[patrickt]

With a fresh battery, it should settle down to close to zero pretty quickly after you start up, unless you really had to crank a lot. Maybe a minute or less of 20 amps is ok. You're not going to be able to spot leaking AC from the alternator unless you have an oscilloscope. But I wouldn't worry about that right now. And if your voltage stays under 14.7 volts, then I wouldn't touch the voltage regulator. Now, I will tell you that my Smiths ammeter, with the engine off, reports -60 amps when I turn on all my fans, and I know for a fact that they're only pulling 34 amps. But my amp gauge doesn't shake like yours. I think you probably just have an amp gauge that is getting a little flaky.