Re: 1995-150 Is 15.2 volts at WOT too high?
Hard one to say...
First...what is NORMAL? What have you observed over the years you have owned it? It is abnormally high NOW, or has it always been at 18v?
Plenty of guys see that kind of voltage every day. I don't think it should be any higher though...that is the upper limit in my opinion.....
The reason I say that, is that the battery plays a large role in "loading" the stator output.
That batt is an effective, huge current smoothing, almost self regulating producer of power. It has hundreds of times more raw electrical power behind it than does the stator. So, 18v at low current as it is supplied by the stator really does the battery no harm. It may boil off some water quickly, and over time it's internal chemistry may change, but overall it will not harm the batt.
Now, for the BUT....if the battery develops an internal resistance, some fault inside, then the application of an unregulated voltage will tend to cause the measured voltage to rise. In other words, the batt is no longer able to "absorb" or regulate down the voltage that is being applied. So, the stator and associated charging circuits "work harder" to maintain batt charge, they do it at a higher voltage and current, and eventually, the system fails. And it happens slowly over time, because generally it is due to battery age.
I am a big fan of making absolutely sure the battery is in good condition. Old, oxidized, sulfated batteries will kill the charging system over time.
If you are REALLY concerned about it, swap in a known good battery...a good fresh car battery...just to see if there is a difference. Or if it is old, just shotgun it and get a new one. Then WATCH it, and get your stake in the ground reference to help you in assessing whether you are developing problems.
