It appears that lines 16 and 18 in the example OnDemandDoubleLiIon have a small typo. On line 16, digitalWrite(13, HIGH) should be digitalWrite(3, HIGH). on line 18, digitalWrite(13, LOW) should be digitalWrite(3, LOW). Pin 3 is set as the activation pin earlier in the code.
On further study I realized I was incorrectly interpreting what the code was doing. Lines 16 and 18 are apparently just activating the built-in LED. The activation pin is activated by battery.voltage.
It appears that lines 16 and 18 in the example OnDemandDoubleLiIon have a small typo. On line 16, digitalWrite(13, HIGH) should be digitalWrite(3, HIGH). on line 18, digitalWrite(13, LOW) should be digitalWrite(3, LOW). Pin 3 is set as the activation pin earlier in the code.