Car battery replacement interval advice

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sport
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Re: Car battery replacement interval advice

Post by sport »

hudson wrote: Tue Nov 23, 2021 2:27 pm
sport wrote: Tue Nov 23, 2021 12:21 pm
hudson wrote: Tue Nov 23, 2021 12:03 pm Thanks again sport!
So if the 5 year old battery is rated at 710 CCA and the load test at 40 degrees shows 600 CCA...in the green, then I'm OK for a while?
Well, CCA is a rating for 0 degrees F for 30 seconds with the voltage no less than 10.5 volts. I don't know how your load test was run. However, if that is a valid result, the battery is a lot weaker than it was when new. You might be OK for a while. Then again, if you had some really cold weather, you could have a problem. I would say it depends on where you live. In Florida, you could be OK for some time. In North Dakota, I would replace it today.
Thanks Sport! After fully charging the battery, YouTube and I used a $20 Harbor Freight load tester. It was 40 degrees outside. I'm closer to Florida than North Dakota. I do plan on buying a new battery soon. I'm just trying to learn how to evaluate the load test results.
Did the load test last 30 seconds? 600 at 40F is a lot worse than 710 at 0F.
hudson
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Re: Car battery replacement interval advice

Post by hudson »

sport wrote: Tue Nov 23, 2021 2:50 pm
hudson wrote: Tue Nov 23, 2021 2:27 pm
sport wrote: Tue Nov 23, 2021 12:21 pm
hudson wrote: Tue Nov 23, 2021 12:03 pm Thanks again sport!
So if the 5 year old battery is rated at 710 CCA and the load test at 40 degrees shows 600 CCA...in the green, then I'm OK for a while?
Well, CCA is a rating for 0 degrees F for 30 seconds with the voltage no less than 10.5 volts. I don't know how your load test was run. However, if that is a valid result, the battery is a lot weaker than it was when new. You might be OK for a while. Then again, if you had some really cold weather, you could have a problem. I would say it depends on where you live. In Florida, you could be OK for some time. In North Dakota, I would replace it today.
Thanks Sport! After fully charging the battery, YouTube and I used a $20 Harbor Freight load tester. It was 40 degrees outside. I'm closer to Florida than North Dakota. I do plan on buying a new battery soon. I'm just trying to learn how to evaluate the load test results.
Did the load test last 30 seconds? 600 at 40F is a lot worse than 710 at 0F.
No...15 seconds is what the directions called for. I used this tester: https://www.harborfreight.com/100a-612v ... 61747.html
sport
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Re: Car battery replacement interval advice

Post by sport »

hudson wrote: Tue Nov 23, 2021 3:06 pm
sport wrote: Tue Nov 23, 2021 2:50 pm
hudson wrote: Tue Nov 23, 2021 2:27 pm
sport wrote: Tue Nov 23, 2021 12:21 pm
hudson wrote: Tue Nov 23, 2021 12:03 pm Thanks again sport!
So if the 5 year old battery is rated at 710 CCA and the load test at 40 degrees shows 600 CCA...in the green, then I'm OK for a while?
Well, CCA is a rating for 0 degrees F for 30 seconds with the voltage no less than 10.5 volts. I don't know how your load test was run. However, if that is a valid result, the battery is a lot weaker than it was when new. You might be OK for a while. Then again, if you had some really cold weather, you could have a problem. I would say it depends on where you live. In Florida, you could be OK for some time. In North Dakota, I would replace it today.
Thanks Sport! After fully charging the battery, YouTube and I used a $20 Harbor Freight load tester. It was 40 degrees outside. I'm closer to Florida than North Dakota. I do plan on buying a new battery soon. I'm just trying to learn how to evaluate the load test results.
Did the load test last 30 seconds? 600 at 40F is a lot worse than 710 at 0F.
No...15 seconds is what the directions called for. I used this tester: https://www.harborfreight.com/100a-612v ... 61747.html
Well, that is less severe than the standard test. Instead of 710amps for 30 seconds at 0 degrees, you measured 600 amps for 15 seconds at 40 degrees. Since it seems you will need a new battery soon in any case, you may as well get one now, before colder weather arrives. At least, that is what I would do.
hudson
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Re: Car battery replacement interval advice

