I'm concerned about getting the basic bike wiring going (As well as dealing with less safe limn batteries without understanding everything possible, i.e. they are far more prone to thermal runaway).
Per the link though, the batt bridge can be adjusted, probably a good idea for a smaller pack, you just choose different resistors to get the desired sensitivity:
" 40ma gives you high sensitivity (less than 1v difference to light an LED)."
http://www.evdl.org/pages/battbridge.html
Plenty of on the road experience:
https://www.google.com/#q=%22batt+br...r.com&safe=off
less than $1 in parts.