Dying battery

[crazyvwvanman]

A constant draw of only 90mA isn't going to drain the stock battery in 2 days.
That should take more like 3 weeks if battery is good.
Maybe the problem draw is gone for now?

Mark

[DanHoug]

[DuncanS]

aAbad cell will deplete a battery with no "phantom" draw.

[Ronzo_volvo_guy]

Duncan;

Please explain for a shorted failed cell, and open failed cell, how this can "deplete" a battery when the other term I know for deplete is discharge.

Cheers

[DuncanS]

All the individual cells in a single battery are in series. Imagine a series of pails connected together with hose at the bottom going from one pail to the next. Then there is another hose to take the water out. Unfortunately one cell has a leak, so the other pails try to fill it. So even if you have 5 pails which are OK, the sixth bad one sucks down the good ones. The cell can go bad for a number of reasons, but this explanations is good enough to explain the situation. The leak doesn't have to be at the bottom of the pail. Maybe it's half way down, so instead of the pails/battery full, it goes to half full at maybe 12.3 volts. This doesn't really answer your question, but whatever went wrong inside means the battery is toast. A shorted cell means that instead of the 6 cells producing 12.2 volts adding up to 12.68 after losses, it can now only produce 10.5. And the short causes heat which further degrades the good remaining cells. An open faiedl cell would mean no electricity can pass through it so the battery would read 0 voltage. A leak where the electrolyte drains out would produce that result. The net result is a depleted battery what every the cause. Like my bank account.

When I was a kid, batteries had individual cells which could be replaced. If one went bad the battery guy would cut the exposed lead connector straps on the top and put in a new cell. He had a mold and would cast a new connector between it and the original cells. Some are still made that way.

I don't pretend to know much about the chemistry and physics inside, but this is a rough explanation and is about all I think I know. It's about all I need to know to have to pony up and spring for a new one. Batteries, don't like heat nor repeated deep discharges.

Hope this helps some.

Duncan

[djkeev]

I was taught about batteries that each cell was tasked with working with the other cells as a team.

If one cell fell weak, the others would deplete themselves trying to bring the weak cell up to their level of health.

This applied to car batteries or ant multi small battery device such as a long flashlight.

Do not mix good and bad D, C, AA, AAA cells in a device. . In short order the bad cell will take down the entire lot!

Dave
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[Ronzo_volvo_guy]

Guys;

I don't disagree with what both of you say...ALL 6 cells must work right and contribute, both in chemical storage of the electricity, and in the ability to give back the charge as electricity, and with low impedance, else the Batt is useless ballast and due for lead recycling...what I am disagreeing with is the term "deplete" which has specific meaning when used with Batts.

Cheers

[jimf909]

[Ronzo_volvo_guy]

Jim;

I understand "deplete", when used with lead acid Batts, refers to the available active surface area of the lead plates...once it becomes sulfated, that surface is no longer available to do the necessary chemical things with the acid....the Batt is slowly "depleted" of this surface area over the course of its service life and chg/dischg cycles. Storage capacity goes continuously down, and Internal resistance goes continuously up, until sky high...then you can charge it to your hearts content, presuming all cells are in similar shape, the open circuit voltage will look OK at around 12.6V, but when applying any kind of load, the internal impedance is so high, that V just collapses like a stone...the Batt is then depleted and useless!...recycle time! A hydrometer test would give clues and show this also. I'll see if I can find a reference in Interstate Batt, or Batt University...

Individual cell failure can also certainly happen, causing other issues, but depletion occurs on all cells at the same rate during the Batt's service life.

Cheers

[Abscate]

Its pedantic unless you are really getting into battery specifics

Depleted, expired, dead, discharged are all common ways to describe a battery that can be recharged, but wont start a car in their current state.
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[AZ Landshaper]

After much testing and connecting and disconnecting I came to the conclusion that the battery was charging and holding if even at 12.3v resting. I connected the radio again and began to live the normal routine. Car starting every morning on the way to work. No real issue.

And then we throw a teenager into the picture.

Dad goes into pickup the pizza while teenager waits in the car. Being the typical teen she couldnt just hang tight and snapchat away. She had to have tunes to snap to. She turns the key and rocks out while Im inside.

We all know how this goes. She and I walk the short two miles home while eating the pizza and joking about life. Van failed to start...battery holding at 11.7v.
While it did afford me some quality time with my youngest offspring, Ill be buying a new battery today so my other daughter can begin using the van to commute to highschool. Hopefully this is the end of the story re the battery. And as stated above. Resting voltage should be above 12.4 or your running the same risk.
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[jimf909]

Okay, using these definitions:
- a brand new battery measuring 12.2 volts may be 50% discharged while only being 2% depleted and after a good charge will go on to start cars for many years if taken care of.
- a six year old battery measuring 12.6 volts is about 10% discharged but may be 70% depleted and may never start a car again.
- a bad cell is measured with a hydrometer to show specific gravity in each cell
- I believe the only practical way of measuring depletion is through a load test

Now, on to the problem at hand.

[jimf909]

1 - Your daughter did an informal load test. With the new battery she'll be able to listen to tunes for an hour and the van should start.
2 - Did you ever have this battery load tested (at an auto parts store, not involuntarily by your daughter)? It seems that would have shown weakness. I thought I recall a parts store load test which should have revealed a battery on its last leg, but who knows.
3 - Regardless, if the battery is only charging to 12.3 volts it's only charging to about 65% of a full charge. This is where the hydrometer would show if it's one or two weak cells or all of them. Regardless, as you say, charging to only 12.3 volts means the battery is toast.

[jimf909]