Post by hudson »

sport wrote: Tue Nov 23, 2021 3:35 pm
hudson wrote: Tue Nov 23, 2021 3:06 pm
sport wrote: Tue Nov 23, 2021 2:50 pm
hudson wrote: Tue Nov 23, 2021 2:27 pm
sport wrote: Tue Nov 23, 2021 12:21 pm Well, CCA is a rating for 0 degrees F for 30 seconds with the voltage no less than 10.5 volts. I don't know how your load test was run. However, if that is a valid result, the battery is a lot weaker than it was when new. You might be OK for a while. Then again, if you had some really cold weather, you could have a problem. I would say it depends on where you live. In Florida, you could be OK for some time. In North Dakota, I would replace it today.
Thanks Sport! After fully charging the battery, YouTube and I used a $20 Harbor Freight load tester. It was 40 degrees outside. I'm closer to Florida than North Dakota. I do plan on buying a new battery soon. I'm just trying to learn how to evaluate the load test results.
Did the load test last 30 seconds? 600 at 40F is a lot worse than 710 at 0F.
No...15 seconds is what the directions called for. I used this tester: https://www.harborfreight.com/100a-612v ... 61747.html
Well, that is less severe than the standard test. Instead of 710amps for 30 seconds at 0 degrees, you measured 600 amps for 15 seconds at 40 degrees. Since it seems you will need a new battery soon in any case, you may as well get one now, before colder weather arrives. At least, that is what I would do.
Many thanks Sport!
New battery soon! It weighs 50 lbs. I'll likely go with a parts store or my trusted local mechanic. I'll have them put the green felt washer on the positive side. :)
sport
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Re: Car battery replacement interval advice

Post by sport »

hudson wrote: Tue Nov 23, 2021 3:58 pm I'll have them put the green felt washer on the positive side.
IMO, those washers may do more harm than good. They are supposed to keep any acid that seeps around the post away from the connector. However, the acid may wick through the washer and reach the connector more than it would without the washer. There may be differences of opinion on that. FWIW, my mechanic does not install those when he puts a new battery in my car.
hudson
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Re: Car battery replacement interval advice

Post by hudson »

Thanks again sport!
I replaced the battery with an AutoZone 27F-EFB...810 CCA at 0 degrees/1010 at 32 CCA degrees battery...too late...washers already installed. I guess that it's a plus that it was maintenance free...no way to add or check fluid?

I asked the installer to check the old battery...result with his AutoZone Starting and Charging Tester: "Good Battery 12.67 V, CHRG 100%." I think that verifies that my cheapo tester was in the ballpark. The installer said that his tester would not show CCAs.

Bottom Line: That should give me 4+ good years.
sport
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Re: Car battery replacement interval advice

Post by sport »

hudson wrote: Tue Nov 23, 2021 5:41 pm Thanks again sport!
I replaced the battery with an AutoZone 27F-EFB...810 CCA at 0 degrees/1010 at 32 CCA degrees battery...too late...washers already installed. I guess that it's a plus that it was maintenance free...no way to add or check fluid?

I asked the installer to check the old battery...result with his AutoZone Starting and Charging Tester: "Good Battery 12.67 V, CHRG 100%." I think that verifies that my cheapo tester was in the ballpark. The installer said that his tester would not show CCAs.

Bottom Line: That should give me 4+ good years.
The test at AutoZone apparently was just a voltmeter. All that tells you is the battery was charged. Maintenance free batteries may, or may not be sealed. Since yours is "sealed", you cannot check the electrolyte nor add water. However, you should not need to. The idea is that the water usage is so low, the battery will die of old age before more water would be needed. Actually, it is not really sealed. It must have a vent to let gasses out. It is possible to seal a lead acid battery, but that would be an unnecessary extra cost.
talzara
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Re: Car battery replacement interval advice

Post by talzara »

hudson wrote: Tue Nov 23, 2021 5:41 pm I asked the installer to check the old battery...result with his AutoZone Starting and Charging Tester: "Good Battery 12.67 V, CHRG 100%." I think that verifies that my cheapo tester was in the ballpark. The installer said that his tester would not show CCAs.
sport wrote: Tue Nov 23, 2021 7:11 pm The test at AutoZone apparently was just a voltmeter. All that tells you is the battery was charged.
It is not just a voltmeter, and it tells you a lot more than the battery charge.

The AutoZone Starting and Charging Tester is an electrical system analyzer that's manufactured by Auto Meter and costs over $1,000. When used in battery testing mode, it measures the impedance and calculates the CCA, just like other "conductance" testers.

