'69 Charger... Charging issues. Battery and alternator test results.

[kaj750]

I searched this forum for half a day. Forgive me if I'm blind and missed a similar thread.
I'll try to keep this as short as possible:
When I let the car sit for a week or more the battery is completely dead. Like zero to where my portable charger not tender can read enough signal to turn on.
Posting screenshots and a video of my battery and alternator test.
I'm assuming the alternator is overcharging because of the way my electrical system works. I'm familiar that anything run off the battery causes the alternator to shoot more juice over to make up for it.
Is that the reason for my overcharging status?
Just want to be sure that neither of these parts are the reason for my battery dying.
Even worse, I feel there is a short somewhere in the car that is slowly draining power.
It's to the point where, even after jump starting the car (battery was FULLY drained) and driving it on the freeway for 30 minutes, the battery still didn't have enough juice to crank the car over.

Thoughts from some of you guys that know these cars are better than I?

Video:

 

[fine69]

I’m not one to diagnose something like this but I am curious, what is the ammeter doing while it’s running?

 

[dadsbee]

Dash clock? If so does it run? Aftermarket radio with live power feed?

Glove box or trunk light?

 

[PurpleBeeper]

Your battery is bad. It’s very typical to have a slow battery drain on 50 yr old wiring (+ clock)

 

[kaj750]

Your battery is bad. It’s very typical to have a slow battery drain on 50 yr old wiring (+ clock)

I’m not one to diagnose something like this but I am curious, what is the ammeter doing while it’s running?

Dash clock? If so does it run? Aftermarket radio with live power feed?

Glove box or trunk light?

No clock. OEM radio that lights up but not sure if it works otherwise. Ammeter is centered but occasionally moves 1/2-1 needles width towards the alternator side.

 

[R/T Boy 67]

Fully charge your battery, and then disconnect a battery cable. If it is dead after a week or so, then it is pooched. If it is still charged at 12.5 ish volts then you have a draw in your electrical system.

 

[Sixpactogo]

It is not your charging system. That is working fine. It don't take much of a draw to kill a battery in a couple days. I would charge it up good and put an amp meter in series with the battery plus cable and battery post to see how much of a draw you have. Even 5 milli amps will take a battery to zero in short order. If you have no current flow through your meter, your battery is junk. I had a .5A draw on my car once and it ended up being the glove box light was not shutting off.

 

[kaj750]

It is not your charging system. That is working fine. It don't take much of a draw to kill a battery in a couple days. I would charge it up good and put an amp meter in series with the battery plus cable and battery post to see how much of a draw you have. Even 5 milli amps will take a battery to zero in short order. If you have no current flow through your meter, your battery is junk. I had a .5A draw on my car once and it ended up being the glove box light was not shutting off.

I'll try tomorrow. Thank you

 

[kaj750]

Fully charge your battery, and then disconnect a battery cable. If it is dead after a week or so, then it is pooched. If it is still charged at 12.5 ish volts then you have a draw in your electrical system.

I used to DC the battery and it was fine. I was just concerned about the charging system since I had trouble after jump starting.

 

[Kern Dog]

My '70 has a light in the trunk. If I leave the trunk open for a day and a half, the battery drains down enough to prevent starting.
I also have a '75 Power Wagon with a 440. It charges and runs great but the battery in it does discharge when sitting. I've even swapped batteries with other cars and the problem persists so it isn't the battery itself for me. All it takes is about a week of inactivity so I've defaulted to just disconnecting the positive cable when it is not in use.
A guy on another forum thought that a diode in the alternator could be bad.
Now, I've made it clear to others here that electrical matters are my weakest link. I have no training and what I do know, I had to learn the hard way. It seems strange to me that an alternator could charge but still discharge with the engine at rest. A great forum member suggested that I disconnect the positive feed to the alternator and let the truck sit in the amount of time when it usually discharges. I intend to get to that and give it a try. The truck has nothing special to it....nothing but a cheap cassette player wired to have power only when the ignition is energized. No additional lights or fans, just a real basic setup.
I was told before that one test is to put a multi-meter on the battery and then have someone else pull one fuse at a time from the fuse panel and watch for a reaction. I don't recall specifics as to what you want to see, maybe a reading that was falling slightly suddenly stays even?
Cheers...

 

[Don Frelier]

It is not your charging system. That is working fine. It don't take much of a draw to kill a battery in a couple days. I would charge it up good and put an amp meter in series with the battery plus cable and battery post to see how much of a draw you have. Even 5 milli amps will take a battery to zero in short order. If you have no current flow through your meter, your battery is junk. I had a .5A draw on my car once and it ended up being the glove box light was not shutting off.

Maybe a typo.
5 milliamperes will not take a battery down very quickly.
.5 amps is 500 milliamperes.
There's quite a difference.

 

[twecomm]

You say no clock, stock radio. If your comment about the needle occasionally indicating slightly to discharge, and that's with car turned off, that's a clue that somethings wrong. With car off, should be no current draw on battery whatsoever, unless some accessory requires 12 V to keep alive. If you don't have one, get a
multimeter and use the current function of the meter as was suggested.
Disconnect + battery, set meter to measure DC current, put meter leads in series with the + battery lead and battery post. If you see any deflection or indication of current draw that would confirm that something is draining your battery. If yes, you need to dig deeper to find what's causing the discharge, if not... battery's likely bad.

 

[chescharger]

Bulkhead connection.