im building the minty boost circuit version 3 here:
http://www.ladyada.net/make/mintyboost/parts.html

if you scroll down to the bottom of the page to the version 1 schematic, it has a low battery led. this is composed of LED1, R1,R2, and R3.

id like to add this feature to the version 3 schematic. can i simply add this? will the rest of the circuit operate the way it should?

edit:crap, i just noticed that version 3 and version 1 are 2 different ICs. wondering if this feature is even possible with version 3 IC?

 

The LT1302-5 used in version 2.0 and 3.0 does not have the LBI and LBO function pins.

It COULD be added, but you would need to add a comparator IC, a voltage reference, a couple of resistors to divide the battery voltage, an LED and a current limiting resistor for the LED. It wouldn't fit on the same board.