Auto Meter's latest products have a four-line LCD display, and the calculated CCA is displayed on the 4th line. AutoZone may have bought an older version that doesn't have four lines. "Good Battery 12.67 V, CHRG 100%" is the same format that is displayed on lines 2-3 of the four-line models. See page 12 of the Auto Meter BVA-260 manual: https://www.autometer.com/pub/media/man ... 0-1418.pdf

Industrial electronics cost a lot more than consumer electronics. Midtronics still makes an impedance tester that only has three LEDs to show good/bad/low voltage! The PBT-100 costs almost $200 and has a 7-segment LED display, but it can only display voltage. It calculates CCA and determines battery health, but it cannot display the CCA. To get that capability, you have to step up to the PBT-200. Here's the brochure for the PBT series: https://www.midtronics.com/wp-content/u ... ochure.pdf
sport
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Re: Car battery replacement interval advice

Post by sport »

hudson wrote: Tue Nov 23, 2021 5:41 pm The installer said that his tester would not show CCAs.
talzara wrote: Tue Nov 23, 2021 11:18 pm Auto Meter's latest products have a four-line LCD display, and the calculated CCA is displayed on the 4th line.
Something does not match up here.
hudson
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Re: Car battery replacement interval advice

Post by hudson »

AutoZone battery tester:
I took a picture of the tester my installer used.
It's an "AutoZone Starting & Charging Tester." I only got a partial model number...the bottom was cut off. It looks like FSD-2010, but it could be ESP-3010? (EDIT: It's ESD-2010) It has vents and what looks like coils inside.
When the installer tested it, it got hot. The installer said that it tests load but does not display load results.
The exact display was
"#3186 12V BATT.
GOOD BATTERY
12.67V CHRG 100%
'Y' TO CONTINUE"

It also says: "FOR TECHNICAL ASSISTANCE CALL 888-453-2244"

Not my picture; but this is the tester the installer used: https://www.yelp.com/biz_photos/autozon ... wdF_29GSlw
dbr
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Re: Car battery replacement interval advice

Post by dbr »

I don't suppose "Y continue" would display more results?
hudson
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Re: Car battery replacement interval advice

Post by hudson »

dbr wrote: Wed Nov 24, 2021 10:06 am I don't suppose "Y continue" would display more results?
dbr,
I asked the same thing; the installer who had been working there for 4 years said that that tester did not display CCAs. He did comment that the battery was heavy.
keystone
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Re: Car battery replacement interval advice

Post by keystone »

sandan wrote: Sun Nov 21, 2021 3:00 pm
Afty wrote: Sun Nov 21, 2021 1:55 pm Thanks to this thread, I bought a $30 car battery tester from Amazon. It works well, and I no longer have to guess about the health of our car batteries, especially since one of our cars is rarely driven. Thanks to the above posters who recommended this!
Ditto. I bought one last week as well. Higher battery prices and remote work has made this a no brainer. It seems like people working from home should be doing battery checks even if their battery is new.

No point in throwing out a perfectly fine battery.
Same here. After reading this thread, I bought the $30 tester and now it's really nice to have assurance that my battery is good. I used to replace like clockwork every 4 years, but now I will just rely on periodic tests.

One thing that I noticed was that my SOC was at 1%. I guess that means I should drive it around for more than a short trip the next time out?
talzara
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Re: Car battery replacement interval advice

Post by talzara »

sport wrote: Wed Nov 24, 2021 9:37 am
talzara wrote: Tue Nov 23, 2021 11:18 pm Auto Meter's latest products have a four-line LCD display, and the calculated CCA is displayed on the 4th line.
Something does not match up here.
hudson wrote: Wed Nov 24, 2021 9:52 am It's an "AutoZone Starting & Charging Tester." I only got a partial model number...the bottom was cut off. It looks like FSD-2010, but it could be ESP-3010? (EDIT: It's ESD-2010)
Here is the manual for the Auto Meter AutoZone ESD-2010: https://usermanual.wiki/m/5c0ee4e2b0f36 ... 4c34ca.pdf

The specs are exactly the same as the BVA-260. However, the AutoZone tester is running different software that does not display CCA on the 4th line. It runs the same tests and calculates CCA, but it just won't show it to you.

As you can see on page 12 of the manual, the original software left the fourth line blank for good batteries. There's room to display the CCA, but it displayed nothing rather than show it to you. There must've been a software update that changed the fourth line to display "'Y' TO CONTINUE."

