There's "rebuilt" and there's "remanufactured". Rebuilt means "We fixed what looked ready to break again" and "remanufactured" means "we stripped it down to the frame and then replaced anything and everything that didn't meet or exceed new factory spec."
So...if a vendor is using the correct term for the job they do, a remanufactured alternator (or starter) will always be way more expensive--but should also be way more reliable.
Balmar isn't made by trolls or wee folk, but they do treat and integrate and special order some ways differently from what a conventional automotive supplier will. For instance, a marine
alternator is supposed to be ignition protected, while an automotive alternator will cause gasoline or propane
, etc. fumes to explode from sparking. And there's a matter of rating and cooling
, automotive alternators are designed to run with lots of air flowing past them. Marine alternators usually use double fans to get back some of the lost
airflow, and then de-rate or change components to withstand the higher heat and higher continuous output.