Does a bigger battery reallly last longer?

[mechanicx]

I'd think a bigger size battery potentially could last longer, but does it really make any difference in the real world? It seems like in a given use they're going to last say 5 years like clock work regardless.


Sometimes you can fit a different group size battery in a given car. A good example is W-bodies that have group 78 but the slightly shorter group 75 is actually a better fit. I know some people just use the 75 because the 78 is all kinds of difficult squeezing in an out past some rather expensive electrical components. Not to mention the 75 is lighter, and about $10 less expensive.

Doesn't time, cycling and imperfect recharging by the alternator make the service life pretty much equal? In other words the 78 has say 10-15% more current capacity but after about 5 years it's going to die too? Or maybe it nominally last 10%/6 months longer, but is 10% more expensive making it about even with the drawback of worse fit and more weight?

 

[Donald]

What should last the longest is the minimum CCA needed for your vehicle in the largest footprint that will fit. Those plates should be strongest.

But sometimes the "gold" model only comes in higher CCA than does the "silver" model.

And while Interstate has a zillion batteries in their catalog good luck finding the less popular ones and they may be more $$ for less CCA as they are special order and not normally stocked.

 

[FZ1]

Bigger is better re battery life. Trust me,I fish.

 

[mechanicx]

Originally Posted By: Donald
What should last the longest is the minimum CCA needed for your vehicle in the largest footprint that will fit. Those plates should be strongest.

But sometimes the "gold" model only comes in higher CCA than does the "silver" model.

And while Interstate has a zillion batteries in their catalog good luck finding the less popular ones and they may be more $$ for less CCA as they are special order and not normally stocked.



This is what I suspect. The top of the line bigger group 78 has 800 CCA, and the equivalent smaller group 75 have 700 CCA. So the batteries have essentially the same service life and the higher amps is not needed. You're just paying extra for something that realizes no benefit, maybe.

 

[mrsilv04]

Originally Posted By: FZ1
Bigger is better re battery life. Trust me,I fish.


That's not the question being asked...

 

[eljefino]

I like the way you think.

IMO, if you can get a slightly smaller battery that's also a very common size you'll get a fresher one, and they'll have perfected the process in their factory due to responses from warranty concerns.

OTOH if they're cheapening the process, like is believed currently, something esoteric and old stock might be better.

With gear reduction starters, batteries don't need the stones they used to have. OTOH their extra capacity runs all the keep-alive currents, so if you let it sit a week regularly you want the full size one.

 

[Rand]

physical size large with less plates -- ie lower CCA will last longest usually.

 

[mongo161]

For a nice long life and powerful battery you can take a look at the Sears Platinum.

All I've heard is raves about this battery.

 

[oldhp]

I was always told the higher the reserve capacity, the better.
CCA's are the initial bang, RC's are how long it will crank, or power car if alt quits. This is a good read.
batteryuniversity.com/index.php/learn/article/starting

 

[mechanicx]

Good replies.


Originally Posted By: Rand
physical size large with less plates -- ie lower CCA will last longest usually.


That's what I'm thinking. Battery makers just advertise for CCA, they don't even want to display reserve capacity. They just jack up the CCA with the bigger more expensive battery more than needed and the battery lasts no longer, just heavier, bulkier and more expensive.

But I don't consider myself any authority on battery tech. I just hadn't notice bigger higher CCA batteries lasting longer.

 

[LeakySeals]

Bigger in what way? Like an oversized oil filter? Or more amps than OE? Funny Gold is mentioned, I have maybe 10 Duralast Gold batteries installed in various cars, one is now 7yrs old. The cranking amps on the Golds are more than the OE, not one failure so far. Not sure there is any correlation though. Could be me feeling responsible occasionally cleaning posts, terminals, oiling, checking water when I see the family cars. Note: Its gotta have that Gold top! Don't let AZ trick you and sell the lesser one. Happened twice, 2 diff stores!

 

[Lakersguy]

Originally Posted By: mongo161
For a nice long life and powerful battery you can take a look at the Sears Platinum.

All I've heard is raves about this battery.


+1 Big time!

 

[JHZR2]

Depends upon what you're doing. The reality is that the narrower the range of conditions that you subject the chemistry, the better.

However, you're balancing that with side reactions that are degrading the chemistry no matter how the battery is used, and only Arrhenius governs that (faster the warmer the battery exists at).

So a bigger battery will deplete less per use, and thus not be as prone, theoretically, to being as undercharged. Additionally, the impedance is lower so the temporary voltage under any load will be higher, which is good.