It probably helps AutoZone sell more batteries. Many people don't understand that batteries testing below 70% of rated CCA should be replaced. If they see 69% of rated CCA, they may decide that the battery is still 69% good rather than past end-of-life. If they only see "BAD BATTERY," then they are more likely to buy a new battery.
talzara
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Re: Car battery replacement interval advice

Post by talzara »

keystone wrote: Wed Nov 24, 2021 11:12 am Same here. After reading this thread, I bought the $30 tester and now it's really nice to have assurance that my battery is good. I used to replace like clockwork every 4 years, but now I will just rely on periodic tests.

One thing that I noticed was that my SOC was at 1%. I guess that means I should drive it around for more than a short trip the next time out?
If your state of charge is at 1%, then you should charge it first and test it again. Battery impedance test results vary with voltage, so they are unreliable at low charge. I'm surprised the battery tester didn't tell you to charge the battery first before testing.
keystone
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Re: Car battery replacement interval advice

Post by keystone »

talzara wrote: Wed Nov 24, 2021 1:23 pm
keystone wrote: Wed Nov 24, 2021 11:12 am Same here. After reading this thread, I bought the $30 tester and now it's really nice to have assurance that my battery is good. I used to replace like clockwork every 4 years, but now I will just rely on periodic tests.

One thing that I noticed was that my SOC was at 1%. I guess that means I should drive it around for more than a short trip the next time out?
If your state of charge is at 1%, then you should charge it first and test it again. Battery impedance test results vary with voltage, so they are unreliable at low charge. I'm surprised the battery tester didn't tell you to charge the battery first before testing.
Thanks, yeah I ended up getting the "Good-Recharge" result, but I will try again after a good charge.
sandan
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Re: Car battery replacement interval advice

Post by sandan »

keystone wrote: Wed Nov 24, 2021 11:12 am
sandan wrote: Sun Nov 21, 2021 3:00 pm
Afty wrote: Sun Nov 21, 2021 1:55 pm Thanks to this thread, I bought a $30 car battery tester from Amazon. It works well, and I no longer have to guess about the health of our car batteries, especially since one of our cars is rarely driven. Thanks to the above posters who recommended this!
Ditto. I bought one last week as well. Higher battery prices and remote work has made this a no brainer. It seems like people working from home should be doing battery checks even if their battery is new.

No point in throwing out a perfectly fine battery.
Same here. After reading this thread, I bought the $30 tester and now it's really nice to have assurance that my battery is good. I used to replace like clockwork every 4 years, but now I will just rely on periodic tests.

One thing that I noticed was that my SOC was at 1%. I guess that means I should drive it around for more than a short trip the next time out?
I have a $15 amazon basic battery trickle charger (that is supposed to be smart). It seems to serve me well (a household with 2 WFH cars). We also live less than mile away from any store we need to go to.
hudson
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Re: Car battery replacement interval advice

Post by hudson »

talzara wrote: Wed Nov 24, 2021 1:06 pm
It probably helps AutoZone sell more batteries.
Many people don't understand that batteries testing below 70% of rated CCA should be replaced.
If they see 69% of rated CCA, they may decide that the battery is still 69% good rather than past end-of-life. If they only see "BAD BATTERY," then they are more likely to buy a new battery.
talzara,
In my case, my 4+ year old and fully charged 710 CCA rated battery load-tested at 600 CCA.
70% of 710 is 497 CCA. According to the above guideline, the battery is OK. My cheapo tester and AutoZone's tester indicated that the battery was OK.
Would you say that it has about a year of life left...or would you re-check in 6 months?

It's all moot because I replaced the battery. I'm asking for educational purposes.
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willthrill81
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Re: Car battery replacement interval advice

Post by willthrill81 »

hudson wrote: Thu Nov 25, 2021 7:04 pm
talzara wrote: Wed Nov 24, 2021 1:06 pm
It probably helps AutoZone sell more batteries.
Many people don't understand that batteries testing below 70% of rated CCA should be replaced.
If they see 69% of rated CCA, they may decide that the battery is still 69% good rather than past end-of-life. If they only see "BAD BATTERY," then they are more likely to buy a new battery.
talzara,
In my case, my 4+ year old and fully charged 710 CCA rated battery load-tested at 600 CCA.
70% of 710 is 497 CCA. According to the above guideline, the battery is OK. My cheapo tester and AutoZone's tester indicated that the battery was OK.
Would you say that it has about a year of life left...or would you re-check in 6 months?

It's all moot because I replaced the battery. I'm asking for educational purposes.
I would have hung on to the battery for at least another year, though getting it re-tested every six months wouldn't be a bad idea.

