Notecarrier F 5 volts output on VBAT+

Hi all,

I noticed that the notecarrier F v1.3 outputs 5 volts to the VBAT+ when the system is powered via the microcontroller’s usb port (using feather v2). I believe that could be a problem, specially when recompilling code with a lipo battery connected to the notecarrier.


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Hi @theogrm,

Is your concern that you are using voltage-variable mode for your syncing cadence with Notehub, using two different power sources? If so, can you describe the scenario you’d like to address (i.e. USB power in development, but switch to LiPo mode when deploying?). For reference, there are many options that accommodate these scenarios: Low Power Design - Blues Developers but I’m happy to help figure out the right solution for you.


Hi Rob,

I just noted that with notecarrier-f v1.3 if power is fed via the microcontroller’s USB you get 5 volts at the VBAT where the LiPo are to be connected. If connected via the usb notecarrier, VBAT is the correct 4 volts.

Hi @theogrm,

Sorry about that - I misinterpreted your first message! It is by design of the Notecarrier F that it powers the Feather via VBAT with ~3.8-4V, with a diode to prevent any reverse current from flowing into its supply. It is also by design of any given Feather what they push out of VBAT when there is no VBAT present. Most Feathers have a battery charging circuit, so what is pushed out VBAT is more often than not the Feather’s attempt to charge its own LiPo. What you are observing is the interaction between those two things.