High output alternator for Freightliner M2

You have a 28si series alt which only goes up to 200amps. To get 300 amps youl have to go to a 40si series like N15R-40P3001 or 8600298, but has a larger mounting pad.

 

Oh, by gar, this takes me back,,a "large car" alternator to light up all the chicken lights,,,

 

A picture would help, but a call to Delco customer service would probably be the easiest.

Call: 800.372.0222Technical Support Email: [email protected] Available: Mon thru Fri 8 AM - 5 PM ETCustomer Service Email: [email protected]: Mon thru Thur 7 AM - 6 PM ET, Fri 7 AM - 5 PM ET

 

It's just a voltage sense wire. This can be easily made to fit the 40SI if you terminate the wire with a ring terminal and install correctly.

 

They do make 200 amp 28SI alternators. But 28SI are brushed-type and IMO not the best. Yours is most likely a PAD-MOUNT style. So just make sure you keep that in mind.
The 40SI does come in a 300 amp version and is brushless. Also, these things are usually very rebuildable, i.e. the voltage regulator.

For your wiring question, look at the 28SI link below and the "FIGURE 5: TYPICAL WIRING DIAGRAM – 4 PIN PLUG" description. You should only have 1-wire on that connector as the "external sense" designation.

https://atelierdynamo.com/Pdf/Delco-28SI.pdf
https://www.delcoremy.com/documents...eets/installation-instructions-24si-28si.aspx

https://atelierdynamo.com/Pdf/Delco-40SI.pdf
https://www.delcoremy.com/documents...eets/installation-instructions-40si-55si.aspx