This is on my 68 Cutlass S 350 engine

Alt is cranking out over 14v
Battery is receiving over 13.5v under full load
No Parasitic draw. Only 0.02 amps (clock)

Battery charged and tested good. Week later it died again - starter click.

I replaced Autocraft Silver battery w 600CCA w Interstate Battery and 800CCA

Maybe one of these components are Drawing too much?:
Holley Sniper EFI
Electric fuel pump
Dual Electric Fan
Vintage Air system
Summit ProTorque Starter

After the battery died the first time, I thought the Alt wasn't cranking enough juice to run all of the electronics, so I got a 100amp Alt w internal regulator...but my batt died a little over a week later (yesterday) and that's when I bought the new batt.

Here's a clue: Before the batt died on both occasions, I noticed the headlights would blink for a brief second every 45 secs or so. After a full batt charge, this doesn't happen.

With the new Interstate Batt, everything is running fine...for now. We'll see what happens in a couple weeks.

If it's anything, I think it might be the Batt cables which have been replaced in the last 6 months. Don't know the gauge off the top of my head, but I think it's the standard cable.

Anyone have any ideas?

Thanks!

Rhett

 

You may have had a bad battery. Charge the old one up, let it sit not connected to anything and see if it discharges on its own.

 

How old was the Autocraft battery? Did it sit unused for long periods of time? Did you have it on a tender or smart charger? It might just have been worn out.

 

I had one that would go dead. found that my glove compartment light was on all the time. I put my car in dark garage then started to look around car and inside, and seen a light from glove box. Crazy

 

Do you know how to check current drain?

Start there and you will find that something is using current when the car is off.

 

Sticker on it said 9-17, so not too old. But it did sit around for about 6 months b/c of an issue with my former mechanic that deserves another thread...He installed The Autocraft batt too. When I drpped the car off to him, I had an AC Delco Batt in there.

I had it charged at oreilly after it died the first time. Their test said it was good for whatever that's worth.

 

That glove light has bitten me before too. I finally wised up though and made sure the door closed better and hit the plunger...before that I was lazy and just unscrewed the bulb.

 

When wet cell batteries sit unused and not charged for 6 months they can permanently lose capacity or even die (even if unconnected).

Be sure to put a charger on your wet cell battery when it is unused for an extended time or opt for an AGM battery which is more tolerant of being ignored.

 

You could have a bad regulator. I had one causing an intermittent draw. I didn't realize it until I had the car parked in the garage and I heard the radio start playing on its own. Good thing I left in on by accident.

 

Could be a intermittent draw, intermittent charging problem, voltage drop or something is drawing down when hot, you do have a few variables with the fuel pump, efi and fans. Start by checking voltage drop from battery to batt terminal on the alt, to starter and then ground side, batt to frame/body and engine block. Voltage drops should be less than 1/2 volt on either neg or pos

 

I got an AGM from Northstar last year. The guy who sold it to me told me it's fine to sit for long periods, but if I hook up a smart charger the thing should be just about indestructible, so that's what I've done. This is its first winter, so we'll see. So far, so good.

 

But that the problem with AGMs, they have to not get drained way way low. Had 2 powerful odyssey batteries die after being drained once or twice. Notice the constant charging and leaving them on maintenance charing stories for them in government use. Flooded batteries are better at long no charge times, but still need to be charged/driven daily. 5 years is about the life of a lead acid battery in normal use.

Got a topdon battery checker recently and it sure helps, but still finding out its limitations. I would recommend anyone using one to full charge their batteries first, or it might say replace when checked, but still some life left in one.