Proximity Sensor Battery Life Estimate

I take the old Proximity sensors (with the CR2477 battery, 1AH) and replace the battery with a CR2430 (300 mAh) to get a smaller form factor. I disable the beacon broadcasting, and turn on the telemetry broadcasting with a strength of 4db and an interval of 250 ms (although it appears to be 500ms when I look at the broadcasts).

The estimote app provides a battery life estimate of say 20 months. Can I multiply this by 1/3 to get my approximate battery life with the smaller battery?

I thought this made sense and I estimated 6 months, but I just had one drain in 47 days, and I’m worried. I don’t know if this was a bad battery or the actual battery life.

Any insight would help. Thanks!

PS. It would be awesome if the broadcast included the battery level, and didn’t require us to connect over BLE to get. In our application we can’t make the BLE connection.

Beacon provides information battery level in telemetry packets (see specs). You can find it in EstimoteTelemetryFull.batteryLevelPercentage in Android Proximity SDK.
However you used different battery type and those readouts might not be accurate since beacon thinks that it is still powered by bigger battery.
Battery level estimation was calibrated for battery type used in production where there is control over type, brand and manufacturing time. Battery that you used might have different parameters, different chemistry or might be stored (in not optimal conditions) for a long time before it was installed. So simply dividing estimated time by 3 might be inaccurate.

Any takers on this one?