As I noted above, the OEM battery in our SUV only lasted three years before it needed replacement. The parasitic loads placed on modern vehicles seem likely to blame.
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hudson
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Re: Car battery replacement interval advice

Post by hudson »

willthrill81 wrote: Thu Nov 25, 2021 8:46 pm
I would have hung on to the battery for at least another year, though getting it re-tested every six months wouldn't be a bad idea.

As I noted above, the OEM battery in our SUV only lasted three years before it needed replacement. The parasitic loads placed on modern vehicles seem likely to blame.
Thanks willthrill81!
The last time I replaced the battery in that truck (4+ years ago), I kept the old battery and put it in an even older truck. It was a little to big for the battery box, but the hold-downs kept it from moving. It served me well and was still going strong about a year later when I sold the old truck.

Bottom line: For my "new" truck, no battery issues...9 years.
Last edited by hudson on Fri Nov 26, 2021 8:40 am, edited 1 time in total.
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jabberwockOG
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Re: Car battery replacement interval advice

Post by jabberwockOG »

Just replaced my battery. At startup I noticed a slight slowdown in the rate the starter turned the engine. Engine start went from less than 1/2 second to maybe 3/4-1 second - so change was slight but noticeable to someone vary familiar with the car.

A slight decrease in starter speed/engine start up is about all the early notice modern batteries will give a driver before relatively soon they leave you stranded.

Drove over to walmart for another Evermax battery. They quickly replaced the battery in and out in less than 1 hour. Walmart gave me about 50% warranty credit for the old battery (just over 3 years old). Walmart sells/installs a ton of batteries so they usually have very fresh stock.
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blaugranamd
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Re: Car battery replacement interval advice

Post by blaugranamd »

Replacing batteries at regular intervals is excessive. If you're getting hard starts, get it tested at one of the thousands of places that test, sell, and rellat batteries for free. Some of you clearly have inexpensive batteries. Truck batteries run near $300.

We've put Optima Reds in our Subarus in the Midwest and they have lasted 8+ years without issue.
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dbr
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Re: Car battery replacement interval advice

Post by dbr »

blaugranamd wrote: Fri Nov 26, 2021 9:39 am Replacing batteries at regular intervals is excessive. If you're getting hard starts, get it tested at one of the thousands of places that test, sell, and rellat batteries for free. Some of you clearly have inexpensive batteries. Truck batteries run near $300.

We've put Optima Reds in our Subarus in the Midwest and they have lasted 8+ years without issue.
AGM type batteries are probably a good idea. The plan would be to pay more and replace batteries less often.
Reubin
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Re: Car battery replacement interval advice

Post by Reubin »

I was reading this thread and then my battery went dead. Thanks, guys!
tibbitts
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Re: Car battery replacement interval advice

Post by tibbitts »

blaugranamd wrote: Fri Nov 26, 2021 9:39 am Truck batteries run near $300.
I didn't think conventional batteries for trucks cost more than for other vehicles, unless possibly you are multiplying by the number of batteries required. Regarding AGM, I'm not sure most people want to deal with installing an AGM battery in a vehicle that wasn't designed for at least the choice of using one.
sport
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Re: Car battery replacement interval advice

Post by sport »

tibbitts wrote: Fri Nov 26, 2021 12:37 pm
blaugranamd wrote: Fri Nov 26, 2021 9:39 am Truck batteries run near $300.
I didn't think conventional batteries for trucks cost more than for other vehicles, unless possibly you are multiplying by the number of batteries required. Regarding AGM, I'm not sure most people want to deal with installing an AGM battery in a vehicle that wasn't designed for at least the choice of using one.
Well, there are trucks and then there are TRUCKS. Large diesel trucks use a very large battery.
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Re: Car battery replacement interval advice

Post by tibbitts »

sport wrote: Fri Nov 26, 2021 12:41 pm
tibbitts wrote: Fri Nov 26, 2021 12:37 pm
blaugranamd wrote: Fri Nov 26, 2021 9:39 am Truck batteries run near $300.
I didn't think conventional batteries for trucks cost more than for other vehicles, unless possibly you are multiplying by the number of batteries required. Regarding AGM, I'm not sure most people want to deal with installing an AGM battery in a vehicle that wasn't designed for at least the choice of using one.
Well, there are trucks and then there are TRUCKS. Large diesel trucks use a very large battery.
I thought group 31 was common in large trucks, and is only marginally bigger and not significantly more expensive than the common group 27 used in many automobiles.
sport
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Re: Car battery replacement interval advice

