Well, that escalated quickly...

[joekingcorvette]

Batteries can die with no warning. I prematurely put one in the Jeep GC because its under the passenger seat. No way am I going to be stranded in -25 below zero weather and try to move the seat back without power and change the battery. It's in a difficult spot and hard to remove easily especially if it's freezing cold outside.

 

[Shel_B]

Within the realm of the range of batteries, charging devices (alternator), and load we are talking, nothing in that article would apply (that the alternator can’t adequately charge the battery, the fuse panel can’t handle it, etc.). It is very poorly reasoned. Car manufacturers will use the same alternator and regulator package for a variety of installed batteries, for example. Specific cars will even dictate different batteries are acceptable. One single example, I have a Volvo with the battery compartment specifically constructed to take different batteries from 750 to 1000 CA - all just fine to use with the same alternator, regulator, fuse panel, per the manual.

As a second take, that article is terribly vague, unreferenced, and authored by someone without any evidence of experience, credentials, or authority. I know you are repeating something you’ve heard in good faith. My point is not to inherently contradict you, but to point out that there is just a tremendous amount of wrong advice given out by mechanics, and especially by on-line PAID writers on automotive subjects who don’t have the training to do so. Selling revenue clicks is far more important than getting quality advice for most web sites.

The situation and what I found was posted here so others can learn what I discovered and make up their own minds and perhaps create some discussion. I don't know enough about the subject to even suggest whether this is correct or not, but I do know that there will be those who will comment and offer their knowledge and experience as well as their judgments.

 

[f355spider]

Batteries rarely fail without warning...they are continuously degrading over time. You need a battery tester to monitor this. With all the electronics and such in a modern car, it can simply make it harder to observe the signs.

I haven't been stranded with a battery failure in over 15 years, since I purchased an electronic battery tester. (yes a carbon pile load tester is probably better) By using this tester every 6 to 12 months on my cars and truck, I can catch a battery as it starts getting weaker, and before failure. I break it out at every oil change, or when I am rotating tires, etc. The test only takes a few seconds to set the CCA rating and test.

I have tested batteries that display "weak" and are down over 1/3 their rated capacity and still started and drove fine with no indication they were on the way out. I'm confident they would have left me stranded in a few months if left in service. The best part, is it saves me money in not prematurely or preventively replacing batteries. I can test and confirm they are good and see trends of the CCA is dropping at each test. I kept the factory battery in my 2007 Tundra in service for 14 years, as it continue to exceed its CCA rating. But during one oil change I saw it had dropped about 170 CCA below its rating and showed "weak". It was a daily driver, but went ahead and put it on a battery maintainer overnight and retested. It was still showing "weak" so I replaced it.

The one I have is from Griots Garage, which is just a relabled Schumacher BT175. It has a very simple read out. There are more sophisticated versions than the Schumacher, that rather than just give voltage, CCA and a "good, weak or bad", will give you the actual resistance reading for you to interpet. But I like simple and this works for me. .

 

[vavavroom]

That's more typical of AGMs over standard flooded lead acid. I think more and more people are starting to see this behavior as AGMs have gotten more common these days, though I've had the same happen on occasion with flooded batteries. My experience with AGMs though has been as bad as it started just fine and 10 minutes later after shutting the car off I didn't even have working interior lights. I stopped at McDonalds the last time and I'm glad I used the pickup parking spaces because when I shut the car off to wait it didn't start again.

That sounds about right. I have been replacing AGM batteries at the first sign of decreased performance which has been occurring on average after 7 years. The last battery that died on me unexpectedly was over 20 years ago.

 

[Bladecutter]

Batteries can die with no warning. I prematurely put one in the Jeep GC because its under the passenger seat. No way am I going to be stranded in -25 below zero weather and try to move the seat back without power and change the battery. It's in a difficult spot and hard to remove easily especially if it's freezing cold outside.

Easy solution:

Open car door.
Pop hood.
Connect jumper cables between the new battery, and the jump start points.
Move seat.
Disconnect old battery from car and remove.
Disconnect new battery from jumper cables, and install into car.
Move seat back into position.
Continue on with life.

 

[eljefino]

figure the more the battery is discharged the higher its internal resistance to recharging is..

On a HEALTHY battery this isn't how it is, it would LOVE to recharge and would have an insanely low internal resistance.

One with one foot in the grave, however, under most conditions, would have very high internal resistance and/or very reduced storage capacity. You might notice it starting fine but needing a jump after listening to the radio for five minutes.

 

[MSCH]

On a HEALTHY battery this isn't how it is, it would LOVE to recharge and would have an insanely low internal resistance.

One with one foot in the grave, however, under most conditions, would have very high internal resistance and/or very reduced storage capacity. You might notice it starting fine but needing a jump after listening to the radio for five minutes.

I didn't want to write something so lengthy that I covered all the possibilities
but basically, even a healthy but otherwise dead battery ( somebody left the lights on for a day as an example)
has more internal resistance than a good battery that was more minimally discharged.
that's the charging the alternator is good at, putting a little bit back in that slightly discharged battery.
A battery charger is better at replenishing a really dead butotherwise good battery.

what you are referring to is when the battery has lost capacity or its CCA rating has went down due to degradation of the battery internals
yeah, it still has 2.1vdc per cell when fully charged but it doesn't hold nearly the amount of electrical energy it did when new.
hence it will "recharge" to full voltage in a few minutes time
but if you put a real load on it , it won't supply enough to do the job