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Whacko battery[s]

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NutmegCT

NutmegCT

Great Pumpkin
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No, not the brand of battery. The characteristic of the battery!

Last October I tried starting my Altima. Nothing at all. No click, and just a flickering from all the warning lights.

Checked battery voltage - 10.2 volts with voltmeter. Used my jump start battery pack and got the car started fine.

Had no prior problems with battery.

Drove to Advance Auto (which sold the battery). Tech guy saw a crack in the case, so replaced the battery at no charge. Same type battery - Autocraft Gold. Battery date: 10/16.

AA checked the charging system - showed me the results. All checked out fine.

Two months later, exact thing happened on the *new* battery. This time, voltage had dropped to 9.8 volts, measured at the battery itself.

Jump started, returned to AA, and of course the battery now read 12.8v. Charging system tested fine.

Today, after two months of no problems, same thing. Voltage at the battery reads 8.2.

Is this another flakey battery? Or a case of "parasitic drain"?

What say ye all?

Thanks.
Tom M.
 
Okay...modern vehicles with computers, radio memory, remote doors and alarms....use power all the time.
Bottom line:

Modern vehicles with all the bells and whistles use power.

Reading your dissertation, it is difficult to fully grasp the scope of time involved. Do you drive this often, or twice a year?

Something is loading down periodically.
My guess would be glove box light, boot lamp, alarm, or one of a dozen or more electronic modules.

Pull the glove box bulb, under bonnet bulb, and boot lamp bulb, and see how it does over the same time frame where you have had failures.

Factory alarm/remote, or aftermarket?
 
a-HA! Just did a parasitic drain test.

https://www.wikihow.com/Find-a-Parasitic-Battery-Drain

200 mA drain is constant. Should be more like 20-40 mA.

Rest of the afternoon will be pulling fuses one at a time, determining which circuit is the culprit. Once circuit is identified, have to see what system on that circuit is lusting for power.

Have to say, it's puzzling that a drain could drop voltage from 13v yesterday evening, to 8v by the morning; you'd think it would happen more than once every few months.

Stay tuned ...
 
It seems from you description that it is intermittent. Hence the suggestion on the three bulbs since anything can happen to create that type of issue.

Just make sure when doing a drain test with the bonnet open you keep the doors closed and disable the under bonnet lamp.
 
Thanks Dave. All doors closed and there's no under-bonnet lamp.

Just finished removing all the fuses (engine bay and under dash). Only one removal actually changed the constant 0.20 amp draw - something called "Meter". And that only reduced draw from 0.19 to 0.12. Still way over the 0.02 it should be.

Question for you. If ammeter is set to the 20 amp scale, and reads 0.20 on the circuit - what is that reading in milliamps? I'm thinking 200 mA.

Draw *should* be from 20 to 40 mA on the car.
 
Right, 200 ma.
And while that is a problem, it's not enough to kill the battery overnight. Something else is going on.

Just as possible examples my Audi 100LS had a very similar problem. Only happened once or twice a month, but when it did, the battery would be dead in 12 hours. I finally found that one by chance : walked by the car one night and saw a light on the dash. Turned out the relay for the rear window defogger would self-activate when wet with dew!

More recently, my Buick started killing the battery only sometimes, after sitting for 4-5 days. That one was my fault in a way, the horn button had become intermittent and I dealt with the problem by disconnecting the horns. (In my defense, I was asleep when the neighbor rang the bell to complain about the noise.) What I didn't think about was the horn relay drawing enough to kill the battery over several days.

On the motorhome, it was a bunch of mud caked up on a terminal. The mud evidently had enough salt in it to conduct only when damp.
 
Randall - great insight. I remember that "every once and a while", the "alarm" light on the dash would be flashing if I walked past the car at night.

I just figured it means the alarm system was working. As there were no lights on, I wonder if the alarm is buggered up. Setting or disabling the alarm using the manual's instructions doesn't change the flashing - but the flashing seems to occur randomly.

Off to do more checking. It's been unusually humid here for the last couple of days too.

oy
 
Maybe I'll just start using a battery tender. yeesh

Now I realize the security system is working correctly. There's no "alarm"; it just locks the ignition system unless the key fob is near.

One by one I removed the fuses (under dash and under hood). No change in current draw except by removing the fuse "Meter", but that only drops the draw from .19 to .12 amp.

I charged the battery overnight, and found the drain dropped to .14A. Makes sense, as there's less voltage to "draw" on, so the draw would increase. So removing that Meter fuse now reduces drain from .14 to .12. But officially, I don't know what "normal" draw is supposed to be. Battery voltage now reads 12.4.

Shooting in the dark seems like a good analogy here.
 
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