Thank you, the PDF in the linked post was very helpful.
So if I understand correctly, the charging circuit in the nRF52840 only supports Lithium batteries.
The bq2510x is a highly integrated family of single cell Li-Ion and Li-Pol chargers
This means, that I cannot charge Ni-MH batteries with it, but presumably I can still use them to power the board. Is there a way to disable the charging mechanism of the battery pins so that if I accidentally connect the board to USB-C, the battery is not charged?
The PDF also says “30-V Input Rating; with 6.5-V Input Overvoltage Protection”, so that would mean I should supply at most 6.5 V to it to not trigger the protection, right? Does that mean that the nRF52840 can also handle these 6.5 V?
And what is the minimum voltage I need to supply for the board to function? Is e.g., 3 V enough?
Sorry if these questions seem obvious, but I am pretty new to electronics overall and am still learning.
Thank you 