nRF52832 with LIS2DH accelerometer not powering up from battery

[Coz]

We created a custom made board with an nRF52832 and an LIS2DH accelerometer. The board is working fine when it is being powered from a power supply with 3V but when it is connected to a battery it does not power up. I found out that if I do not initialise the accelerometer (TWI driver) in the code then the board powers up fine with the battery. 

Both the accelerometer and the micro are being powered up directly from the battery with 3V. The board size is about 12mm in diameter (circular board).

I also found out that if a 47uF capacitor is placed after the battery output, close to the board, then it powers up just fine. The board is fitted with two 4.7uF ceramic capacitors which are required by the LIS2DH design. 

We do not have the space for a 47uF capacitor on the final design. 

Has anyone else come across a similar issue or knows how to fix it? Any help greatly appreciated.

[Turbo J]

Coz said:

The board size is about 12mm

Those batteries really don't like the operating current of an NRF52 due to thier high internal resistance.

You may want to look at the VCC voltage with an oscilloscope...

A few ideas to try:

Replacing the 4µ7 caps with the largest cap that fits in the footprint.

Delaying the initialization of LIS2DF and the TWI driver, using a low power (RTC based) timer, for a second or two after POR. This should raise the voltage of the battery that was drained during initialization of the NRF52 - but it also means you cannot simply use nrf_delay(), as this will keep the CPU running and current consumtion high.