is that with the stock gauge or a multimeter?

either way if you are getting 15.2 with a multimeter check terminals and make sure they are clean(you can clean them with a wire brush and baking soda mixed with water), make sure everything is bolted up right(no loose cables)

dirty terminals can cause resistance and that can create an overcharge senario

if the battery terminals are spotless and connections are perfect check your alternator, take your multimeter and attach it to the alternator itself and checking the voltage coming out of the alternator, it should read 14.7 or somewhere around that area, if you are seeing more than your alternator is the problem and it needs to be replaced

EDIT if you can take a pic if battery before cleaning it if it needs to be cleaned

I'll work it AM, the only thing I have done is cleaned/degreased the engine last week. I'll reseat all the connectors. I did not get any in the battery area.

let me know how it goes

also did you happen to use water when cleaning the engine? if you did, did you get any around the alternator?

The footnote in the FSM says "*: Adjustment range of power generation voltage variable control is 11.4 - 15.6 V." I don't know that it can be adjusted but it sure sounds like it can.

15.1-15.3V running, if I disconnect the negative battery lead it jumps to 16V

That is less than .1 volts across 6 cells. It should be fine until I can get a replacement this weekend.

Can anyone verify that you get a brake lite with the battery lite? I need to know if this is normal!

Or do I have two problems.

Brake light is probably low fluid level in reservoir. 370Zs seem to be real picky about the level. Fill it to the top mark.

I don't think the two are related but can't swear to it.

Beg/borrow/steal an OBD scanner and the car should tell you what is wrong.

Fluid is full and, ZERO codes

all cells took 3-4 oz of water each. I think it was to late to save it. 3 years +

If you still have high voltage after replacing the battery, the FSM says to repair/replace the alternator. I found no procedure to adjust the settings in the ECM although the ECM does seem to have a lot of control over charging voltage (if I understood what I read). A Nissan dealer can do an in-depth test of the system using CONSULT but I saw no mention of any adjustments.

Copy the battery did not fix it, Alt is on order, 7 AM tomorrow Thanks for all the help

blown 10A fuse at battery fuse block. I hope carquest will take back the Alt in the morning. I am so happy!!!!!!!!!!

Which fuse?

Open the battery compartment, the small fuse block in front of the battery has a pull off top. There are two 10A fuses in the block. One is for the charging system the name of each fuse is cast/molded into the top of the cover.

Fuse #32 supplies battery voltage signal to the "S" terminal on the regulator. Apparently the charging system reverted to its equivalent of limp mode when it lost that signal.

How did you determine it was the fuse? Was there something that lead you in that direction or were you just checking all the fuses?