I have the Zabera SP-30, 30 mile solar charger. It works, but I can hold the wire and it just kinda shocks you. I find it hard to believe a cow is deterred by it. I have however been using it for the last 3 months, and it does not appear than any of my cows or the bull have even dared to touch it. So I guess they respect it a bit. ( I only use it as cross fencing internally, or to keep them out of grass I am saving) I would NOT use it as the sole exterior fence.
I put another SP-30 on our heifer calves as of this weekend. They did not respect it when I had range cubes on the other side....went right through the two wire system I have been using. They all got shocked and jumped when I put the cubes out, but by the end of the day none had crossed back to the other side. Hopefully once is all it took. Ill find out Wednesday when I go check on them. I am hoping they respect it b/c if they don't they might get bred to early, and I dont want or need to deal with that. If they are mixed in Wednesday I will have to load the bull and move him, and I really dont want to do that.
One thing to think about. The larger gauge wire that you use the more current you can pass over a longer distance with less voltage loss. I electrified a 12.5 gauge high tensile alumnized steel cable for my top line, and then a cheap 17 gauge line for the bottom line. If I detach the bottom line, there is very little drop over the 1.2 miles I am charging on the top line. If I detach the top and charge the bottom, there is about a 25% drop on the 17gauge wire, and I have nothing touching the fence.