SFHLibertyCRD wrote:
A quick, and maybe basic, follow-up question:
Will the voltage reading vary depending on the charge state of the battery? Will my obd scanner show lower the voltage rate when the battery is full or near full because the generator is charging at a lower voltage like a "smart" battery charger does? I know it certainly goes down if there is a draw, but I read that the PCM has a controller for the charging system/voltage in the 2005. Does that explain why I'm getting a lower running voltage reading from my brand new battery than from my nearly dead one? From the manual:
The amount of DC current produced by the generator is controlled by the EVR (field control) circuitry contained within the PCM. This circuitry is connected
in series with the second rotor field terminal and ground. A battery temperature sensor, located in the battery tray housing, is used to sense battery temperature. This temperature data, along with data from monitored line voltage, is used by the PCM to vary the battery charging rate. This is done by cycling the ground path to control the strength of the rotor magnetic field. The PCM then compensates and regulates generator current output accordingly.
What you have quoted above definitely applies to the Gasser models ie. the
PCM adjusts the voltage in the alternator.
According to Keith from GDE the 2005/6 CRDs no longer have external regulation ie. the regulator is built into the alternator and has a "wake up" signal from the BCM I believe. This was discussed in depth in a previous post.....the documentation and circuit diagrams for the 2005/6 is very contradictory and does not give a description of how the CRD alternator works.....I do not have access to either of these two year model CRDs to test what is actually happening....my Export 2.5 2002 CRD definitely has the ECM regulate the alternators charging rate.
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