At what % CCA do you replace your batteries?

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Oct 30, 2015
Of course, some CCA loss is normal over time. But at what point do you replace the battery? The Sienna battery tested at 501 out of 700 CCA, a loss of 29.5%. It's a 4 year old Autocraft gold. And the Buick battery tested at 499 out of 660 CCA, a loss of 24.4%. It's a 2.5 year old AC Delco Silver. (Both are JCI batteries.) Would you guys replace them or wait?
How do the vehicles act when cranking? Yes, they are loosing starting power, but do they have enough to spin a cold motor well? I've taken 1,000 CCA batteries down to just above 50% and they would still start. But, at that point it was getting sketchy ...
I have no idea about CCA. I change the battery out when the car doesn't start with the same gusto as usual.
I've actually never gotten a battery tested for replacement. I usually replace them when they get slow to crank, or don't crank at all. I mentally factor in the age of the battery as well. If the battery is relatively new, I'll put it on the battery tender a while to see if it improves.
Can you top them with some dist. water? I would do that if possible. Then take them both to Walmart TLE for their NOCO treatment which runs $3.50/battery. They will install the felt washers and some nice thick red grease. Then maybe give them a good charge. I have a 500 CCA battery that is five years old + and tested at 455 CCA. So less than 10% reduction and has never been charged.
The Odyssey AGM (Diehard Plat) in my Silverado tested 835CCA @ 12.2v resting overnight. Made in Nov 2013. ~1300CCA @ 13.06v when purchased brand new. Started looking for a new battery. Had times where it struggled to start.
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Originally Posted By: ZZman
No idea on CCA. I change it when AutoZone test says it is bad.
They always say it's bad it seems. Just like in my example above. They asked for the CCA and it came back at 455/500. I asked one of the most knowledgeable guys on here about it and he said for less than 10% it would be a waste to replace it.
If you ask Midtronics (as approved for battery warranties), <50% is the replace zone and <60% is a warning.
Originally Posted By: TmanP
Would you guys replace them or wait?
I always wait until they get "slow" - usually, there's lot of "warning"' I have only EVER had ONE battery that just up & failed 100% (started perfectly one day, next day = NOTHING) and it was a MAXX-1 Group 65 in my F150. I had to jump it off from my Harley to get to the store.
This one shows no signs of weakness, yet I get this. Not sure what to make of it. Lost capacity If get but it cranks strong and easy even in 10F weather which is the coldest we've seen. I do have a spare battery in reserve.
I usually end up replacing batteries when I begin noticing a combo of capacity drop, slower cranking, or poor charge holding. My car is very reliable and consistent to start, so any weakening is obvious, such as taking a full extra compression stroke to catch in mild weather. But capacity drop, self discharge, or not taking a charge well is the more common red flag, even if it still cranks strong. I don't want to find out the hard way there's only 30 minutes reserve capacity instead of 120.
I think Ford condemns the battery when it loses 20% of original CCA. Whether that's a real rule of thumb or meretricious nonsense, I have no idea. The rationale is that it's hard on the alternator, not that the battery is weak, per se. That's plausible.
I replaced the factory flooded Group 96R battery in my wife's Mustang last month. It was down to about 60% of original rated CCA, and had been in service 7 years. The "eye" was dark. It still cranked her engine over fine, but I no longer trusted it and Pep Boys had an incredible sale + stackable rebate over Black Friday. I upgraded her car to a AGM Group 48 Bosch battery. Glad I did this when I did, before the current extended cold snap.
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Originally Posted By: slacktide_bitog
I replace when it doesn't start the car anymore
Check. Only data I have, but fortunately, it is the most relevant.
Those numbers look bad, JHZR2. If it was my car and battery I'd change it out. I'd be interested in how many amps it takes in as charging right after the start, and for how long, but I know that takes a lot of work. Mainly I'd be concerned with if the battery is overstressing the charging system.
Originally Posted By: slacktide_bitog
I replace when it doesn't start the car anymore
Same. At least a dealership test. AZ told me my batt was dead, had dealer test it and they said it was still good.
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