Well, this topic is a bit old but I just finished putting together my "Mega Minnow Tank" and so far so good:
A 48 qt. cooler (already had it)
Marine Metal Super Saver aeration system...$42
Amp Outdoors 30 amp Lithium...$180
Electrical junction box (to hold battery, mounted on side of cooler)...$32
110v to 12v converter...$23
Seems like a lot but will get plenty of use...a couple of ice fishing trips with the fellas and numerous times to the Detroit River jigging Walleye. Thinking this thing should hold a few hundred minnows. Just dip what's needed for the day for individual containers. The battery will last between 12 and 15 hours and can be plugged in once we reach our destination (hotel, cabin, etc.) and the battery can be recharged off my Vexilar.