Out-of-the-box it appears that the battery in the Rapid IoT device lasts less than a day.
I did see that the LCD backlight can be turned off, but haven't tried it yet.
Backlight_SetLevel ( BLIGHT_LEVEL_OFF )
But need to be able to put into deep sleep until a particular trigger is detected (such as motion or interval timer).
I haven't found anything like that in the SDK docs.
It is true that the OOB (out of the box) application which is installed during manufacturing depletes the battery within about 2 hours (assuming 100% charge as a starting point)
This application is meant to demonstrate various capabilities of the kit, but is clearly not low power oriented.
There are several easy tricks you can play to adjust power consumption, heavily depending on what application you intend to design.
We are going to release an updated version of the OOB application to be downloaded via the studio with a couple of changes to make the battery last longer.
You can easily implement some yourself already today, by changing parameters of the elements in the Rapid IoT Studio:
- Backlight: You can either turn it off or decrease the intensity. This can save up to 15%
- CCS811: Air quality sensor. The default mode is mode 1 = 1 reading every second (consumes about 16mA continuously). Switching to mode 2 (1 reading every 10 sec.) saves 15mA (another 10 to 15%)
- Decrease the interval of sensors update. In OOB it is 1 second for most sensors.
Then depending on your final application need and programmming level you can:
- Decrease the K64 clock. By defaul it is set to 120MHz but could be set to 48MHz
- Turn all unused sensor of.
- Shut the KW41z off if BLE is not needed in your application
This all really dépends on the application you want to develop
The SDK uses NXP's FreeRTOS. In the FreeRTOS documentation you will find information about low power mode hooks.
FYI The graphical paging system is from Segger, emWin. You'll want to get that API too.
Also, please consider that you have two MCUs there a KW41Z and a K64F, each of them has their own peripherals and modules that might be impacting your battery performance.