I tried to find information about it, and want to confirm that it is OK to connect the external Lipo battery to pins 1 and 30 on the "BUS expansion port"? And that the battery will be charged when connected to the external USB power?

If you look at the schematic you will see that pin30 on the bus and VBAT (on the lipo connector) are the same. So yes, you can replace the internal battery with an external one with the same voltage!

@skyflyer said in External 1S LIPO on M5Core2 BUS PIN1 and PIN30?:

And I don't need to remove the internal 500mAh battery, since they would be connected in parallel anyhow?

Do not simply put rechargeable batteries in parallel. Disconnect the internal one.

• You can have batteries in parallel but.. at a minimum you need some diodes to prevent them back-charging each other, have a look online where there is a lot of info about this.