My cows keep getting out and i have a solar powered 6volt fence charger. I have seen one that was hacked and it was very powerful. I would like to know how to do it. I could do it with one that plugs into an electrical outlet also. Any help appreciated.
Don't do it. What you're wanting to do is dangerous from a safety point of view, but also it would make you much more liable in the case of an accident. Instead, buy an electric fence that does want you want. Here's some articles that demonstrate what I'm talking about:
Now, you might be saying to yourself, "I wouldn't be as stupid as those people". But do you want to take that risk? At least if you buy a commercially made one then they have to go through all the safety testing and they assume some or most of the liability in case of a fatality. Just my opinion.
The AC powered ones are usually better. Also, check that you don't have weeds or tall grass touching the wire as that will reduce the voltage unless you have a current-controlled charger.
But before you do that, is your ground good? If you're in a dry desert-like climate, the ground is pretty poor and the cows are perhaps not being zapped hard enough, if at all. Even around here, when it's summer, the ground often dries out enough to provide a pretty weak charge.
We had a problem with a young colt getting out because he hadn't learned to respect the fence. What I ended up doing was stringing a ground wire a foot below the hot wire, so even on dry ground he would touch both and be hit hard enough to learn to stay away.
Just don't do what I did and absent-mindedly hold the hot wire in one hand while holding the ground in the other -- wakes you up in a hurry :-) That's a pretty good reason for not rolling your own right there: a buggy design could have killed me right there.