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I would think old batteries don’t charge to their original/full capacity anymore even when fully charged.
 
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I would think old batteries don’t charge to their original/full capacity anymore even when fully charged.
Probably normal for the age. You dont know how far it can charge. Charge it, flip the lights on a second, check it after an hour. Change cca to 850 EN. Be sure to test at the battery, not at the jump posts and see what you get. Dont check after “ maintaining” but just after its charged. IR meant internal resistance. MR I think is the same.
@grim good call. I set the rating to 850 en as suggested. Here are the latest results. The battery still states good but needs charging after just coming off charger so my take is it won’t take a full charge anymore. It now shows 12.40volts and 583 en. SOH is 71%and charge came up to 75% with the Ctek green light lit. Just read that the 12.41 volts is in range can’t find what the minimum SOH is for an AGM so I think the battery may still be good. Resistance also dropped?

Your thoughts.
239374
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Yes, imo, I would get a new battery. The internal resistance is high which to me means its sulphated permanently and only going to get worse. You can't get it fully charged. But hey, I wouldn't complain its 6 years old! I think that very good. :)
 

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Discussion Starter · #124 ·
@grim good call. I set the rating to 850 en as suggested. Here are the latest results. The battery still states good but needs charging after just coming off charger so my take is it won’t take a full charge anymore. It now shows 12.40volts and 583 en. SOH is 71%and charge came up to 75% with the Ctek green light lit. Just read that the 12.41 volts is in range can’t find what the minimum SOH is for an AGM so I think the battery may still be good. Resistance also dropped?

Your thoughts.
Are you testing at the battery itself?

Usually SOH = measured EN A (or CCA) divided by spec.
You can call Autel & ask then what the % EN A must be to qualify as "Good." Does the manual tell you if it says anything other than; Good, Recharge/Good or Bad?

If you are testing at the battery terminals it is surprising that you only read 12.4 V, after a full charge.

When I charge my batteries & remove from charger after CTEK step 7/green light...I immediately attach a multimeter & get a reading (I know there is surface charge) I typically get 12.7 V or higher up to 13.00 V depending on temperature & which car battery. I remove MM & connect my Solar tester & it always reads a bit lower. But only a few volts.

Do you have another car that you can fully charge & immediately use your Autel tester on?

Do you have a multimeter? They are cheap & very useful Test AA, AAA, 3V coin & 9V batteries for example.

It will be useful to know for example that your multimeter also reads ~ 12.4 V after a full CTEK charge & that if you use your Autel tester on a car with a newer battery, it reads 12.7+ & just says "Good" Not Good/Recharge.

The easiest thing to do is buy a multimeter, fully charge battery, check & see if you can charge up to 12.7+V.

I would be concerned with only 70% SOH (If true) & failure to fully charge.

Do you carry a battery jump starter with you? For the Macan, I recommend JNC. Allows you to be self reliant rather than asking strangers to give you a jump start or call & wait for AAA or your car insurance roadside assistance, which is usually much less $.
 

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Are you testing at the battery itself?

Usually SOH = measured EN A (or CCA) divided by spec.
You can call Autel & ask then what the % EN A must be to qualify as "Good." Does the manual tell you if it says anything other than; Good, Recharge/Good or Bad?

If you are testing at the battery terminals it is surprising that you only read 12.4 V, after a full charge.

When I charge my batteries & remove from charger after CTEK step 7/green light...I immediately attach a multimeter & get a reading (I know there is surface charge) I typically get 12.7 V or higher up to 13.00 V depending on temperature & which car battery. I remove MM & connect my Solar tester & it always reads a bit lower. But only a few volts.

Do you have another car that you can fully charge & immediately use your Autel tester on?

Do you have a multimeter? They are cheap & very useful Test AA, AAA, 3V coin & 9V batteries for example.

It will be useful to know for example that your multimeter also reads ~ 12.4 V after a full CTEK charge & that if you use your Autel tester on a car with a newer battery, it reads 12.7+ & just says "Good" Not Good/Recharge.

The easiest thing to do is buy a multimeter, fully charge battery, check & see if you can charge up to 12.7+V.

