那我问问行家,下面的说法可信不?
问:I've heard a story that a weak vehicle battery can destroy an alternator or cause an alternator to fail early.
Is this true, or is it largely fiction?
答:Absolutely yes. I sell alternators all day every day - and a poor battery is often the root cause of alternator failure.
A battery with a short in it will cause the alternator to run at full output for extended periods of time, if not continuously - and they are not built to do this. Alternators the world over are built to supply an initial high current, tapering back as the current used to start the vehicle is replenished. Constant running at full output simply overheats them and the rectifiers fail. *See edit below
If your battery is 'Open Circuit' the alternator will either not start charging at all or will erratically bounce from low to high voltage. This causes the regulator to fail prematurely (or immediately!)
A battery that simply will not accept charge won't necessarily cause premature failure of the alternator unless it is permanently at a low voltage, in which case see the 'shorted' section above.
Hope that helps?
*EDIT: Some bigger commercial and marine alternators are designed to run at full output constantly, but I don't get the feeling you're talking about those

In 16 years of selling parts for alternators I've never heard of the brushes and slipring wearing and the grease in the bearings overheating from high charge current at idle. These issues are caused by other problems not in scope of this question