Smartphones have utterly captured SXSW, and while there are certainly tablets and laptops to be seen, the outlets are ruled by smartphones. Glide along the walls and eventually you’ll trip over a charging smartphone. I’ve seen a few smart folks using USB or plug-in extended batteries or swapping out batteries, but it’s clear that folks need their smartphones and that the batteries aren’t lasting long enough.
Maybe these folks are early adopters of LTE networks, which can be tough on the battery, but conference environments are hard on phones. There are the multiple app downloads (I’ve been approached by Loku and asked to download its apps in exchange for a free taco, and I know other tempting offers are out there) and people are trying to tweet and check email in order to meet up with people. That’s a long time for the screen to be on, and screens are the largest consumer of power in a smartphone.
Plus conferences are crowded and the more people in a space, the louder each phone has to shout to be heard on the network. And that shouting takes power. So the more people, the harder the radio has to work and the more power it consumes. So if you want your phone to last one full day on a single charge at a place like SXSW, your best bet to use the same rules as when you travel overseas and try to conserve data: Put it in airplane mode and turn it on every hour. But then you can’t run apps like Highlight.