Electrical/Charging Issue - dead battery

[Super_Dave_D]

Experts – please help me diagnose my issue

Went to start my 88 3.2 up the other day and dead batter. Not completely dead but not enough to turn it over.

Noticed that my window switch was stuck in the up position. That lead me to the door switch that I determined was bad and left power to my windows.

I jumped it off and rode it around a bit and all seemed ok. No driving for 2 days and dead again. I jumped it again and all seems ok.

Now I have fixed the door switch and waiting on the window switch so I just make sure it’s not in the on position. Now I’m scared about the switch so I open the door and try the window to make sure the power is no longer supplied to the windows (I guess I’ll get over that in time).

I am concerned that I did some irreversible damage to my battery. Look at my numbers and tell me what you think.

Voltage at no start and no accessories – 12.15
Voltage (no start) with headlights on after one minute – 11.78

Voltage while running and no accessories @ 1500 RPM’s – 13.18
Voltage while running with AC, Radio and headlights on @ 1500 RPM’s – 12.45

Note: I have not actually taken my battery out and charged it. I guess this might be a good reason to procure one.

Thanks for your help!

[Early_S_Man]

Dave,

Anytime the battery won't start the car ... it needs to be recharged disconnected from the car! Trying to recharge a dead battery with your alternator is a risky strain on the alternator!

The battery has most certainly lost some capacity, but may not be ruined, yet!

Your alternator doesn't sound healthy with that 12.45 Volt reading! Further checks at 2500 rpm and 400 rpm would be justified after the battery is recharged overnight!

[bkreigsr]

super Dave, here's some useful info on charging numbers

Battery not charging