The voltages are acceptable, not ideal. 14.9v into a warm AGM could be too aggressive in some instances. The ECU's 13.7v choice is less of a concern with the AGM compared to the previous flooded battery, as while the screwy31 would only accept 6 to 12 amps when below 80% charged at 13.7v, the Northstar is now accepting 20 to 30 amps at this same voltage in the sub 80% range.
BFL, I am seriously questioning my Need for a T-1275 at all. Sure I do not have much reserve with just a 90AH rated AGM, but the other morning at 72AH from full, My engine started so easily, and 14 miles of driving combined with my Solar had the battery in the 99% range by mid afternoon, and that night the voltage it held under loading was still well above anything the screwy31 ever held. I am just so impressed with this AGM, and feel like relegating it to engine starting duty only, is a waste of its ability.
If I go the route of the small jumper battery for emergency start augmentation, well I think a battery like the Odyssey PC-925 would be ideal, But it is not much cheaper than a T-1275. 28AH vs 150AH for nearly the same price. BUt then again I know a 24$ UB12120 can also have enough CCA to assist the regular battery in such a situation as 14 years Ago i had no house battery and the jumper pack with a UB12120, 12Ah agm was always enough to get the v8 spinning..
My alternator is currently wired with the stock alternator 6gauge SAE circuit, In Addition to a parallel circuit, doubled 4 AWG jumper cable with clamps cut off directly from ALT(+) stud to my BlueSeas 6007m's common Stud with a 140 amp circuit breaker. I have additional 4 gauge Grounds from Alt(-) stud to nearby frame and directly to the load side of my Deltec500 amp shunt and from the Frame to the Shunt too. Not really much room for improvement via more copper.
I could in theory fit another alternator where my AC compressor currently resides. I removed everything else AC related years ago but the compressor which is now just a pulley. Even if a separately regulated alternator, I'd worry about it fighting the Mopar ECU VR with how my system is wired, and of course if I decide to not go with a dedicated house battery but instead walk the tightrope working the AGM like an evil overseer.
While I know I work my alternator hard, it only takes me 15 minutes to replace it, and It is a lifetime warranty unit. The last one replaced recently had to be ordered and delivered, but it was free, and gave warning that it was failing.
I think any alternator related improvements efforts would be a cold air intake feeding the back of the alternator where the air inlets are. No sense it trying to manipulate the ECM's VR if it is just waiting for a reason to take its ball and go home.
I need to thermal epoxy that DMM thermistor to the alternator case to see just how hot it gets.