Post by sport »

tibbitts wrote: Fri Nov 26, 2021 1:21 pm
sport wrote: Fri Nov 26, 2021 12:41 pm
tibbitts wrote: Fri Nov 26, 2021 12:37 pm
blaugranamd wrote: Fri Nov 26, 2021 9:39 am Truck batteries run near $300.
I didn't think conventional batteries for trucks cost more than for other vehicles, unless possibly you are multiplying by the number of batteries required. Regarding AGM, I'm not sure most people want to deal with installing an AGM battery in a vehicle that wasn't designed for at least the choice of using one.
Well, there are trucks and then there are TRUCKS. Large diesel trucks use a very large battery.
I thought group 31 was common in large trucks, and is only marginally bigger and not significantly more expensive than the common group 27 used in many automobiles.
Well, it has been a very long time since I was in that business, so some things probably changed. However, I do remember some very large truck batteries. I don't recall the group size.
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Electron
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Re: Car battery replacement interval advice

Post by Electron »

If anyone is taking measurements over time relating to battery condition, I would suggest taking readings at approximately the same temperature each time. Lead acid batteries are quite sensitive to temperature.

I have been taking periodic readings on my 2016 battery with one of the SOLAR conductance testers. The hope is that a drop in CCA capacity of some percentage would be a warning to replace the battery. As of November 2020, the indicated capacity has dropped only a very small percentage. I plan to take another reading soon. This car has seen very little use over the last several years and a battery tender is connected most of the time.
Electron
hudson
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Re: Car battery replacement interval advice

Post by hudson »

Electron wrote: Fri Nov 26, 2021 6:05 pm If anyone is taking measurements over time relating to battery condition, I would suggest taking readings at approximately the same temperature each time. Lead acid batteries are quite sensitive to temperature.

I have been taking periodic readings on my 2016 battery with one of the SOLAR conductance testers. The hope is that a drop in CCA capacity of some percentage would be a warning to replace the battery. As of November 2020, the indicated capacity has dropped only a very small percentage. I plan to take another reading soon. This car has seen very little use over the last several years and a battery tender is connected most of the time.
Above talzara said,
Many people don't understand that batteries testing below 70% of rated CCA should be replaced.
I wonder if there is a source, manual, or industry standard that speaks to that?
sandan
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Re: Car battery replacement interval advice

Post by sandan »

hudson wrote: Fri Nov 26, 2021 6:52 pm
Electron wrote: Fri Nov 26, 2021 6:05 pm If anyone is taking measurements over time relating to battery condition, I would suggest taking readings at approximately the same temperature each time. Lead acid batteries are quite sensitive to temperature.

I have been taking periodic readings on my 2016 battery with one of the SOLAR conductance testers. The hope is that a drop in CCA capacity of some percentage would be a warning to replace the battery. As of November 2020, the indicated capacity has dropped only a very small percentage. I plan to take another reading soon. This car has seen very little use over the last several years and a battery tender is connected most of the time.
Above talzara said,
Many people don't understand that batteries testing below 70% of rated CCA should be replaced.
I wonder if there is a source, manual, or industry standard that speaks to that?
I was curious about this comment as well. All I've read so far is 50% or a cca specific to each car.
hudson
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Re: Car battery replacement interval advice

Post by hudson »

sandan,
I speculate for most folks that use testers every day, they just go with what the tester says.
If the (load) tester indicates PASS, the battery is good.
If the tester indicates FAIL or words to that effect, it's time to replace.
If the testing indicator is very close to the fail mark, don't go on a cross country trip with that battery.
Last edited by hudson on Sat Nov 27, 2021 7:44 am, edited 1 time in total.
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Electron
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Re: Car battery replacement interval advice

Post by Electron »

hudson wrote: Fri Nov 26, 2021 6:52 pm
Above talzara said,
Many people don't understand that batteries testing below 70% of rated CCA should be replaced.
I wonder if there is a source, manual, or industry standard that speaks to that?
I don't have the answer to your question but will mention a couple of considerations.

Every vehicle typically has a recommended CCA rating for the battery. It wouldn't be a good idea to drop significantly below that rating. The vehicle might not start at low temperatures. In addition, less capacity might result in additional wear on the starter.

The 70% figure that has been mentioned may come in part from actual experience. Car batteries can fail suddenly and that is one thing we'd like to avoid.

