The Sterling Power Alternator Protection Device (APD) is designed and intended to protect a 12V alternator from an alternator output/B+ terminal open circuit. We call this a "load dump". A load dump on the alternator circuit can be caused by turning a battery switch through the OFF position, or between bank 1/2/BOTH of the switch, if the switch wipes are worn. It only takes fractions of a second to blow the alternator diodes when alternator B+ gets open circuited.
With the growth of poorly designed, for a marine application, drop-in LiFePO4 batteries the Sterling Power Alternator Protection Device is really a critical piece of gear. These sealed internal BMS systems can open the battery circuit without any advanced warning. The Sterling Power Alternator Protection Device clamps or prevents damaging voltage transients that would otherwise blow the alternator diodes or damage equipment on the DC bus when the voltage transient occurs.
If your alternator is wired through a battery switch you can benefit from the Sterling Power Alternator Protection Device.
The Sterling Power Alternator Protection Device can also be used as a general DC system voltage transient suppressor. The Sterling Power Alternator Protection Device is far less costly than a vessel re-wire and is a great insurance policy that can be used to eliminate the risk of damaging voltage transients on-board your vessel.