It seems that a low battery LED would be easiest to add, as the powerboost 1000c provides a breakout point for this (labelled as "LBO").
After a bit of research, it seems that additional LED(s) could be wired up to the ones already present on the powerboost: https://forums.adafruit.com/viewtopic.php?f=8&p=384809. In particular, I'm thinking of using a single RGB LED, such as http://uk.farnell.com/kingbright/l-154a ... dp/2290374 to indicate charging, fully charged and powered on statuses, and a second regular LED to indicate low battery.
My knowledge of electronics is not very good, but I am assuming that I would wire the 3 input pins on the RGB LED (corresponding to the 3 available colours), to the input/positive pads of the 3 LEDS on the powerboost, and the 4th pin on the RGB LED to ground. Assuming this is correct, I have the following questions:
- Would I need to remove the existing LEDs from the powerboost?
- Would I need to add any additional resistors to limit voltage through the extra LED?
- Would the extra LED's ground pin need to be wired to the ground pin on the powerboats, or would any other ground connection within the GBZ work?