3 weeks ago I bout a new battery, the most expensive one. It was foggy out this morning and I left my lights on. According to my clock in the car it took less than 4 hours to go completely dead. !5 years ago a new battery could go 8 or more hours and still start the car. Is there some ecological reason they are junk now?
Draw vs capacity.
How many amp hours was the old battery vs new battery?
I didn’t check but I should have. The old battery lasted 13 years. The auto parts guy told me it was the longest he had seen.
I do plan to check the amp hour tomorrow and if it doesn’t add up exchange it. 175.00
Whoa 13 years?
We’re mixing attributes.
Draining a battery a few hours faster is about draw and capacity. How long it lasts, in years, is different.
You’re confusing better and bigger.
If you drain a fuel tank before the job is finished the capacity is insufficient. If it starts leaking it’s defective.
I buy crappy Walmart batteries. They have a 3 year free replacement then 2 year pro-rated warranty.
They seem to fail with depressing regularity at 3 years and two weeks. And then they prorate to nothing. :mad:
So, I’m starting to paperclip the receipts to my calendar and …. something.
I am not confusing anything, I am just saying my old battery could handle the lights for a full 9 hours( A work shift) and I commented it lasted 13 years.
You got lucky with one battery. That’s not evidence of anything.
I have never owned a car/battery that could still start after leaving the lights on for more than 4 hours. Leaving the lights on for that long will kill just about any battery in just about any car made in the past half a century. Having a car start after 8 hours is rather remarkable, unless you have a car that automatically shuts off the lights if you accidentally leave them on.
Batteries do tend to suck a bit these days, mostly because they put the smallest battery possible in the car to save weight and space. Some cars are so packed under the hood that you can’t put a larger battery in there even if you want to. If you have the space, you can put a larger battery in there. Not only will it last a bit longer if you leave the lights on (though probably not 8 hours), the battery will last longer in the long term as well. Instead of lasting 3 to 5 years, you can probably get a decade or more out of it fairly easily.
I have oversize batteries in all of my vehicles (except motorcycles), partly so that they’ll last longer, and partly so that they’ll have enough power to start the vehicle even if everything has been sitting for a while in the dead of winter during a cold snap.
I’ve gotten to appreciate GMs method of putting the battery in the trunk next to the spare tire. Accessing the wires for disconnecting and adding electronics is much simpler than routing the wiring around the engine block. I haven’t had to replace one yet so I don’t now if I can go physically larger or not.
I don’t have a cite for this, but I’ve heard today’s batteries suck due to the CCA wars.
CCA = cold cranking amps. More is better, and it’s heavily used in advertising. For a given volume, the only way to increase a battery’s CCA is to increase the surface area of the electrodes (plates). And the only way to increase the surface area of the plates is to use more plates. And if you want to use more plates, each plate must be thinner, obviously. Thin plates corrode much more quickly compared to thick plates.
Again, this is just something I heard a few years back. Not sure how much truth there is in it.
This is pure nonsense. I don’t know if your battery lasted 13 years or not (which would be extraordinary) but no 12 volt automotive lead-acid starter battery is intended for constant service for hours on end and they are not intended for applications with deep discharge cycles. They are intended to provide the brief high amperage load to drive a car engine to initial combustion.
Although electrode corrosion can cause battery failure, the most common causes are electrolyte/water leakage and acid stratification. The thickness of electrodes does not effect their tendency to corrode but thinner plates may warp under high thermal loads and deep discharge cycles, potentially resulting in internal faults.
If batteries are less reliable than in the past (which I find no evidence of) itis due to the fact that modern cars have more accessories and draw more load than in the past.
Stranger
Here is my understanding of it (and I always kinda sucked at chemistry, so take this with a grain of salt).
Thin plates don’t hold as much total charge (obviously), so cranking away that them discharges them more compared to their total capacity than cranking away at thicker plates does. That deeper discharge allows more sulfate crystals to form, and when you have more crystals and larger crystals, they don’t all break up when the battery is charged, leading to permanent plate sulfation and a loss of total capacity. So it’s not corrosion as much as it is sulfation.
Then again, corrosion might just be a slightly less precise way to refer to sulfation, so we might be essentially saying the same thing.
I have read conflicting data about whether stratification is actually a problem or not in automobile batteries.
Stratification is definitely a thing. Large lead-acid batteries, like those used for battery backup in large facilities, definitely suffer from stratification, and many of these larger battery systems actually contain stirring rods which are turned on periodically to stir up the acid and prevent stratification. The long and short of it is that no one really denies that stratification is a thing.
The debate is whether or not automobile batteries are large enough to suffer from this effect to any significant degree, and whether a car that is driven as rarely as once a month or so moves around enough to stir up the acid to prevent stratification.
While battery university is a pretty good site, I’d like to see something more technical and detailed that talks about why this is a problem in automobile batteries. With my only knowledge of the topic being what I have read about it, I’m kinda on the side of it probably not being a problem unless a car sits for months on end. I have never seen any cite that specifies how long it takes for the acid in an automobile sized battery to stratify and cause issues.
plate shedding and mechanical damage (vibration/shock) are the usual killers of car lead-acid batteries. repeated over-discharge will rapidly accelerate plate shedding.
But doesn’t the energy for the loads come from the alternator, not the battery? 
I remember batteries used to be sold as “x-month” batteries (e.g. 50-month, 60-month, etc.) implying that’s how long they would last.
So we would start to look for a new battery as we drew near to the “x-month”.
Now, batteries seem tp be sold more on their capaciry and you’re left on your own to figure out how long the battery will last. I would guess
for the average driver 5 years would be a good time to replace the battery.
Also, if you’re still using old school flooded cell batteries (i.e. removable caps, check/fill cells) you can use a hydrometer to check the state of your
battery.
I remember reading, a long time ago, that there was a move for a 48VDC battery for cars and trucks.
I guess that was voted down. Seemed like a good solution.
It’s coming, but slowly. Requires changing…everything.
42/48 volt has additional safety implications for interior wiring.
When the engine is running but many cars have accessories that operate when the car isn’t running or even when the ignition is off.
Stranger
Two thoughts about that.
First, don’t most cars have an auto-shutoff if the trunk or a door is left open for a long time (mine does)?
I have left a light on for over 24 hours and the car started up right away, probably because the protective circuitry prevented a severe battery discharge.
Conversely, I ran the radio in my (2 year-old) car as I was packing up for a trip. Must have been no more than 45 minutes. When I tried to start it, nothing. I had to call AAA to get on the road.
My conclusion is that although protective circuitry is great, it doesn’t cover all events, and the battery capacity of my car is so small that the protective circuitry is relied upon rather than using a bigger battery.