SOPine modules stay off at reboot?

[poVoq]

If you don't need the actual RTC backup functionality and you want to avoid applying hardware modifications to your Clusterboard, you could connect an external regulated 3.3 V DC power supply to the two pins of the battery holder, with a mandatory Schottky diode "inside" the "+" wire that connects the "+" of the external power supply to the "+" pin of the battery holder.  The purpose of the additional diode is to ensure that no current will flow from the PMICs on the SOPine modules into the external power supply, which would be really bad.

Even in this case, you'd need to solder two wires to the battery holder pins, or to somehow affix the wires reliably to the battery terminals inside the battery holder.

Thanks for the reply. I think I will try something like that.

But for my understanding: isn't the problem with the 2xAA batteries that the voltage drops when discharged and at some point it is lower than what it is connected to and thus the flow reverses? So if I have a stable 3.3V external power source, that should in theory never happen and thus a Schottkey diode wouldn't be needed?