H/O Alternator low voltage issues

[adjetta 10+ year member]

Okay so I purchased a mechman 270 amp alt for my 02 infiniti i35, I ran 0 gauge ofc from alt to battery positive, battery negative to strut tower, alt mount bracket to battery negative, and still cant find a good engine to frame ground...but my alt is not putting out impressive numbers. At first I had issues with belt slippage while under load even though i bought a belt that was 0.5" shorter, so I went down another half inch and it seems to be doing the trick but still at idle under load it bogs down to 12.5 if I run my heater, headlights, and heated rear window...I no longer hear it squeal, but I don't think it should drop this low regardless, so I wonder if the belt could still be too loose or if I have electrical connection issues, i'm afraid to drop it down further due to potential stress on the alt pulley bearings.

Its been charging at 14.4-14.5 typically, it will drop to 14.1-14.3 at idle after I start driving, and at lights 14.0-14.2, all of this is if its not under load...with load at idle its iffy, the blower motor and headlights usually doesnt effect it much, but if I turn on a heated seat or the rear defroster it drops down to 12.5

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[NASTY08IMPALA 5,000+ posts]

Okay so I purchased a mechman 270 amp alt for my 02 infiniti i35, I ran 0 gauge ofc from alt to battery positive, battery negative to strut tower, alt mount bracket to battery negative, and still cant find a good engine to frame ground...but my alt is not putting out impressive numbers. At first I had issues with belt slippage while under load even though i bought a belt that was 0.5" shorter, so I went down another half inch and it seems to be doing the trick but still at idle under load it bogs down to 12.5 if I run my heater, headlights, and heated rear window...I no longer hear it squeal, but I don't think it should drop this low regardless, so I wonder if the belt could still be too loose or if I have electrical connection issues, i'm afraid to drop it down further due to potential stress on the alt pulley bearings.
Its been charging at 14.4-14.5 typically, it will drop to 14.1-14.3 at idle after I start driving, and at lights 14.0-14.2, all of this is if its not under load...with load at idle its iffy, the blower motor and headlights usually doesnt effect it much, but if I turn on a heated seat or the rear defroster it drops down to 12.5

Thats the life of most ho alts bro unless u got a dc xp that does over 200 at idle ...the mechmans do like 140 .i kno i have one ....i drop to battery resting voltage after a while at idle nothing you can do ur drawing more than that thing produces at idle .now when im driving i never drop below 14.2..assuming ur talking about while the stereo is playing ..now if ur dropping that low without then yes you have issues

 

[adjetta 10+ year member]

Thats the life of most ho alts bro unless u got a dc xp that does over 200 at idle ...the mechmans do like 140 .i kno i have one ....i drop to battery resting voltage after a while at idle nothing you can do ur drawing more than that thing produces at idle .now when im driving i never drop below 14.2..assuming ur talking about while the stereo is playing ..now if ur dropping that low without then yes you have issues

well the drop is with a little 5 channel amp running, 250 watts rms on the sub, and 75 watts rms x 4 for the highs, but its not really the culprit for the low voltage

 

[NASTY08IMPALA 5,000+ posts]

well the drop is with a little 5 channel amp running, 250 watts rms on the sub, and 75 watts rms x 4 for the highs, but its not really the culprit for the low voltage

Dbl and triple check all the connections then call mechman and send it back ..3 months after i got mine that happened voltage dropped to 12 5 at idle and if i revved it up ot would hold steady at 15.1...it was a bad rectifier

 

[adjetta 10+ year member]

Dbl and triple check all the connections then call mechman and send it back ..3 months after i got mine that happened voltage dropped to 12 5 at idle and if i revved it up ot would hold steady at 15.1...it was a bad rectifier

hmm, idk I need to put a load in it to see how it holds up, on another note...your from Louisville, know of any good box builders?

 

[NASTY08IMPALA 5,000+ posts]

[quote name='adjetta']hmm, idk I need to put a load in it to see how it holds up, on another note...your from Louisville, know of any good box builders?[/QUOTE]

The guy that builds mine really doesnt do too many hes in etown ...but darren @dbeez; lives in crestwood he can hook u up
and if its not holding voltage at idle after u check connection no need to put it under load ..it has a problem