Not fully charging batteries

[bwake]

While you are in the process of checking the alt and voltage drop to the batteries, check to see how much a/c voltage (a/c ripple) is making its way past the alt diode pack and to the batteries. I've recently run into several trucks that had cheap alts put on them and allowing too much a/c voltage to the batteries. This will not only take out the batteries in a quick fashion, it will cause all sorts of electrical gremlins to show up. Anything close to or over 100mV needs to have a new alt installed.