Battery not charging?

Good afternoon,

When did it read 15 volts?

Was the engine running when it read 12.36 volts?

Roy

Read 15 volts when I started it. checked the voltage from alternator then attached cable to battery and volts read 12.36 and wouldn't go much higher after I pressed on the throttle.

15 Volts? Did you run the engine with a battery cable disconnected?

Roy

I had the cable that connects to the alternator disconnected to see if was producing volts. Once it read 1.5 to 1.76 then it started to read 15 volts that's when I attached cable to battery.

Okay, thanks.

No, it will not charge if the cable is off. The alternator needs battery voltage to charge the magnets for it to work.

You removing it and installing it while running most likely failed the alternator.

Never ever do that. Voltage spikes are never good for the system.

Roy

Alternator still reads 15 volts but when I attached cable and start engine battery reads 12.36 volts. Can it be a ground problem?

No, it is not charging if it is reading 12.36 volts. That is the battery voltage.

Roy

Then why does the alternator read voltage before it is attached to battery but not charging it after it is attached?

That is an internal issue. Again, you should never remove and attach the cable with the engine running. You failed the regulator and the diode trio.

Roy

Okay, thanks. I replaced the alternator and it is all fixed.

You are welcome.

Always glad to help.

Roy