Hello all, first time writing,
was looking around in settings on my EMU Black to understand how to drive my Mazda NB Miata alternator, it’s an hi speed sort of pwm driver, switching 0-5v at 250hz varying DC to change charge target voltage. Do you have a clue how to do this or there is a reeady to go setting somewhere?
U can try it with a custom PWM output with an H-bridge. It outputs 12V but it is worth a try.
This is how I did it for the NBFL of a friend of mine, Hbridge connected to the alternator control wire
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Ok so i think there are two types of miata alterantor one is pwm and one is direct field control by frequency that one is no supported at the moment
As far as I know, there are 2 alternators. A self regulating, and an ecu regulated.
The self regulating doesn’t require anything on the ECU side to function.
The ECU regulated one I controlled as shown in the picture.
ive seen one with pwm but recently had one which was doing absolutely nothing on pwm ( tryied h bridge and aux) so and find out is frequecy controlled
Thanks, will try this!
Thanks for sharing
There are basically two types around (at least on NA and Nb/Nbfl models)
NAs (those with popup headlights) all use a standard self regulating alternator
NBs (those from 1998 to 2005) use an ecu regulated one.
I’ve always run the latter on a famous “do it yourself” ecu using the Miata specific protocol you posted, and always worked without a flaw. It’s a 250hz pwm modulated out 0-5v (made with a simple mosfet with 1kohm pullup to 5v).
Will try the proposed settings by Mikebau5 and will report (for those looking for a solution)
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I have a nearly stock 1.8vvt NBFL running with these settings without issue, so I would assume this would be correct. Let me know how it works for you! 
It works! Run the car for about an hour and voltage is really consistent! Thanks for sharing your settings.
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That’s great to hear! Enjoy