improvised cluster battery holders?

[kage_no_mozaiku]

i took apart my flashlight today, one of the LED lights from china, and noticed the AAA batteries are held in a frame which puts them in a triangular cluster. now with, say a hasbro board, you dont want to go over 5V, and 3 AA are only 4.5V......how good of an idea is it to use this? i was thinking a good one since theyre packed in tighter which would be great for the cramped space in an MHS hilt. this is probably a separate question....but having them like this, could you use two of them in line and just install a pair of resistors so it wouldnt fry the board? im hoping it would cus im thinking it'd provide longer run time. god i hope this is easy to follow. ive been told my questions/comments are a bit confusing sometimes.

and yes i was thinking Li-Ion with a charger.