Battery not charging above 12.2v

[edsonreds]

Hi. I have a 2011 E92 M3 and the battery was replaced by the dealership about 2yrs ago. In the last months the battery started to NOT hold above 12.2 volts. I purschased the CTEK 40206 MXS 5.0 which has a recond AGM mode. I have been using this mode for 1 week and the battery doesnt go above 12.2. When I start the car and the alternator kicks in, voltage surges to 14.3v. After turning of the car, the battery voltage drops to 12.8 and continues to drop in 4 to 8 hours up until reaching 12.2v.

[jazzy1999]

Check Alternator ??

[edsonreds]

Originally Posted by jazzy1999

Check Alternator ??

Please, explain. I know that the alternator kicks in correctly because the voltage when the car is running surges to 14.3, which is normal according to some posts. After I turn off the car, battery voltage start to drop.

I only make some miles from point A to B, about 3hrs each day commuting.

I have no engine lights or error codes.

[randrews15]

Could be a draw on the battery with the electrical system or you got a bad reconditioned battery. Just my two cents..

[edsonreds]

Originally Posted by randrews15

Could be a draw on the battery with the electrical system or you got a bad reconditioned battery. Just my two cents..

Thanks! How could I find out? Taking suggestions. Strange thing is that my ctek charger doesnt climb to the level 8 (max recond mode), even after leaving it for 48hrs.

Worst case I thought I ought to replace the battery, which sucks given that it only is 2yrs old.

Now I fear some electrical failure.

[randrews15]

You would need to load test the battery before replacing it. It's not uncommon for a battery to discharge as it sits but the rate it does is the issue. I'm thinking that it's probably the battery and may need to steer away from a reconditioned one. Tracking down a draw is a little more tricky as you would have to try to narrow down which system is draining the battery. Like I said, I'd look at the battery first and see where it leads you down the rabbit hole.

[SkiFly01]

I would charge the battery and watch for voltage drain with it disconnected from the car in case you do have a higher draw when not running. It is possible to have a cell that has a crystal which formed a short. A crystal could form if charged in extreme low temperatures. Isolating it to test is a simple way to verify if it's the battery at fault or something in the vehicle.

[M43S7RO]

Take it to local auto parts store to be tested before you start diagnosing for crystals.

[Throatpunch]

Do you have edc? Those can drain alot. Check if start button stays lit up long after u exit the vehicle

[TX]

I had a bad EDC module which was not shutting off and would drain my battery, but if that were the case he should have a dash alarm of excessive battery discharge the next time he starts the car. It keeps track and will give you a heads up. It took the dealer to find the cause of the discharge however.
I'd lean towards a failing battery as you say this is a reconditioned battery.

[mapster37]

does the car have an acutal starting issue or are you just monitoring battery voltage??

[edsonreds]

Originally Posted by mapster37

does the car have an acutal starting issue or are you just monitoring battery voltage??

Car doesnt want to start at first crank.

[TX]

Originally Posted by edsonreds

Car doesnt want to start at first crank.

You say the battery rests around 12.2v, which isn't terrible. AGMs are a little lower resting. Put a DC volt meter on the battery and have someone else crank the car. While it cranks, If the voltage does a major dip say below 10v. It will be quick and you know right off you have a bad battery, usually dead cell. (not sure of the term in AGMs) as it is only holding a surface charge. I've seen engines start around 10v. I had to look at two cars this week both had bad batteries they dropped to around 7-9v one started one wouldn't. Anyway that's a simple load test for you.

This is the battery I put in my car. I'm past 4 years so I'm thinking of replacing it again. It's been good in summer heat in Florida which isn't half bad. I'm not affiliated in any way just posting what I've used. It's a direct drop in replacement. There are several tools that will register a new battery for you for free that you can use also. You'll want to do that to make sure the car is charging the battery properly. As the battery ages the car adjusts the charge cycle on the battery so you need to tell it you have a new battery.

https://www.pepboys.com/bosch-premiu...product/838838

Hope this helps some,
Cheers,

[Helmsman]

OP, did you keep the Ctek outside while charging (for example between windsheild and hood), or did you have to unlock the car to check it? Its only 5A and soon as you unlock/start electronics it drains quite a bit of power and force the voltage down.
12.2V sounds a bit low for a fresh battery but it certainly goes well below the unloaded 12.8V isch level.

Cheers

[edsonreds]

Originally Posted by TX

You say the battery rests around 12.2v, which isn't terrible. AGMs are a little lower resting. Put a DC volt meter on the battery and have someone else crank the car. While it cranks, If the voltage does a major dip say below 10v. It will be quick and you know right off you have a bad battery, usually dead cell. (not sure of the term in AGMs) as it is only holding a surface charge. I've seen engines start around 10v. I had to look at two cars this week both had bad batteries they dropped to around 7-9v one started one wouldn't. Anyway that's a simple load test for you.

