The state analysis from advertising and connection states can be used to investigate how the battery life varies depending on connection interval. For that purpose, a Power Calculator Tool [24] is provided that can be used to perform calculations for your custom application.

The calculations integrated into the spreadsheet are fairly simple. The average current draw during an event is calculated by the formula shown in Equation 1.

Equation 1.

For the connection event measured in Section 6.3.2, the average current during event is calculated with the formula shown in Equation 2.

Equation 2.

The next step is to calculate the average current for the entire connection interval, which takes into account the time during which the device is sleeping. For this, the formula in Equation 3 is used.

Equation 3.

For the connection event measured in Section 6.3.2, the average current while connected is calculated with the formula shown in Equation 4.

Equation 4.

The average current while connected is used to calculate the amount of time to expect that the battery last while running continuously in a connection. The total hours of battery life can be calculated using the simple formula shown in Equation 5.

Equation 5.

If you assume that the battery capacity is 230 mAh (a common capacity value for a CR2032 coin cell battery) and use the average current calculated from before, it is now possible to calculate the expected battery life with the formula shown in Equation 6.

Equation 6.

The battery can be expected to last for 23613 hours, or approximately 984 days, while running continuously in a connected state with a 1 second connection interval.

This is presented in the spreadsheet along with a similar calculation for when a device is in advertising mode. By modifying the interval settings, good estimations can be achieved for certain use cases.