I use duracell copper top,work well, but cost is high, batterys loose 50% at 0 degrees F. Why not get a .99 foram cooler at Kmart and add exrta insulation; paper,form or newspaper. I plan to go to rechargeables next winter as it gets cold in NS CA. Temps are up and down daily, but so far have captured lots of good stills and vids. I am using a Moultrie D 4.0