I disconnected the battery while the engine was running to see if the alternator was charging. To my suprise, the volt guage INCREASED from around 12v to over 14v. Is that normal?

Yes. You would have problems if it hadn't.

12 volt reading was the battery itself, but once you disconnected the battery the alternator or generator kicks in between 12.78 to 13.25 volts to rev at 14.78 volts (+/-).

Any more than 15.3 to 16 volts with the engine revved, and you cook your battery.

I disconnected the battery while the engine was running to see if the alternator was charging. To my suprise, the volt guage INCREASED from around 12v to over 14v. Is that normal?

DON'T do that. It's murder on the alternator, and the spark may ignite the hydrogen/oxygen by the battery.

If the voltage increased then the battery was discharged, and drawing a current, or the alt is almost toast and can not keep up. A properly sized alt should be able to put out at least 13.5~14.5V at all times, with the battery hooked up or unhooked. If it is not, the alt is too small for the demand or on it's way out.

Steve

I disconnected the battery while the engine was running to see if the alternator was charging. To my suprise, the volt guage INCREASED from around 12v to over 14v. Is that normal?

When you removed the battery you removed the load that the alternator was charging. The battery pulls down the voltage. That's why when your battery is near dead and you change it the voltage will go up (less of a load to charge it when its new).

If the voltage increased then the battery was discharged, and drawing a current, or the alt is almost toast and can not keep up. A properly sized alt should be able to put out at least 13.5~14.5V at all times, with the battery hooked up or unhooked. If it is not, the alt is too small for the demand or on it's way out.

Steve
It is 2 battery system with a switch to isolate one batt from the other. Both batts are new and the alt was recently rebuilt. Maybe I should have the alt rechecked.