Originally Posted by
Rob_E
From your description it sounds like the downside to your solution would be that it requires access to cell towers. I find that when I'm in rural areas, cell coverage can be a little spotty. In fact, if I notice that I'm getting poor coverage, or have reason to believe that I will, I've been known to power down my phone to save the battery power that gets wasted searching for a signal.
This is true, but you wouldn't need constant coverage for this to work. Even if you go through an area without coverage the logger will simply continue once it's back online. Of course, turning off your phone would disable the tracker.
Originally Posted by
Rob_E
My solution to map tracking has been to use my iPad to track my route, but I don't share it passively. In fact, I turn off any cellular data, wifi, and bluetooth to conserve battery and rely entirely on the GPS chip. This turns out to be pretty easy on the battery. It can sit in my pannier all day tracking my route (using MotionX GPS) and still have plenty of juice to spare at the end of the day.
Unfortunately, I don't think this can be replicated with an iPhone. I think the iPhone has only one setting with disables cellular and GPS at once (maybe I'm wrong about that, so someone should correct me). On my phone, the biggest battery drain when I'm not actively using it seems to come from trying to find a signal where there is none, so while your idea sounds great for good coverage areas, it seems like there'd need to be a way to fall back on GPS for those other times.
I think the same could be done with the iPhone since it's possible to disable data, wifi, and bluetooth. How accurate does MotionX record your track? Is it configurable?
Originally Posted by
Rob_E
And as for multi-function, route-tracking, cyclo-computer apps, I know that the location tracking is a battery drain, but in my experience, the biggest drain for any app is using the display. It might be worthwhile to do some battery tests using GPS tracking, but in a power-saving mode that keeps the screen off and maybe pings the GPS satellites at set intervals instead of constantly. It's hard to judge since the iPad battery is already longer lasting, but I find that GPS alone doesn't use that much power if all you want to do is save the location.
My thinking with this tracker is to enable and forget. The battery consumption would be close to nothing since it's relying on what the cell phone is doing anyway: tracking cell towers. As you mentioned before, the reliability of this tracker would depend on having cell phone coverage. However, it would give a rough track of the route traveled, which might suffice for the distances covered by bike touring (even if, say, you only had 1 or 2 updates per day). I wouldn't use it for hiking.
Thanks for your response!