There are a number of variables that go into the answer to this question:

  1. GPS signal strength
  2. Cellular signal strength
  3. type of cellular (2G, 3G, etc)
  4. make of batteries used
  5. temperature
  6. environmental factors (eg excessive bumps causing accelerometer wakeups)

We can provide some indicative numbers of the uploads that we get in accelerated upload testing:

Uploads @ 24 deg C
Uploads in Fridge
Uploads in Freezer
2G, Energizer Ultimate Lithium

Note that this does not include getting a GPS fix, so you should adjust these numbers down by approximately 15%.

And of course, nothing beats testing the devices in your real-world application.

We also recommend using fresh Engergizer Ultimate Lithium batteries, or other reputable 1.5V Lithium batteries.