I agree with farm hunter about deer preferring corn over oats, but I agree with you that they need more than just starches. We use bunk feeders to feed protien pellets and feed mixes.I guess it depends onwhere you're at, butthe problem with these is keeping the cattle and horses out of them. If you build oneof these, you get into building afence around it,etc. Pain in the neck, but worth it to get better nutrients to the deer population. About the batterystaying charged,I ALWAYS carry an extra charged battery with me. Sometimes the solar chargers can't keep up if you'refeeding a lot of corn each day. So I carry a backup. Good luck!