-
Earthloop used http://greenalp.com/RealTimeTracker/ on an android phone on the spiral ride with no complaints.
Yes, but that phone had an extra-large battery. I'm still using the greenalp tracker, and I have it set on the most battery-hungry mode (frequent updates) and it uses about 25% of battery per hour on my fairly typical phone. You can set it to be much more conservative.
Last time I looked there was no iphone version though
Extra battery essential just in case. But gps shouldn't be too heavy on battery.
Earthloop used
http://www.greenalp.com/RealTimeTracker/
On an android phone on the spiral ride with no complaints.