Battery and/or Alternator problem diagnosis

Just looking for a bit of help here. When I go out to start my car it fires right up when cold, but when I take it for a short spin and kill it, it won't start right back up right away. Then, I let it sit overnight and then it started right up. Then the same thing happens again.

Also, I took it out for a longer spin the other day after starting it from cold and after about 10-15 minutes the stereo started losing power and the lights were dim when idling.

I recently put in a new belt for the alternator etc. and it seems to be very tight.

Any idea here? I will yank the battery and have it tested.

Any help is as always appreciated.

Year, engine, mileage?

When you say it won't start, do you mean it won't crank over?

Sounds like the alternator is not charging(is the RED battery light/symbol on?).....car runs until battery drops below 9.6 volts(when voltage drops below this, the car's computer can't function)..........then can't crank vehicle(battery too weak).....overnight, the battery recovers....

Battery should measure 12.6 volts with nothing on......with vehicle running, should measure 13.0-14.5 volts(high end on cold engine, low end on warm engine)....if you rev the engine to 2000 rpm, should see voltage increase....

Year, engine, mileage?

When you say it won't start, do you mean it won't crank over?

Sounds like the alternator is not charging(is the RED battery light/symbol on?).....car runs until battery drops below 9.6 volts(when voltage drops below this, the car's computer can't function)..........then can't crank vehicle(battery too weak).....overnight, the battery recovers....

Battery should measure 12.6 volts with nothing on......with vehicle running, should measure 13.0-14.5 volts(high end on cold engine, low end on warm engine)....if you rev the engine to 2000 rpm, should see voltage increase....

Oh:

'96 Z24, 2.4L. Mileage is at 125K right now. Had it for about 7 years now (since 85K) and only had to replace one "major" thing - the starter. I did that close to a year ago now. The battery is newer - around a year (or a little over) old.

It doesn't crank or cranks really slow until it starts making a clicking sound and then doesn't crank at all. Let it sit and then the next day a couple days in a row it started up. Then the process repeated.

If your battery load tests ok, then suspect bad battery cables..

Will it start if you jump start it?

Having the same problem as my OP now again. Anyone?

Having the same problem as my OP now again. Anyone?
Check for corroded connections on the battery cables.