@ctmorrison thanks for sharing!
if (!incoming_power() && battery_lower_than(LOW_BATT_CAPACITY)) {
System.sleep(SLEEP_MODE_DEEP, SLEEP_DURATION, SLEEP_DISABLE_WKP_PIN);
}
In your decision to SLEEP_DISABLE_WKP_PIN does this remove the ability to wake from deep sleep on a VUSB state change? This could be valuable to detect a restored power situation rather than waiting the entire sleep duration to get back online/charge battery. Here is a reference to the functionality I am referencing: Boron Solar Charging with 1.5.0-rc1 - #15 by Rftop