Here is a graph of the sensor data I collected with the sensor in the box.

The battery only lasted about 46 hours.  I would consider this the worst case for the battery usage since I was not doing anything to reduce consumption.  One simple thing to do is to use the Spark.sleep() instead of just delay() that I am using now.  This will put the core into sleep mode with low power consumption.  I am testing this now to see how much it helps.

The next big thing to do is to push the data instead of having the core serve the data.  This way the core can be sleeping and only wake up when a reading is needed.  This seem easy to do also using the Spark.publish() which generates an event that can be collected. There is a nice write up on on how to increase battery life https://learn.adafruit.com/low-power-wifi-datalogging/battery-life-and-current-consumption

I will post a follow-up once I get more data and do more tests.