Lead acid batteries have an unused space at the bottom of every cell. Material shed by the plates can eventually short circuit a cell. I heard years ago that the height of that space may vary with the warranty period for the battery.

Another factor is that loss of capacity may accelerate as the battery ages.
Electron
sport
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Re: Car battery replacement interval advice

Post by sport »

Electron wrote: Fri Nov 26, 2021 11:34 pm Lead acid batteries have an unused space at the bottom of every cell. Material shed by the plates can eventually short circuit a cell. I heard years ago that the height of that space may vary with the warranty period for the battery.
When I worked in that industry, we field tested batteries in actual use, and then did "tear-downs" to determine the cause failure. The most common cause of failure was grid corrosion. This is when the lead grid in the positive plate become converted from metallic lead to PbO2 which is the active material in the positive plate. Since PbO2 is a poor conductor of electricity, this conversion causes the internal resistance of the battery to increase which in turn lowers the CCA. The second most common failure mode was a short circuit through a separator. I do not remember ever seeing a battery fail from active material shedding into the bottom of the cells. Generally, the warranty period is determined by the size and number of plates. More plates and larger plates will provide longer life and the warranties are consistent with this. There may be exceptions where the longer warranty just means a higher selling price. However, that is not very common in my experience.

The ribs at the bottom of the cells have a length so that the top of the plates sits at the proper location for assembly. So, the batteries with the most space at the bottom have the shortest plates and thus the shorter warranties. Conversely, the batteries with the larger plates will have less space at the bottom, but will have the longer warranties.
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Re: Car battery replacement interval advice

Post by willthrill81 »

sport wrote: Sat Nov 27, 2021 12:07 am
Electron wrote: Fri Nov 26, 2021 11:34 pm Lead acid batteries have an unused space at the bottom of every cell. Material shed by the plates can eventually short circuit a cell. I heard years ago that the height of that space may vary with the warranty period for the battery.
When I worked in that industry, we field tested batteries in actual use, and then did "tear-downs" to determine the cause failure. The most common cause of failure was grid corrosion. This is when the lead grid in the positive plate become converted from metallic lead to PbO2 which is the active material in the positive plate. Since PbO2 is a poor conductor of electricity, this conversion causes the internal resistance of the battery to increase which in turn lowers the CCA. The second most common failure mode was a short circuit through a separator. I do not remember ever seeing a battery fail from active material shedding into the bottom of the cells. Generally, the warranty period is determined by the size and number of plates. More plates and larger plates will provide longer life and the warranties are consistent with this. There may be exceptions where the longer warranty just means a higher selling price. However, that is not very common in my experience.

The ribs at the bottom of the cells have a length so that the top of the plates sits at the proper location for assembly. So, the batteries with the most space at the bottom have the shortest plates and thus the shorter warranties. Conversely, the batteries with the larger plates will have less space at the bottom, but will have the longer warranties.
Very interesting. Thanks for sharing your professional expertise and experience.

Is grid corrosion mostly a result of the lead acid battery having been 'used up' (i.e., reached the expected end of its cycle life)?
“Good and ill have not changed since yesteryear; nor are they one thing among Elves and Dwarves and another among Men.” J.R.R. Tolkien, The Lord of the Rings
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Re: Car battery replacement interval advice

Post by sport »

willthrill81 wrote: Sat Nov 27, 2021 10:34 am Is grid corrosion mostly a result of the lead acid battery having been 'used up' (i.e., reached the expected end of its cycle life)?
The short answer is yes, although it is mileage, not cycle life. The explanation is that normal charging voltage has to be high enough to ensure a full charge. To prevent undercharging the battery, there is a small amount of overcharge. When a battery is charged, the active material in the positive plate is converted from lead sulfate,PbSO4, to lead peroxide, PbO2. When the battery is overcharged, some of the metallic lead in the positive grid is also converted into PbO2. This is why a battery can fail due to high mileage. The active material in the negative plate is converted from PbSO4 to metallic lead, so that grid is unaffected.

Evidence of this effect is shown in the warranty on batteries used in commercial trucks which operate almost 24/7. When I was in that business, the warranty was something like 90 days or 100K miles, whichever came first. :shock:
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Re: Car battery replacement interval advice

Post by talzara »

hudson wrote: Fri Nov 26, 2021 6:52 pm
Many people don't understand that batteries testing below 70% of rated CCA should be replaced.
I wonder if there is a source, manual, or industry standard that speaks to that?
The auto industry can't even decide whether tires should be replaced after 6 years or 10 years. Standardizing on a battery replacement CCA will be even more difficult. Tires can blow out and cause fatal crashes, but batteries just prevent the car from starting.

