MoTeC Global Forum

Hello all,

Due to a configuration change on my engine I’m updating the alternator from a single wire to a more modern 2 wire and looking for some guidance on a Bosch 2 wire alternator control strategy.

Alternator in question is the Bosch AL0703N for a BMW M54B30 - description of factory function in attached photo.

I briefly started looking at the alternator control in M1 Tune, but thought I’d ask here as well.

Thank you!!

Hi,

I cannot find any information online that shows that these alternators are PWM controlled, which is who the M1 alternator control works.


If it is PWM controlled, you would need to find a setup running on the OEM ECU and capture the operating frequency and pulse width that the OEM ECU drives the control at. Without this information you run the rick of damaging the alternator and other components in the vehicle.

Hello,

Thank you for the response!

I did some more digging after my post and found that this version looks to still use the factory cluster and adds a switched 12v.

It would be nice to find a work around, but I guess the stock cluster is still an option.

Hi

Looking at the test procedure and the connector numbers, 15 & 61E, its looks like this is an
old type 9 diode self exciting alternator, once its rotating you can't stop it charging.
Although its rare to have a pin 15, you could try disconnecting the 3 pin whilst the engine
is running to see if the alternator stops charging, if it does then it might be possible to control via the M1

PM if you need help

Regards

Steve

GWR Motorsport