My car sits in the garage, doesnt get drove much but if you let it sit 3 weeks or so in a heated garage it hardly has enough power to start up also if you start it and drive it around then shut it off its hard to restart, gets scary sometimes wondering if it'll start. I did notice some small sparks coming off the backside of the alt., it looks like a little threaded rod with a small nut on it like 5/16th or smaller and a rubber grommet, this little rod assy. if you call it that sparks occasionally and I also noticed on the negative cable from the battery the small negative wire grouned to the inner fender was somewhat charred on the insulation. On the alt. the little rod I was describing doesnt have wires hooked to it. Once the car is running I throw 13 volts or a little over, nice and normal. Im guessing that maybe a new alt. would be in order even though this one is a new rebuilt, also a new negative cable with better and cleaner grounding connections, a new battery and maybe for good measure another ground strap from the engine to the frame with good clean metal to metal contact? Answers? Thanks fella's.

 

The 'threaded rod' is the alternators output back to the battery to charge it and supplimental power to the car while it's running. If it's sparking.. there's a problem there.
The chassis ground shouldn't be getting hot either (small or large negative cables). Make sure the neg. has a solid, clean ground to the block and the ground strap (rear of head to firewall) has good ties. Clean the mount point from batt. to chassis as well.

Don't beileve the gauge in the car... if ti were true.. my car would be consistantly charging at nearly 16v everytime I drive it (14.1-8v as read by a multimeter @ battery in reality)