RAK19007 + RAK16002 – Battery monitoring with solar charging (RAK3312)

WisBlock
1

Hello RAKwireless team,

I am using the following WisBlock setup:

  • Core: RAK3312 (ESP32-S3 + SX1262)
  • Base Board: RAK19007 (2nd Gen)
  • Battery: PKCell 2500 mAh LiPo, currently connected to the RAK19007 battery connector
  • Solar panel: Connected to the RAK19007 solar connector
  • Firmware: .NET nanoFramework (C#), with BLE scanning, LoRa transmission and Deep Sleep every 15 minutes

Everything is working correctly, including solar charging.

I would like to monitor the battery voltage and preferably the state of charge (%) without soldering or modifying the PCB.

Since the RAK3312 does not appear to support ADC measurement of the RAK19007 battery voltage through AIN0, I am considering using the RAK16002 Coulomb Sensor (LTC2941) .

My proposed configuration is:

  1. Insert RAK16002 into the RAK19007 IO slot.
  2. Set J2 to pins 1–2 (internal charge/load).
  3. Set J4 to pins 1–2 (internal battery).
  4. Disconnect the LiPo battery from the RAK19007 battery connector and connect it to P1 on RAK16002 instead.
  5. Leave the RAK19007 battery connector empty.
  6. Keep the solar panel connected to the RAK19007 solar connector.
  7. Read battery information from the LTC2941 over I²C using .NET nanoFramework.

Could you please confirm the following?

  1. Will the RAK19007 correctly power the RAK3312 and charge the LiPo battery through the RAK16002 in this configuration?
  2. Will both solar charging current and battery discharge current pass through the LTC2941 sense resistor, allowing accurate coulomb counting?
  3. Are J2 = 1–2 and J4 = 1–2 the correct jumper settings for this setup?
  4. Is the P1 battery connector on RAK16002 compatible with the standard RAK19007 battery connector in terms of connector type and polarity?
  5. Is there a better RAKwireless WisBlock module or base board that supports battery monitoring without soldering or additional wiring?

My main requirement is to keep the RAK3312 and the existing .NET nanoFramework firmware.

I would appreciate confirmation based on the RAK19007 and RAK16002 schematics, or a tested example of this exact configuration.

Thank you!