I also have a 1 year old AC Delco that is at 12.7 V with a CCA of 650.
Tracking an aging battery
- Thread starter Snagglefoot
- Start date
So hear we go. The battery is 5-1/2 years old. The battery test with the same tester used throughout the thread indicates 12.28 V and 719 CCA and still has the “weak” indicator lit. I’ll see how it does later in the fall. The car it’s in was used a lot this summer.
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forgot about this thread... I'll say it again I think you're going about this the wrong way. You should test a full charged battery with no load on it. 12.28v tells me its either not fully charged or there's a load on it (car's ECU, etc). if you don't want to take it out of the vehicle then leave the hood open overnight with a float charger on it. then remove the float charge the next morning and *without* opening the doors perform your test. I bet $$$ it measures 12.9V and 719cca and the tester will tell you its "OK", because apparently your tester is thinking low voltage means the battery is weak. regardless of SOC volts, 719cca is still plenty healthy the battery is not "weak" by any means.
Sorry, don’t agree. Here are my results on my 1-1/2 year old battery in my Burb. It will test at 12.7 volts no problem. Kira’s posting #4 gives a pretty good prediction of the drop in available battery voltage with the years. Charging an older battery may take it right up, but it will fade away with days, where as a newer battery will hold 12.7 V.
sorry now you're mixing apples & oranges.... how many days off charge was it when you measured 12.28? what was the load on the battery during that time?? and how does that compare to what you did last year?? these things matter and you didn't say. and how many days when your burb measured 12.7? and these are different vehicles --- with different parasitic loads. your testing methodology is all over the place. just because you post a pic showing 12.7 proves nothing.
I continue to maintain a battery that measures way above rated cca as you claim yours does is perfectly fine and capable of holding charge in the absence of parasitic loading. or perhaps your tester is faulty....
Get some small clamps, reverse them so their backsides hook inside, and can vastly increase the pressure that the original clamps provided with this tester can exert on the battery posts, and I bet once can achieve +/- 150CCA depending solely on the amount of clamp pressure on the battery clamps.
With so many influencing many variables, and little repeatability, I'd not put much faith in the specs spewed by any such tester, not without verification by other means.
It is an interesting data point, but uncontrolled, or ignored variables, are a female dog.
With so many influencing many variables, and little repeatability, I'd not put much faith in the specs spewed by any such tester, not without verification by other means.
It is an interesting data point, but uncontrolled, or ignored variables, are a female dog.
Thanks for the suggestions. This is just a low buck tester used on the battery at anywhere from 4 to 12 hours after shutdown and sometimes after a few days.
The end result pretty much follows the suggestions in posting # 4 from Kira. Older batteries tend to not be able to hold a 12.7 voltage. Newer batteries tend to be able to do that. At some point my 5-1/2 year old battery will have too low of a CCA to start my engine when the temperature drops to below 0 F which happens up here a lot. I would say that the Schumacher BT-175 might be reading too high but the battery is so far is starting the car. I may continue this, or just fold and buy a new battery. Perhaps others can quickly check their voltage after sitting 4 to 12 hrs and report back with the voltage reading and battery age. It is important not to have any lights on, but the usual parasitic drain is “ in the noise”. If any one else wants to do a more scientific set of tests, please do.
The end result pretty much follows the suggestions in posting # 4 from Kira. Older batteries tend to not be able to hold a 12.7 voltage. Newer batteries tend to be able to do that. At some point my 5-1/2 year old battery will have too low of a CCA to start my engine when the temperature drops to below 0 F which happens up here a lot. I would say that the Schumacher BT-175 might be reading too high but the battery is so far is starting the car. I may continue this, or just fold and buy a new battery. Perhaps others can quickly check their voltage after sitting 4 to 12 hrs and report back with the voltage reading and battery age. It is important not to have any lights on, but the usual parasitic drain is “ in the noise”. If any one else wants to do a more scientific set of tests, please do.