You can use 70%, 80%, or any other number. However, most battery testers will tell you to replace at 70%, and most car mechanics use these testers. AutoZone is also using a tester that recommends replacement at 70%.

Take a look at pages 11-12 of the manual for the Auto Meter BVA-260, which has exactly the same specs as the AutoZone ESD-2010: https://www.autometer.com/pub/media/man ... 0-1418.pdf

The example gives the test results for a battery that is rated at 600 CCA.
  • 610 (102%) is good
  • 450 (75%) is near end of life
  • 400 (67%) is bad
Like the other battery tester manufacturers, Auto Meter has selected 70% as the end-of-life indicator.
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Re: Car battery replacement interval advice

Post by ncbill »

sport wrote: Fri Nov 26, 2021 12:41 pm
tibbitts wrote: Fri Nov 26, 2021 12:37 pm
blaugranamd wrote: Fri Nov 26, 2021 9:39 am Truck batteries run near $300.
I didn't think conventional batteries for trucks cost more than for other vehicles, unless possibly you are multiplying by the number of batteries required. Regarding AGM, I'm not sure most people want to deal with installing an AGM battery in a vehicle that wasn't designed for at least the choice of using one.
Well, there are trucks and then there are TRUCKS. Large diesel trucks use a very large battery.
My 3/4 ton diesel pickup has two batteries.
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Re: Car battery replacement interval advice

Post by willthrill81 »

sport wrote: Sat Nov 27, 2021 11:03 am
willthrill81 wrote: Sat Nov 27, 2021 10:34 am Is grid corrosion mostly a result of the lead acid battery having been 'used up' (i.e., reached the expected end of its cycle life)?
The short answer is yes, although it is mileage, not cycle life. The explanation is that normal charging voltage has to be high enough to ensure a full charge. To prevent undercharging the battery, there is a small amount of overcharge. When a battery is charged, the active material in the positive plate is converted from lead sulfate,PbSO4, to lead peroxide, PbO2. When the battery is overcharged, some of the metallic lead in the positive grid is also converted into PbO2. This is why a battery can fail due to high mileage. The active material in the negative plate is converted from PbSO4 to metallic lead, so that grid is unaffected.

Evidence of this effect is shown in the warranty on batteries used in commercial trucks which operate almost 24/7. When I was in that business, the warranty was something like 90 days or 100K miles, whichever came first. :shock:
I see. It seems that more intelligent charging systems would lengthen the battery's lifespan, but I suppose that the cost to benefit ratio would be poor since the cost of replacing the battery isn't high.

It's crazy to think about trucks doing that kind of mileage in such a short period of time. We drove our RV 2,250 miles in 56 hours back in March, and I thought that was 'a long way to go and a short time to get there'.
“Good and ill have not changed since yesteryear; nor are they one thing among Elves and Dwarves and another among Men.” J.R.R. Tolkien, The Lord of the Rings
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Re: Car battery replacement interval advice

Post by sport »

willthrill81 wrote: Sat Nov 27, 2021 5:16 pm I see. It seems that more intelligent charging systems would lengthen the battery's lifespan, but I suppose that the cost to benefit ratio would be poor since the cost of replacing the battery isn't high.
Voltage regulators compensate for temperature by providing higher voltage when cold and lower voltage when warm. In the old days, like the 1930's and 1940's, when people drove long distances, they used their headlights during the day to use up some of that excess electricity to prolong their battery life. At least we have progressed beyond that.
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Re: Car battery replacement interval advice

Post by Electron »

sport - Thanks for a lot of very helpful information. Your post prompted me to review the construction of a lead-acid battery.

talzara - I agree on the 70% figure. There is very little that is precise when it comes to lead-acid batteries. In addition, there are different types of lead-acid batteries, different designs, and different battery chemistries. The battery materials and chemistries have also seen changes over time.

If anyone is interested in how a lead-acid battery fails, there is a lot of information available on the Internet. Here are two sites definitely worth reviewing.

https://batteryuniversity.com/article/b ... rnal-short

https://www.powerstream.com/1922/batter ... pter10.htm

Both sites indicate that material shed from the plates of a cell can result in a short circuit. However, the failure mode is more of a soft short that may take some time to discharge the cell.
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