This is the battery I put in my car. I'm past 4 years so I'm thinking of replacing it again. It's been good in summer heat in Florida which isn't half bad. I'm not affiliated in any way just posting what I've used. It's a direct drop in replacement. There are several tools that will register a new battery for you for free that you can use also. You'll want to do that to make sure the car is charging the battery properly. As the battery ages the car adjusts the charge cycle on the battery so you need to tell it you have a new battery.

https://www.pepboys.com/bosch-premiu...product/838838

Hope this helps some,
Cheers,

Thank TX for your thoughts. There is an option in the central dash where I can monitor the voltage before, during and after cranking.

As you say, voltage drops. During cranking it drops bellow 10v rapidly because the engine attempts to start. In that moment RPM indicator goes above 1k rpms but rapidly drops, in some cases stalling the engine, on other RPMs surge again as the alternator kicks in and voltage goes up to 14.3v

It is not a recond battery, I must mention that I tried the ctek recond mode but I dont seem to get a voltage above 12.2v with this charger.

After driving the car for one hour, voltage gets to 12.8 but it levels to 12.2v again.

[edsonreds]

Originally Posted by Helmsman

OP, did you keep the Ctek outside while charging (for example between windsheild and hood), or did you have to unlock the car to check it? Its only 5A and soon as you unlock/start electronics it drains quite a bit of power and force the voltage down.
12.2V sounds a bit low for a fresh battery but it certainly goes well below the unloaded 12.8V isch level.

Cheers

I get you.

I have the ctek charger outside the car on the floor and left it for 48hrs in recond mode for AGM car batteries.

This weekend I tried this: left the ctek charger on, enter into the car, turned off every electrical switch (lights, AC, radio) but entered in the CIC option to monitor battery voltage. Before cracking: 12.2v (after 48hrs of ctek magic), during the cranking voltage drops bellow 10v, after it stabilizes alternator kicks in and voltage goes to 14.3v

[mapster37]

if it drops to 10v while cranking, replace the battery.

[edsonreds]

Originally Posted by mapster37

if it drops to 10v while cranking, replace the battery.

Yeah, I fear that. Look, I filmed it. The video shows voltage drop, this time not bellow 10 and not stalling, but there is some struggle at start up and voltage dropping to 10.6v; and erratic RPM.

https://drive.google.com/file/d/1m32...w?usp=drivesdk

[Helmsman]

Originally Posted by mapster37

if it drops to 10v while cranking, replace the battery.

Below 10v is low, yes sounds like new battery. Strange after 2y only, mine was fine after 5y, but hey gotta pay....

[edsonreds]

Originally Posted by Helmsman

Below 10v is low, yes sounds like new battery. Strange after 2y only, mine was fine after 5y, but hey gotta pay....

Yeah, I am afraid so. Lets pay! But not to the stealership! Do you have any suggestion on the battery specs?

From factory the E92 came with a 80ah with 640 cca, by exide, but it has been discontinued.

The stealership replaced mine with a 80ah with 800 cca. Should I go the same? I heard some guys replacing with a 90ah battery.

My current faulty battery code is 61217555719.

[oolas3]

Originally Posted by edsonreds

Yeah, I am afraid so. Lets pay! But not to the stealership! Do you have any suggestion on the battery specs?

From factory the E92 came with a 80ah with 640 cca, by exide, but it has been discontinued.

The stealership replaced mine with a 80ah with 800 cca. Should I go the same? I heard some guys replacing with a 90ah battery.

My current faulty battery code is 61217555719.

Any H8 AGM battery should work. I have the Advanced Auto Parts H8 AutoCraft AGM Battery that cost $150 on sale. It will need to be registered but any indy shop could do that.

https://www.m3post.com/forums/showthread.php?t=1281281

[Helmsman]

Originally Posted by edsonreds

Yeah, I am afraid so. Lets pay! But not to the stealership! Do you have any suggestion on the battery specs?

From factory the E92 came with a 80ah with 640 cca, by exide, but it has been discontinued.

The stealership replaced mine with a 80ah with 800 cca. Should I go the same? I heard some guys replacing with a 90ah battery.

My current faulty battery code is 61217555719.

Like Oolas above says anything will do but I'd go with something close to OEM spec (believe my E90 is 90Ah/900CCA but maybe due to more options etc). Should you differ from the spec, you need to "code" the car i order for the battery mgmt to keep track of consumption/charging. Regardless of OEM spec or not you need to "register" to let the system know you have a new battery. Both coding and registering should be possible to do with for example Carly.

Cheers