Try a refrigerator, even if it isn't plugged in, it should work better than an ice chest. Primers in the freezer section, powder in the other part.
If you can plug it in that's even better. You'll have to play with the settings and determine the best temperature, but since you probably won't need to keep either section as cold as possible, that should reduce the amount of electricity the refrigerator uses.
And you can sell it that the wife gets a new refrigerator and you can use the old one for powder & primers.