connect a tablet to it.TrackSmart - Saturday, November 2, 2013 - link
While I don't like the idea of a monthly bill for an accessory computing device, the problem with wireless tethering is that you can drain a phone battery extremely quickly. And the phone is a more necessary device for me when on the road, than the tablet (for communication, GPS navigation, etc).Another option would be to tether via USB, but that's a hassle to setup and leaves you with clunky wired connection... Not ideal while on a crowded subway.
purerice - Saturday, November 2, 2013 - link
I must live in the dark ages but I could never get reception in the subway when I lived in a town with one... If battery life is your main problem, some emergency phone chargers claim they can help get you through another few hours of data use. I have one but have never had to use it.iSayuSay - Sunday, November 3, 2013 - link
Or how about pay extra $130 for iPad with Cellular and suck it instead of buying mobile charger? In fact turn it the other way around. Make the iPad as access point for your phone and as in this test, you'll get a mobile router with 24hours of battery life. Problem. Solved. :)