Wrestling with the wiring octopus - the EarthX install manual states "EarthX requires having automatic over-voltage protection (crowbar) for alternator type charging systems (not required for <20 Amp pad mount standby alternators). "  The Jabiru has an internal permanently excited single phase
AC generator with rectifier/regulator and the external regulator has an output voltage 14 volts + 0.8 volt, and may have a 20A fuse or circuit breaker between the regulator & battery.  The Viking forum has a discussion that seems to trend against the crowbar...  Crowbar for this combo????  Any recommendations/experience would be appreciated.

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Sounds like the Jabiru charging system is similar to the dynamo that is built into the Rotax 9 series engines. It is my understanding that EarthX does not require OV protection for such a system because the internal BMS (battery management system) can handle it. Larger alternators could overpower the internal BMS. But to be certain, why not contact EarthX? I have found them very responsive to inquiries.

Somewhere way back it was explained to me (don't remember who, but it wasn't EarthX) that since the Jab has a permanent magnet alternator, a "run away" alternator situation is impossible, so therefore, no crowbar protection is necessary.

This sounds reasonable, but I'm no electrician!  All I can say is that I've run my Jab 3300 with an EarthX battery for several hundred hours with no problems.  That's my story and I'm sticking to it! 

If EarthX tells you differently, please post their response!  



Earthx answered without delay - 

" We are going to update our technical information to reflect that your engine/charging system does not need the additional over voltage crowbar (along with the Rotax/ ULS Power permanent magnet charging systems).

 Tech Support,

P: (970) 674-8884

www.earthxbatteries.com "


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