Creative idea, Richard, but there's a (quite a) few caveats. And shame on MIT engineers for not catching this one :p But the sad fact is that all electric circuits require a complete path for what is known as "Continuity." For a fence charger, this means that you need to "Ground" it. All fence chargers *I've* ever seen have four connections: two for power in, one for the "hot" side of the fence and one for the Ground. As far as automotive electronics being somehow "isolated," consider the fact of the common "Negative Ground" schema of the modern automobile... where the negative terminal of the battery (and alternator, which is typically affixed to the engine) is attached directly to the vehicle. Now, electric fences are not continuously charged. It's not like if you get a couple inches from one and a small lightning bolt issues forth to zap the unsuspecting livestock. Rather, they emit a few thousand volt pulse every second or two. Let's see... Engine Control Computer, ABS Control, ECC, BCM... what a wonderful world of computers available to fry with kilovolt pulses surging against the *ground.* No offence, Richard, but as a farmer of many years, it's advisable to keep your animals restrained in ... IN the containment area rather than create exclusionary zones to keep them OUT of. They will always outsmart you; instead of one containment area, you will end up with 35 'exclusionary zones.' Best to all!