Monitor input voltage from USB on Electron?

Hi… using the USB port to charge the LIPO from a solar panel, I need to figure out how to monitor what level of power is coming in through the USB power, to determine whether the solar panel is capable of contuuing to charge the LiPO On board.

I’m familiar with FuelGauge - already using that to determine status of the LIPO system.

Anyone have a hint here ?

You can add a INA219 current voltage sensor to the mix to know exactly what the incoming voltage and current is.

You could use the INA3221 to measure 3 sources of voltage and current like the incoming USB power + incoming solar power. I just got the INA3221 library working on the Photon so that part is done.

Yes, but monitor it where ? Does VIN carry whatever comes in through the USB ?

You would have to monitor it externally.

I’m pretty sure there is no way to do it via code.

The PMIC chip does all this automatically. What exactly are you trying to accomplish?

building a device that will float down a river and record gps coords. need to figure out when i’m on battery alone and no input charge from the solar panel onboard, so that I can start doing things to conserve power…

The simpliest thing to do is to just conserve power when you hit a certain State of Charge like anywhere between 10-30% SOC.

Just figure out how much your SOC drops from sun down to sun up and then you know how much you should budget to make it though the night till the next morning when the sun comes back up.