Iphone 3GI put my iPhone through its paces on the nearby Guadalupe River Trail yesterday, using pretty much every feature built into it. With iTunes running in the background, I walked for about two hours, snapped and uploaded 40 low-resolution pictures and sent three Twitter messages (walking while tweeting: not advised). When I walked in the door I got the “battery down to its last 20 percent” message.

Apple and other geeky types advise how to get the most mileage from the iPhone battery, which basically means you have to turn off all the cool gee-wiz features that inspired you to buy it to begin with. Such as:

  • Turn off 3G networking.
  • Turn off location features (the GPS capability).
  • Turn off “push” mail, which scans your e-mail account for new messages.
  • Don’t run iTunes in the background.

Thing is, as these devices get more and more like laptops, they have the same laptop-battery issues. It’s a mini-computer and drinks up battery power just like the big guys. Folks who need their laptops turned on for long stretches buy external battery packs (one of our photographers at the Merc has one duct-taped to his Apple Powerbook), and there are similar options for iPhone 3G users (though make sure yours is compatible with the 3G; the configuration’s a bit different from the first-gen iPhone).

Here’s a discussion of battery packs some people are using. A company called Morphie makes a cool charger/case combo but it won’t be in stores till the fall.

I suspect if you buy a car charger, though, the iPhone can come in very handy when bopping around town if your car doesn’t have one of those snazzy GPS units.

Incidentally, I did manage to get a signal from Sunol Wilderness from atop Flag Hill on Sunday. Made my very first cell phone call from the trail up there.

Previously: iPhone 3G: Any good in the outdoors?