i bought a powermaster alternator for my 89' 305Tpi. I got the 140amp one from summit.

I've noticed that when it is cold outside(like in the morning) my gauge read about a little over 15volts. and when its warmed up, the alternator reads 14.2 volts. i have yet to put a DVM on it. but it does read higher in the cold than when it gets hot, is his normal.

 

Needs a new regulator. The voltage regulator should keep the voltage to within about a third of a volt of 14 VDC. More, it's shot, less, the alt is bad somehow. Voltage at the batt should be about 13.75 VDC (just a guess, not exactly sure what the exact number is).

Also, the battery puts out less amperage cold than hot. May be normal, may not be if the alt is putting out more juice cold than hot.

 

Perfectly normal operation, top target voltage for the regulator IC is 14.9 volts. Depending on battery condition, temp on cold start they usually read 14.5-15 volts for anywhere from 5 to 10 min. Day driving with light electrical load average voltage is around 13.5-14 volts. The regulator IC will also back down output as the rectifer pack gets hot. It's working fine.