Not much difference on power use for the series connected versions. Line operated power supply to battery brings up more questions.
How long does display need to operate at a time?
Alk. or rechargeable? Go with re chg., flatter discharge V.
How bright do LED need to be, a small drop in current might not be noticeable.
My suggestion, use 8 AA's ' use 2N3904 as common emitter drivers [ emitters grounded ], or IC equivalent . @ 2600 mAh a drain of 320 mA about 8 hours.
For longer times try SLA 12V battery.
Ignore use of 74AC02, forgot about other 3 groups.
How long does display need to operate at a time?
Alk. or rechargeable? Go with re chg., flatter discharge V.
How bright do LED need to be, a small drop in current might not be noticeable.
My suggestion, use 8 AA's ' use 2N3904 as common emitter drivers [ emitters grounded ], or IC equivalent . @ 2600 mAh a drain of 320 mA about 8 hours.
For longer times try SLA 12V battery.
Ignore use of 74AC02, forgot about other 3 groups.