I think these calorie readings are all a bit weird: I use cyclemeter on iphone (used mytracks on android because it gave me a speed plot over distance and altitude and average moving speed which was all I really need at the moment to see what I need to work on) and it tells me I used 1400 calories on a typical 35mile, 16.5 mph ride, which seems very large.
My tracks just plots gps it doesn't try to map the route and doesn't upload it unless you ask, so it's quite kind on the battery, cyclemeter seems the same.