Charging Problems...Part II

[Elfer]

First of all, Id like to greet everyone a very merry christmas.
Now to my dilemma. Got the alternator rebuilt and is now showing 13.5+ volts when running. (prior to rebuild, it was about 12 v while running.) The dash light is not on, so far so good. I wanted to recharge the fully drained battery so I jump started the car and used the drained battery. Drove around for a while (at night) and came home. Battery is still drained and car wont start. While on a stop, I noticed that the headlights would glow brighter when I revved the engine and would dim at idle. The lights were not dim at all, they just got brighter when I revved it.
Would a fresh battery drain if I used it on my car? I know that when the volt meter reads over 12 volts, i.e. 13.5+ in my case, that the car is theoretically charging and is not just running on 12 volts from the battery. But why wouldnt it recharge the drained battery if its supposedly charging?
Any thoughts and suggestions would be greatly appreciated.
Thanks in advance.

[avendlerdp]

Your battery may be in need of replacement. It reads an ok voltage but can't deliver the amps to start the car. Check the connections on the starter as well. Alex

[pwd72s]

Alternator output...at what RPM? Should read around 14 volts at normal running speeds, I'd think.

[pjv911]

Sounds like a cooked battery. Also note that a bad battery could easily kill a perfect alternator by means of constantely absorbing maximum amps especially when revved. Sounds to me that you fixed the result and now must fix the cause(battery) Also 13.5 is a excellent volt reading at any rpm.

[RoninLB]

pjv911 sounds correct. A load test on battery will determine its condition. Don't forget what pjv911 said about a bad battery destroying a good alternator.

[Elfer]

I'd like to thank everyone for their input on the matter. I will install the new battery. I suppose that it shouldnt drain since 13.5 volts is in fact a good voltage. Maybe I was just a little paranoid after my experience with getting stranded at the mall after having completed the christmas shopping list. Thanks again everyone and have a happy new year!!!

Clint

[john walker's workshop]

you need to fully charge the battery before a load test is performed. a dead one will obviously test bad. do a cell gravity check with a hydrometer. they all should read in the center of the good section when fully charged. if one or more cells still read fair or low at this point, the battery should be replaced. load at 150A for 15 seconds and see if the battery stays at 10.5V or above while under load. if it drops down to 6 or 7V it's toast.

[pjv911]

John I always thought 9.6 volts was the cutoff for good or bad. But then again thats with a load of half the CCA for 15 sec. I suppose a load of only 150 CCA is not half. Please advise.