I use a 4 strand electric fence, with a Gallagher mini-strip grazer
charger. Uses 10 "D" cell batteries. They last about 10 weeks. Enough
time to revisit the yard several times. Cost about $100. With bacon
placed on the top wire, I've never had a bear go through the fence, even
if I erect the fence after the bear is actively working the yard.  Mike