I'm thinking about getting an electric fence after 2 dog attacks, they have a run with a 4 foot fence and an extended run with 3 ft chicken wire. No surprise the dogs jumped it, the first time it happend I thought the owners would keep their dogs in but after the second time a week ago I'm done with trusting them. Now to the fence Energizer I'm looking for something under $50 or $60 that would charge 3-4 wires. I'm looking for something that I could keep outside with relatively low maintenance, If I have to charge it once a month that's fine. It only needs to charge 250ft of fence, I do have power in the coop and I can keep it inside If I need to. What would you recommend for how many joules it puts out and how many miles of fence. Thank you!