what you need to do is test the fully charged battery after sitting overnight with no load (eg remove one of the cables, or remove it from the vehicle) *OR* test it when the vehicle has settled to steady state parasitic draw which for most vehicles is ~30mins after the car was last *touched*... and by touched I mean doors opened/closed, doors unlocked, key fob nearby, etc... so, you can't go out to the garage, open the car door, pull the hood latch, and then go measure the battery and expect a meaningful result --- because the ECU will be doing all sorts of stuff, drawing amps, and pulling down the battery voltage. and about 3hrs after you drive it most cars go through an EVAP purge which also drains the battery.... so, hence my earlier suggestion -------> open the hood, put it on a charger, keep the key fob away, remove the charger when fully charged, then let it sit overnight with open hood, then without "touching" anything (eg don't open the doors) test the battery.
if after all that you measure 12.28V the next morning then I agree your battery is toast, or you have abnormally high parasitic draw (which you should then confirm by measuring it). I've just never seen a battery measure high cca like yours and not be able to hold a charge under normal conditions. either the measurement is off or the conditions are not normal.
if after all that you measure 12.28V the next morning then I agree your battery is toast, or you have abnormally high parasitic draw (which you should then confirm by measuring it). I've just never seen a battery measure high cca like yours and not be able to hold a charge under normal conditions. either the measurement is off or the conditions are not normal.
I decided to charge up the battery on Friday and let the car sit over the weekend until Monday morning with just the parasitic drain.
Prior to charge: 12.24 V
Fully charged: 12.67 V
24 hrs 12.33 V
48 hrs 12.24 V
72 hrs 12.22 V
From a check earlier, the parasitic draw after settling down is 34 mA.
I think I’ll keep it in use this winter and check again in the spring, unless I get a poor start when it cools down. I usually plug in if the temp goes to 0 F.
hmm. it'll probably last the winter, but I wouldn't trust that cca measurement. if you wanted another data point you could get the $15 100A load tester from HF https://www.harborfreight.com/100-amp-612v-battery-load-tester-61747.html
you can't fool a real load test. either it holds voltage or it doesn't. I use both types of testers, they each have their purpose.
@Snagglefoot
I appreciate these types of real world long-term tests.
It's obvious to me you've settled on a methodology that's aware of and has reduced the variables.
Could you be more scientific with a $600 battery cycler? Sure... But I don't see anyone here with one posting a repeatable test for over 5 years.
Keep up the good work!
I appreciate these types of real world long-term tests.
It's obvious to me you've settled on a methodology that's aware of and has reduced the variables.
Could you be more scientific with a $600 battery cycler? Sure... But I don't see anyone here with one posting a repeatable test for over 5 years.
Keep up the good work!
I did as start at 1 deg F with the car outside sitting in the cold. The voltage was 11.9 V. The start was fine. Onwards towards the winter.
I did a start after the car sat through the recent cold spell with the lowest temp being -22 F.The battery tester showed 11.88 V and 535 CCA. It had warmed up and was just below freezing. The start was fine.
Just an update on the AC Delco. It was unable to start the vehicle ( 2008 Suburban) if a radio was kept on for 10 minutes without the engine running. The voltage would go down to 11.6 volts and it couldn’t start the vehicle. It got it replaced on warranty at 2 years of use. I got another AC Delco 770 CCA 42 month free replacement battery.
We are enjoying temps just around freezing and I’m getting a voltage just over 12 V on the Ever Start. As long as it does that I’ll keep going.
The last time was 2-1/2 months ago, so no, I’m not using any charge based maintenance program. The car gets a 40 mile run once a week. I probably should top it up, but I’m trying to see how long it last without any extra charging.
Interesting. I wonder what would happen if your car did not start on the first try, even though the starter motor was operating normally. Would the battery have enough capacity left to crank the engine a second or third time?
I did a start this morning at - 8 F, but it was plugged in overnight. It was a very smooth start.
I believe it would. In fact, sometimes I need to make a second attempt. I replaced the IAC with a new Motorcraft one but no improvement.
