EME's description of the original Bosch charging system versus their permanent magnet system is very clear.
"The original BOSCH alternator system used on Moto Guzzi’s from 1973-1995 was designed in the late 1960’s. The system is
based on energizing the rotor with electricity from the diode board,through the generator light and voltage regulator. Once the rotor is
electrically charged and spins inside the wire windings of the stator AC current is generated and sent to the Diode board, or “Rectifier”
to rectify or correct the AC current to DC current so it can be used to charge the battery. The Rectifier uses Diodes which are
like electrical gate keepers, to change the electricity from AC to DC.
The EnDuraLast EDL4MG Alternator Kit is a significant upgrade to the original charging system. The major components are manufactured
in Italy and the custom modifications done in the USA to the highest standards under ISO certifications.
It’s beauty is in its simplicity. No longer is the complex wiring from the diode board, generator light, voltage regulator and brushes
needed to energize the rotor because now the rotor is permanently magnetized. The brushless, permanent magnet rotor spins
inside the stator and AC current is generated in the stator wire windings. The stator is very robust. Failures are rare, caused by
excessive heat or physical impact damage.
The Regulator / Rectifier (R/R) then converts the AC current to DC current to charge the battery sending it via the RED wire. The
BLACK wire on the R/R is the voltage sensing wire. The voltage supplied here from your bikes battery tells the R/R what to do.
Once the battery no longer needs voltage it shunts the surplus to ground. It is a shunting style R/R. It is therefor extremely important
the R/R has a solid connection from it’s case to vehicle ground.
This alternator system can be envisioned as a stand alone system that will interact electrically with your bike at two points. It reads
the battery voltage via the BLACK wire, and depending on the information provided to it, will deliver available voltage via the RED
wire to the battery. All other electrical systems on your motorcycle including ignition are not impacted by this upgrade."