That is correct but the problem is that some hot rodders are clueless about wiring. They'll add heavy current draws such as fans, CD ignitions, EFI, etc. on the battery side. Then they'll add a high amp alternator and plumb it into the stock wiring harness. The result is that now the bulkhead and ammeter have to deal with 30 or 40 amps continuous. The result is a meltdown and possibly a fire.