A 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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  • tjolley - Sunday, November 3, 2013 - link

    You can if you have AT&T. I use my iPhone as a hotspot every week and also as a phone at the same time. No muss, no fuss. Verizon? Sprint? ...not so much
  • Chris_80 - Monday, November 4, 2013 - link

    How long would the iPhone 5s last as a personal hotspot? 4 hours?
    Have you tested this? That would be interesting, too.
  • hrrmph - Saturday, November 2, 2013 - link

    It's great to see that Apple is innovating with the product, but they dramatically limited its appeal by leaving Micro-SDXC slots off of it.

    I finally have some statistics on the #1 most wanted feature that users want in a mini-tablet:

    - SD card reader - 26% of users with 9042 votes

    - Phone functionality - 17% of users with 5912 votes

    The poll was posted by Asus. I doubt that the numbers would be much different for a full sized tablet.

    Those two features are very much under-represented in the market offerings that exist today for phones, tablets, convertibles, and notebooks.

    To Apple's credit they offer a 64GB option for internal storage, but they want $200 for the privilege of having it. Worse, this is essentially equivalent to a $40 Micro-SDXC storage card, so you are very much being overcharged. An extra $100 on top of that (for a total premium of $300) gets you a more reasonable, but very costly, 128GB.

    Add in no WiFi-AC and an under-developed camera, and all the goodness of this idea looks far less compelling.

    Probably the most impressive thing about this device is the very healthy selection of telephony bands and frequencies. I wish more manufacturers took the telephony radio side of things more seriously.
  • darwinosx - Saturday, November 2, 2013 - link

    So Asus, who make an el cheap tablet/phone that nobody buys..commissioned a poll saying more people should buy it and you find this relevant how?
    The fact is hardly anyone uses SD cards. They are slow, unreliable, use non-contiguous memory and the manufactures know very few people use them or care about them. That is why both Apple and Google don't support them. Also device weight and thinness are factors.
    No ac isn't a great thing especially for people like me who have an Ac router at home but the reality it's going to be quite awhile before you see AC routers in coffee shops etc and I'd rather use LTE anyway. Plus I care a lot more about ac on my laptop than on a tablet and the iPad Airs wi-fi is improved over the iPad 4.
    An underdeveloped camera...this one actually made me laugh...
    The idea that any of these make the device less compelling is ridiculous. Nobody cares about these things.
  • purerice - Saturday, November 2, 2013 - link

    Here I am a mac user calling out an Apple troll... Seriously, please.

    Whatever the validity of an Asus survey is, an Achilles Heal of the iPads is an inability to "officially" connect to any physical device other than a PC. If not SD cards, then at least USB HDs.

    Apple is pricing the iPads for what they can get away with which is the same myopic pricing strategy that led to market share collapse 20 years ago... What's worse is that there is no strategic benefit to Apple to charge so much for SSD upgrades. By the time you bump iPads to 128MB, you run into Macbook pricing and a $999 Macbook gives smaller margins than a $799 iPad. $200 more gives you 4x the RAM, a functional file system, Windows compatibility option (if you're into that), as well as Linux, better peripheral compatibility, and not to be left out, a much faster machine. So while the MBA is a much better customer value than the IPA, Apple makes less money on them and less App store revenue as well. Apple would be MUUUUCH better off lowering the 128gb price to at or below $699.
  • dokujaryu - Saturday, November 2, 2013 - link

    You can connect an iPad to a Wifi HDD, which probably is more power efficient than a cabled connection.

  • mark3785 - Monday, November 4, 2013 - link

    I have the Kensington MobileLite with a 128GB SD card which cost less than $120 total. Very nice device and can support connecting to three devices at the same time.
  • MarkWebb - Sunday, November 3, 2013 - link

    Bravo, my sentiments exactly, memory to the people! The cost for the steps up in storage are a real gouge ....
  • BillBear - Sunday, November 3, 2013 - link

    I have to agree. The prices Apple charges for Flash memory upgrades on iDevices have become indefensible. Especially charging one hundred dollars for an extra 16 Gigabytes of Flash that can't possibly cost them ten dollars in materials.

    It's well past time for 32 Gigs of Flash to be the baseline.
  • Impulses - Sunday, November 3, 2013 - link

    Asus makes cheap tablets that nobody buys? You mean like the Nexus 7 line? Where the card slot was only left out at Google's request since every other Asus tablet has one... SD cards aren't any slower or less reliable than internal storage, they're practically the same thing and work in much the same way (sadly, tablet/phone storage controllers haven't evolved much).

    The reasons to leave removable storage out are anything but technical... They're political and practical. The policy angle is obvious, pushing cloud services or enjoying high profit upsells on larger capacity SKU. The practical angle has more to due with the move away from file managers in mobile OS (because the general public never cared for the concept and just made a mess of file organization) and the way applications are written/loaded.

    I'm not saying that poll carries much stock, it was run by Asus to a very specific demographic I imagine... I do think it would be pretty inconsequential to include card slots in the iPad/Nexus line, design-wise anyway, it'd obviously hurt the OEM's bottom line since anyone with a need for 64GB+ of storage is smart enough to shop for a $30 card.

    At the same time, since I'm an Android user I actually think it matters very little as far as tablets are concerned. If I'm running out the door and wanna grab some movies or whatever I can just put them on a faster USB 3.0 stick and then access it later via USB OTG, or I can use Meenova's micro USB OTG / microSD reader.

    Removable storage on a phone where something dangling around is more precarious is a far bigger concern and yet everyone's following Apple's lead there too, blah. (except Samsung anyway, but that alone isn't enough for me to opt for their devices)

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