But again, side reactions don't stop ever, they degrade, and unless you can ensure that the battery is always around 75F or lower and on a float charger, conditions won't be optimal. So they will degrade and then you have the same issues as ever. But being bigger (more energy and less impedance), and given that even the smallest batteries are oversized for most starting requirements, you may cloak a degradation behavior longer because the bigger battery will squeeze a few more amps a few more times.

So I'd go largest that you can find for a reasonably closes price. I wouldn't go after a battery costing 50% more though...

 

[LeakySeals]

Always feel like my dad is talking to me when you reply. Not in a scolding or bad way, a decisive way that you don't question, assume is right.

 

[mechanicx]

Originally Posted By: JHZR2
Depends upon what you're doing. The reality is that the narrower the range of conditions that you subject the chemistry, the better.

However, you're balancing that with side reactions that are degrading the chemistry no matter how the battery is used, and only Arrhenius governs that (faster the warmer the battery exists at).

So a bigger battery will deplete less per use, and thus not be as prone, theoretically, to being as undercharged. Additionally, the impedance is lower so the temporary voltage under any load will be higher, which is good.

But again, side reactions don't stop ever, they degrade, and unless you can ensure that the battery is always around 75F or lower and on a float charger, conditions won't be optimal. So they will degrade and then you have the same issues as ever. But being bigger (more energy and less impedance), and given that even the smallest batteries are oversized for most starting requirements, you may cloak a degradation behavior longer because the bigger battery will squeeze a few more amps a few more times.

So I'd go largest that you can find for a reasonably closes price. I wouldn't go after a battery costing 50% more though...


But I wonder in all that is if the bigger battery is designed to just boost CCA that weren't needed, in the real world does it gain no real service life. It doesn't seem like the next size up batteries last any longer in reality due to boosted CCA and RA not being higher but I could be wrong.

 

[mechanicx]

I've also noticed that Japanese cars often use smaller batteries and with the same replacement battery line, they seem to last as long as the larger ones used in other makes. The 75 series is a good size battery and 78 is a few inches longer and borderline huge. Does it real gain service life being bigger? I'm not so sure.

 

[CATERHAM]

Personally I choose the smallest battery basically to save weight.
I run a small 15 amp/h motorcycle AGM battery in my Caterham and Lotus, a used Honda battery in my BMW (less than have the size) and the optional smaller battery group (yes it's a weight saving option) in my Porsche. Now they also have the very light lithium- ion battery option for a ridiculous extra $2,000.

I've never noticed shortened battery life using a small battery. The biggest practical factor seems to be the battery's quality in addition to proper maintenance (kept fully charged in infrequently used vehicles) for long battery life.

 

[Garak]

Originally Posted By: mechanicx
But I wonder in all that is if the bigger battery is designed to just boost CCA that weren't needed, in the real world does it gain no real service life.

Anecdotally, what I find is it depends upon how much your usage and application actually "stress" the battery that's in there. If the OEM style battery is undersized for your application or usage patterns, then something a bit bigger should have a longer lifespan. If the battery is overkill in the first place, you're likely not going to see an advantage by going bigger yet.

 

[JHZR2]

Originally Posted By: LeakySeals
Always feel like my dad is talking to me when you reply. Not in a scolding or bad way, a decisive way that you don't question, assume is right.


Batteries are a good chunk of my day job

 

[JHZR2]

Originally Posted By: Garak
Originally Posted By: mechanicx
But I wonder in all that is if the bigger battery is designed to just boost CCA that weren't needed, in the real world does it gain no real service life.

Anecdotally, what I find is it depends upon how much your usage and application actually "stress" the battery that's in there. If the OEM style battery is undersized for your application or usage patterns, then something a bit bigger should have a longer lifespan. If the battery is overkill in the first place, you're likely not going to see an advantage by going bigger yet.


Exactly, well said.

One way Id consider it is this: If one generally drives short spurts, so the battery doesnt always charge fully back up again, a bigger battery will be depleted less per start. That means that it will sulfate less and degrade less due to user/application issues. And the chance of forming irreversible phases of noncoductive lead due to hard use and very low local voltages (excess corrosion) are lower, at least to a point. The clock never stops on the basic actions that will degrade (reactions that degrade the battery), so it depends upon the mechanisms that are the cause of failure.

Also, heat degrades batteries rapidly. The life is halved for every 8 degrees or so over 75F. So depending upon climate and a variety of application aspects, a bigger battery, with more mass, will increase in temperature slower (more thermal mass) than a smaller battery. So for short or moderate length operation, the battery will stay cooler on average, benefiting further.