The battery is less than two years old and displayed no issues prior to this. Installed on a 2003 Pontiac Grand Am.
The vehicle was completely dead after sitting for four days and read at 3.4 volts. I don’t have a slow charger so I just did a jump start. Alternator voltage checked out and after a 45 minute drive the battery read 12.6v.
So I checked for parasitic draw and it settled to about 100ma after 30 seconds (no alligator clips, so I’m not sure if it would settle further).
Could a 100ma draw do that in four days? After 24 hours the battery was down to 12.2v (disconnected from the vehicle), but I’m not sure if the battery is just now degraded from the full discharge/jump. Also, maybe I’m getting an inaccurate reading doing the parasitic draw test at 12.2v?
The only known issue is a currently bad blower motor resistor.
100mA is high for parasitic draw.
Pull fuses one by one to see where it’s going. If fuses don’t do it disconnect the alternator too.
45 minutes is not long enough to charge a flat battery. Takes at least 6 hours.
12.2V is too low. Not surprising after a 45 minute charge.
I suggest you get the battery fully charged and load tested, get something more definitive about the parasitic drain.
How regularly was the car driven before the 4 days it sat?
These days a lot of cars don’t get driven enough to keep the battery up.
Thanks. It’s driven a few times a week, but for short distances. The drive four days before it was found completely drained I took it on an hour long drive just because it had been a while, did some freeway driving. The battery read 12.2V 24 hours after the 45 min charge; it was at 12.6V 10 minutes after the charge and disconnected.
I’m going to pick up some alligator clips and replace the blower resistor tomorrow and see where it’s at. The battery is under warranty, but trying not to be a jerk and swap it for no good reason.
I agree that you should wait a while before checking the parasitic draw. On my current and past 2 Lincolns and my son’s Lincoln Aviator, the current draw was around 700 Milliamperes on all 4 vehicles. After waiting an hourish the draw would drop to around 75 MAs.
And yes a battery can go bad suddenly. The battery (3 year) I put in my Lincoln in January of 2019 was fine one day in February of 2020. The next day it was total junk. It would not even take a charge. After being on the charger/maintainer all night long it showed a bit over 1 volt with the charger disconnected and when the key was turned to RUN not even that.
A battery I bought for one of my motorcycles was brand new one day and total junk the next. I couldn’t beat a charge into it with a baseball bat.
With my '86 Taurus, everything–starter, accessories, lights, etc–operated normally but then a couple of hours later, there was not enough power to turn the starter. My local mechanic came over with his tools, found the 3 year old battery to be near-dead, and installed a new one in record time.
One of the failure modes of wet cell batteries is that two cells will short out to each other, resulting in immediate drop in voltage (aka failure).
As a battery goes through its charge-discharge cycles, material on the plates will flake and fall off. Over time, that material builds up in the empty space at the bottom of the battery. Once the buildup reaches a height where it touches two cells, those two cells will immediately short out.
I understand one of the things that more expensive batteries have is a taller empty space at the bottom under the plates. This helps to avoid the battery shorting out for a longer period of time.
I just surfed across the Google network for starter draw and found a world of opinions as always but it was interesting to note that DIYer types seemed to often recognize what I was taught 50+ years ago. Using a Chevrolet 350 engine as a baseline with a Sun VAT-28 or 45 a proper battery should be tested by throwing a momentary load of 550 amps then quickly dropping the load to 350 amps for 10 seconds. Then watch the actual amp draw and voltage drop while cranking the engine for 10 seconds with the ignition disabled. Normally the cranking test would result in an initial draw well past 400 amps followed by a continuous draw of ~350 amps with the voltage never dropping below 11.5.
And when considering amp draw to displacement it is necessary to consider individual cylinder displacement and compression ratio. But the initial high amp draw will often give the first indication of a battery nearing failure.
But maybe it takes a few decades of dealing with the basic fundamental equipment and methods to put all your faith in it. A good Vat 28 might be hard to beat in diagnosing charging and starting problems even today.
Another kind of driveway type of battery test is to charge the battery completely; if possible to 12.,6 or .7 volts. Remove the fuel pump fuse or relay and crank the engine for 10 to 15 seconds with a voltmeter connected. If the voltage drops below 10.2 or so the battery is weak. Dropping into the 8s or 9s means junk.
What irritates me about those inductance type testers is that I’ve had stores tell me their tester shows the battery is good when the battery is 100% garbage.
Just charge it the say. Well, it’s been on the charger for 6 hours before I brought it in…
Maybe your alternator is bad. Well no, the battery drops to 7 volts while it’s sitting on the bench…
Maybe your starter is bad. NO. What part of 7 volts on the bench is so hard to comprehend…
Maybe your car has a short. Jeez…
Been through this garbage 3 times with the last being Feb 2020. And each time they finally admitted the batteries were bad and replaced them. And I fully agree with Rod-Knox about the VAT machines.
So I did some more testing, the powered down draw sat at 120mA for about 20 minutes, then went down to 30mA and stayed there for another 10; I concluded parasitic draw wasn’t the issue. Battery voltage also dropped overnight to 12.1-12.2 again.
The battery was an Interstate from Costco, so they swapped it out for $2 (I guess the price went up, wasn’t going to argue $2 with a mask on). Some recent reviews online are saying that these are a junk brand now, but we’ll see.
Yeah, I still can’t explain the complete failure down to 3.4V. There is a bum remote starter installed that I no longer use (maybe I’ll find and pull the fuse out of that just to be safe). Probably the limited amount of driving/short trips over the past two years caused early degradation.