[davepl]

Ah, that makes sense. In a normal setup (ie: every one I've done before) I've always included the idiot light. That voltage differential (sense line) must be important for some reason.

As for size, you need to scale it to what you're running. My truck really has no additional extra load beyond stock, but if you've got dual electric fans and a big electric fuel pump and extra lighting and so on, then it becomes an issue.

My Range Rover, for example, has a heated windshield, heated rear window, heated steering wheel, four heated seats, and on and on. That's why it has a monstrous alternator (sounds like close to 200A just adding that stuff up at 12V) that they literally liquid-cool. Only liquid-cooled alternator I've run across.