nPM1100 Charging Timeout with Low Charge Current – Workaround for Long Charge Duration

[Dzmitry]

Hi Nordic team,

we are using the nPM1100 PMIC together with an nRF52840 and are encountering limitations due to the charging timeout.

Issue description

Charging stops after approximately 7 hours (TOUTcharge), even though the battery is far from full.

System parameters

• Battery capacity: 4000 mAh

• Charge current: 100 mA

• PMIC: nPM1100

• MCU: nRF52840

Observed behavior

• Charging stops after ~7h

• NPM_ERR indicates timeout condition

• Battery voltage still well below full charge

Questions

1. Is there any way to extend or disable the TOUTcharge timeout?

2. Is it acceptable to periodically restart charging by resetting the PMIC with USB connected?
   Proposed workaround:

   • Detect timeout via ERR + CHG + VBAT

   • Enter ship mode via SHPHLD

   • Wake up via RTC → restart charging cycle

3. Are there any risks with repeating this process over long charging durations (e.g., 40+ hours)?

4. Is there a recommended approach for low-current charging scenarios with large batteries?

Goal

Enable reliable charging of a 4000 mAh battery at 100 mA without being limited by the 7h timeout.

Thanks for your support!

[Håkon Alseth]

Hi,

 

Is it acceptable to periodically restart charging by resetting the PMIC with USB connected?
Proposed workaround:

• Detect timeout via ERR + CHG + VBAT

As stated in the charger error condition section, the error conditions are only cleared upon VBUS disconnect/connect:

https://docs.nordicsemi.com/bundle/ps_npm1100/page/chapters/charger.html#ariaid-title8

Enter ship mode via SHPHLD

Unfortunately, shipmode cannot be entered while VBUS is connected:

https://docs.nordicsemi.com/bundle/ps_npm1100/page/product_overview.html#ariaid-title7

 

The way to restart charging is to disconnect and reconnect VBUS signal.

 

Kind regards,

Håkon