I would be concerned with only 70% SOH (If true) & failure to fully charge.

Do you carry a battery jump starter with you? For the Macan, I recommend JNC. Allows you to be self reliant rather than asking strangers to give you a jump start or call & wait for AAA or your car insurance roadside assistance, which is usually much less $.
@iconoclast Regarding charge status if you take a reading after immediately disconnecting the charger you might be reading surface charge. This unit would not allow a voltage reading until you ran the headlights for some time to get an accurate voltage reading eliminating the surface reading. According to some information on the web an older battery will not accept a full charge and the 12.4 volts is in the good range?

I do have my wife’s car the SQ5 which is a 2018 which I’m going to put on the Ctek charger and get a comparison between old and newer. At this time I’m still making a decision but will most likely replace as its 6 years old and that’s what I got out of my wife’s last BMW, AGM battery. That one failed without warning which is what I think these AGM‘s will do. Instead of carrying a jump starter that money can go towards replacing the battery.

I do have an older volt/ ohm meter and last time I checked the charge after disconnecting the charger I got the higher reading you are referring to. I believe I was reading surface charge at that time.

@grim do you have an idea what the resistance should read? I cannot find what is good or bad regarding this and the instructions with the tester does not give guidelines. I will try to contact the manufacturer to see if they have better test standard guidelines.

Thx for the response from both I’ll let you know if I find out anything different but grim’s right got 6 years, time to pop for a new battery.
 

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@grim do you have an idea what the resistance should read? I cannot find what is good or bad regarding this and the instructions with the tester does not give guidelines. I will try to contact the manufacturer to see if they have better test standard guidelines.
First, watch this. He explains why you need to register the battery. Just like we thought, the car will think its the old battery and eventually cook it


Then watch this from Varta. They talk about how loose cables can cause different readings. Its subtitled


This is the original varta article. Read the part about how the SOH is not a simple equation but a combination of CCA think EN, CA, and Amp hours. No formula is given.


Here is the reference in that article, no real answer on the formula but the good or bad decision is a combination of things


I can find no clear answer on what IR should be other than the results I've tested and when the IR goes up, the SOH goes down.
 

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Well, with the available $60 BT app tool I would say go ahead and register the battery. An indy shop charges about $50 to do it.

I just ordered the BT app tool from Amazon for $61.
 

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I just got a voltmeter from Amazon and tested my Macan's OEM battery. It is 6 years 1 month old with 42k miles. The voltage tested directly at the battery terminals is 12.02 volts with car off.

Googled for good car battery voltage @12.4-12.9 volts. Guess it's time to get a new battery.
 
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Discussion Starter · #129 ·
That seems to be < 50% charged.

Did you fully charge the battery, with your CTEK (or other maintainer) & then test the voltage with your multimeter?

Yes, I know it will have surface change.

Are you having any low battery symptoms?
Slow crank?

Do you carry a jump starter with you daily?
 

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I used a battery tender to fully charge the battery (light turned green on the tender), and then measured the battery voltage again at the terminals. It was 12.24v.

Google results suggest 12.2v means 50% charged. So my OEM battery can only be charged to 50% max now. Guess it is bad? Another method to test the battery is to do a crank test, i.e., measure the battery voltage while cranking the engine. If the voltage stays above 9.6v the battery is still good. I may do that test as well.
 

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I used a battery tender to fully charge the battery (light turned green on the tender), and then measured the battery voltage again at the terminals. It was 12.24v.

Google results suggest 12.2v means 50% charged. So my OEM battery can only be charged to 50% max now. Guess it is bad? Another method to test the battery is to do a crank test, i.e., measure the battery voltage while cranking the engine. If the voltage stays above 9.6v the battery is still good. I may do that test as well.

I tested my battery again after it sat overnight. The voltage dropped to 12v from 12.2v after fully charged. I then did the engine cranking test while measuring the battery voltage. Car started right up and the battery voltage dropped to 10.4v during engine cranking. That means the battery still has very good cranking amp/capacity.

