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BMS and you?re failure scenarios (Not an EarthX)

Postmortem: alternator internal voltage regulator failure

tl;dr

To answer which problem came first, the alternator or the battery? The alternator.

details:

I performed a bench test of the alternator (standard Vans model with internal voltage regulator installed 590 hours ago).

At the engine equivalent of 1000RPM, the alternator output voltage was 16.1V with a 2Amp load. With an old PC680 battery - with an initial no load voltage of 12.3V - added to the test circuit, the circuit voltage was 14.7 and starting to climb back up.

My conclusion is the Antigravity ATX20-RS BMS internal regulator - which is designed to handle short spikes - had worked much longer than it was designed and the battery internal temperature rose to the point the BMS eventually disengaged. Up until that point, the battery was taking enough load to keep my EMS voltage sensor below the 15V warning setting.

Once the battery disconnected, the remaining circuits were not a significant load, and the voltage started to rise.
 
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finding a ''crowbar'' that disconnects the alternator b lead from the system is not as easy as calling some vendors ,even though they advertise a product. they will discourage its use for this purpose.
perihelion [?] does have equipment made for exactly this application. i put one of their ovm's in that disconnects a 200 amp relay between the alternator and the main bus.
also, anyone thinking about checking their ovm should be aware that you may fry an alternator by disconnecting it from a heavy load.
 
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