diodes smoke test

[LKYusnret]

Altinator diodes need protection when the BMS shuts down the battery, how is this done? maybe an electronic relay signal from the BMS warrning high voltage disconnecting the power source ( ignation)) from the external regulator. My system using an Overkill 12V 120 AMP BMS, a Bulmat Alternator 604-120 , a external voltage regulator MC-614

 

[Hedges]

An alternator should always have battery connected, never get disconnected for the reason you mention.
Maybe you can make an electronic circuit to stop spikes, clamping to an elevated voltage above where alternator should deliver power so it doesn't have to burn watts.
Voltage regulator (inside or outside alternator) controls alternator output. Maybe easiest to mess with if external regulator and brush-type exciter.

Instead of BMS disconnecting on over-voltage, can you make it shut down alternator exciter?


"Ignition protected" suggests to me no brushes. Whether you can crowbar or interrupt regulator signal I don't know. You may have a way to tell regulator to shut down.

Balmar 604-120-DV Alternator -12 Volt 120 Amp Dual Pulley

 

[wholybee]

With a Balmar regulator and overkill solar BMS, the easiest option is to buy the Balmar alternator protection device which is made for this purpose. https://balmar.net/product/apm-12/

With some BMSs you can connect the BMS to a Wakespeed regulator which will safely shut down the alternator before disconnecting. But neither the overkill solar BMS or the Balmar regulators support that.

The first level of protection needs to be to properly setup all your charging so that a disconnect isn't something that would ever happen.