Now I am a bit baffled. The battery voltage seems too low even after fully charged @12.2v but it still outputs good cranking power. So voltage is not the only measurement for battery health/capacity?
 

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There have been several discussions in this very thread about different types of ways to measure battery health.

In the almost 1000 posts in a thread supposedly about replacing and registering a battery almost every "related" topic has been covered (I'm
waiting for the discussion about maintaining a money tree in one's back yard :oops: ).


RECOMMENDATION: Look through the thread and locate these discussions.


Good luck!
I read the posts when they were posted but there are too many of them, so I don’t remember everything I read. Also, I am not an expert or even knowledgeable about car battery.

Can someone who is more knowledgeable tell me if I should replace my battery now? It seems to perform perfectly fine.
 
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I read the posts when they were posted but there are too many of them, so I don’t remember everything I read. Also, I am not an expert or even knowledgeable about car battery.

Can someone who is more knowledgeable tell me if I should replace my battery now? It seems to perform perfectly fine.
If it's performing fine, you can probably leave it alone. If you're not sure, take it to an auto parts store for testing - most big national chains will do it for free and a basic test can be done with the battery in the car. Charge it fully before you go.

There are only a small number of car battery manufacturers and they're all about the same in terms of reliability and specs, so pick the cheapest and best warranty (or the best logo, etc.). For example, Johnson Controls/Clarios is the OEM for Varta, Interstate, Diehard, and many others.
 
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Thanks everyone!

I plan to have my battery tested next week at the Interstate battery store. They use a special test method. Hopefully it’s more accurate.
 

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Discussion Starter · #135 ·
I read the posts when they were posted but there are too many of them, so I don’t remember everything I read. Also, I am not an expert or even knowledgeable about car battery.

Can someone who is more knowledgeable tell me if I should replace my battery now? It seems to perform perfectly fine.
https://www.macanforum.com/threads/battery-soh.174737/
I suspect your battery is bad but, I would want to do a proper test. Either an old fashioned load test or better, a State of Health (SOH) test from battery capacitance/resistance tester.
The auto shop you're taking it to probably has that tester.

If you carry a battery jump starter with you you have more time. If not, you may end up stranded till you can get roadside assistance or a jump start.

BTW, have you verified the your CTEK is working correctly on a different car? It will charge a different battery to 12.6+ V?
 
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I do have a portable Li-ion battery jump starter in my Macan.
 

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https://www.macanforum.com/threads/battery-soh.174737/
I suspect your battery is bad but, I would want to do a proper test. Either an old fashioned load test or better, a State of Health (SOH) test from battery capacitance/resistance tester.
The auto shop you're taking it to probably has that tester.

If you carry a battery jump starter with you you have more time. If not, you may end up stranded till you can get roadside assistance or a jump start.

BTW, have you verified the your CTEK is working correctly on a different car? It will charge a different battery to 12.6+ V?
The car's own computer should track SOH and you can report on it with a variety of diagnostic tools. Certainly PIWIS can do it. I know my Foxwell NT510 can do it on BMWs. Haven't tried this with my NT510 or iCarsoft POR v2.0 yet on the Macan though.

Edit: actually, I need to go back and check. It might be SOC on the Foxwell.
 

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Discussion Starter · #139 ·
The car's own computer should track SOH and you can report on it with a variety of diagnostic tools. Certainly PIWIS can do it. I know my Foxwell NT510 can do it on BMWs. Haven't tried this with my NT510 or iCarsoft POR v2.0 yet on the Macan though.

Edit: actually, I need to go back and check. It might be SOC on the Foxwell.
How exactly does the Porsche Macan's "own computer" track battery S.O.H?
 

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How exactly does the Porsche Macan's "own computer" track battery S.O.H?
Take a look at this from PIWIS (start at about 13 min). Not 100% sure it's SOH (vs SOC or something else), but clearly the computer keeps tracking of battery health in some way and this is obviously what the dealer is using to evaluate your battery. I suspect 3rd party tools can access this info as well, but haven't tried myself.
(this is a Cayenne, but it's most likely the same for all recent models)
 
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