Esp32-c6 battery management

[Yostie]

Hi, I was just wondering if anyone had some good specs on the battery management used by the esp32-c6. I’m trying to work out if it includes over discharge protection. Also the documentation stats for input BAT is 4.2v. Does anyone know if the board will work with a slightly higher voltage of 4.35v provided by a HV LiPo.

Thanks in advance

[msfujino]

According to the schematic, the SGM40567-4.2 is used as the charge controller and can only charge up to 4.2V.
There is no over-discharge protection, so a battery with a protection circuit must be used if necessary.

[Yostie]

@msfujino thanks heaps for the quick reply. Appreciate the response. I’ll have to have a better look for the schematic this time.

[Toli]

I measured the charging and got different results:

Charging starts at 4.18 V and ends at 4.20 V charging Voltage. The Voltage will drop slightly below this Level (to 4.18 V) when disconnected after charging. If dis- and reconnected, charging will resume until 4.20 V is reached again.

(ESP32C6 USB on Macbook, Sketch Blink, Li-Ion Battery SLB-11A 1130 mAh)

Next experiment will be, how to calculate Battery status (% of full Battery). For that the measurement of the specific curve of voltage vs. drawn mAh is necessary. It is non-linear. Seeed has an example for measuring the voltage. Look for "seeedstudio, ESP32C6, measuring battery voltage“.

[msfujino]

@Toli

Charging starts at 4.18 V and ends at 4.20 V charging Voltage. The Voltage will drop slightly below this Level (to 4.18 V) when disconnected after charging. If dis- and reconnected, charging will resume until 4.20 V is reached again.

The voltage varies depending on the timing of the measurement. I recommend that you carefully read the following sections of the SGM40567 datasheet.

Figure 4. Charge Profile
Figure 5. Charge Profile
ELECTRICAL CHARACTERISTICS

Maximum Charging Voltage                 4.166   4.20  4.234  V
Output Voltage Fold-Back Holding         95.4    96    96.7   %
Full-Charge Voltage Detection Threshold  97      98.5   -     %

Not ESP32C6, but for your information.

Charging characteristics of XIAO_nRF52840 and XIAO_ESP32C3

XIAO_nRF52840 and XIAO_ESP32C3 have a built-in charging function, but since the circuit diagram was not disclosed, I assumed that they have the same circuit. I was curious and measured the charging characteristics. They are completely different, XIAO_nRF52840’s charging current can be set to 50mA or 100mA by firmware, but XIAO_ESP32C3’s is fixed and very large at 370mA, so I need to be very careful when using small capacity batteries. [XIAO_Charge]