Charging a MIld Hybrid Technology BMW

[VINCER0]

Originally Posted by MilehighM3

Bring up the vehicle info in the idrive and access the power flow. Here you'll be able to see the battery charge level which is indicated by the ratio of blue sectors to black/empty. You want 2-3 sectors to be blue, indicating 40-60% charge.

Put the vehicle in sport mode so you can see the tachometer and rev the engine to 3-4k until you see power flow being sent to the battery. Hold the RPMs at the point where the charging is operational until the desired charge level is achieved.

Originally Posted by VINCER0

Can you elaborate on this because the MHT in 2021+ M340i have the starter/alternator decouple from the motor during acceleration to improve emissions and performance...and recouples to charge the battery during braking, deceleration, and coasting. It also occasionally recouples during idle to temporarily charge for a few seconds so that the battery doesn't run down too low.

So this is interesting are you revving the engine in sport mode while driving or in neutral?

Originally Posted by MilehighM3

Park

Just as an update, I had my car in park and I revved the engine past 2-3k+ rpm and I saw that the car charged the battery to the 2nd blue bar only and not more than that.

As I mentioned before, I already knew that when the car is idle, it will automatically recouple the starter/alternator and charge the battery up to the 2nd blue bar only...so revving to 2-3k+ rpm in park just is the same result but done manually without waiting for the car's computer to manage it.

Were you able to charge the battery with your method to the 3rd bar? Full?

[johndoe1983]

Hi.

The tech told me this morning to charge the 12v battery with the hood open until it is full.

After that, disconnect the 48 volt connector at the battery (biggest connector)

Let the 4 amp trickle charger on for the rest of the winter. Hood open or close no difference since the 48v battery is disconnected.

One thing in noticed is that the defrost light is now flashing with the engine off. Light on the left side of the steering which illuminate the control for the exterior light is always on even if the doors are close. I started the car to see if it would start to find out that the climate control is red and nothing is working anymore.

I read that a guy had to reprogrammed twice his car at the dealer with such a problem.

The tech as never seen that before.

What a pain. 85,000$ car M440i 2021

[Teutonic]

Originally Posted by G22b58

Oh, so the X4 can now be charged with a 5A charger?
Earlier you wrote:
"I have a Noco 5 I think. What are you using?
I don’t get it. Both M340i and the X4 have the same clicking noise and no charging."

What, do you think, is the difference, did the X4 get a firmware update?
Is there a difference in how much charge there is in the 48V battery when you charge now compared to earlier?

I made a mistake on that one. The X4 is charging with the Noco 10. The M340i does not. I apologize.
Not sure what is the difference. However, my 2021 X4 is a 3.0i four-cylinder, while the 2021 M340i is a six-cylinder.

I can charge my X1 and X4 with Noco5 or Noco10 without issues.
My M340i can not be charged with these two.

[Teutonic]

A video from a guy who also tried two CTEK to charge his Mild Hybrid Technology vehicle was unsuccessful.
You can CC the video in English if you need.
I still have a problem connecting a 20 Ah charger to my battery. This will push a lot of current and charge the battery faster but that is detrimental to battery life. Plus, my annoyance is these chargers (Ctek 25 and Noco 25 are HUGE!)
Funny, this guy was told by his dealer to charge it with the bonnet closed....
I heard many people complaining and nobody knows the answer. The dealers are worse as the don't know not even as much as we do

BMW should be ashamed for staying quiet in this one!

[Teutonic]

Originally Posted by zazzau

Well I can understand your concern. The CTEK I use pushes max current at Bulk charging. In my case that takes just a few minutes before it moves to Absorption stage — where "the current is gradually reduced" (quoting technical doc.) This is where my charge spends the most time (few hours) before it gets fully charged.

This is probably how it works with dealer charger. You can perhaps contact CTEK for more tech details. The 25A rating just means it's the max it *can* push doesn't necessarily mean it's pushing at a constant 25A. Based on everything I've read it adjusts itself to what it believes the battery/system needs. You can of course contact CTEK. Hope this helps.

Deutronic chargers that BMW is using in the shops are professional grade units that can not be compared to what we use. Have a look at their settings. Don’t forget,those are shops chargers and are made tohelp the tech while working inclusding providing current for analyzing, repairs and other things without affecting your battery. Their inner software is not in your “regular Joe” unit.
Not lastly, that is a shop where they care about speed and time spent not your ideal charging pattern.

I guess that the fact that your battery gets charged in one hour instead of 4-5 (that a proper calculated charger) will provide the answer for you. Don’t forget that all these 4-5-6 Ah chargers are made like that for a scope.

By the rules, battery charging current should be 10% of the Ah rating of the battery.
Charging current for 100Ah Battery = 100 Ah x (10 ÷ 100) = 10Ah
That is the ideal Ah for charging such battery.

Why do you think BMW sells CTEK rebadged chargers that do not pass the limit?

[Teutonic]

Originally Posted by MilehighM3

Sorry for the late reply, been busy. I almost created and posted a YouTube link for this but here's a few pics to show the process of disconnecting the 48v battery to charge your 12v in storage.

The battery charging in idrive is found under driving info, power flow to charge your 48v battery.


I hope this helps. Let me know if you're successful and what the specs are again on your 12v charger.

Edit: mobile uploads jumbled the order of the pictures. ����*♂️ hopefully you get the idea/process. 3,1,2.4.5 for disconnecting the 48v system.

Originally Posted by JSaid

So the NOCO 25 got here and I gave it a shot. So first off, it works. After plugging it in, it began charging with no clicking noises! Only noticed one sound closer to full charge which I believe was a switch to charge the 48v. After the sound I noticed the battery level in idrive started going up.

One thing I did notice this time, if you plug the car in before all the interior lights go off, it starts clicking. If you wait ~5 minutes for everything to shut off and then begin charging, no clicking. This is different than what I experience with the mxs5, that one I couldn't get the clicking to stop no matter what

So, just an update from me.
I bought a Noco 25 to see if it works as claimed and how.

To add more to the confusion I an tell you that NOCO 25 DOES NOT WORK on my 2021 M340i MHT.

Noco 25 Connected to the 2021 M340i I have the same behaviour: charger is pushing charge, first LED blinks at 25%. Compared with the Noco 5 or Noco10, Noco 25 has a fan incorporated. The fan starts spinning at max, then the grinding noise in the central angine area and the following click (relay maybe) in the 48V battery area. The charging status does not evolve and continuously gets reseted like in the past.
POINTS:
- 12 V Battery is almost fully charged.
- The hood was open. Car locked, car unlocked, it doesn’t matter.
- Connected right away, or after 5 minutes after turn off, it doesn’t matter.
- the red hazard light and the left lights switch area are always lit
- in my case it does not switch to Li battery charge and shows nothing in the “energy flow” display like user JSaid mentioned.
- the “energy flow” does show however charging when engine is running and keep it over 1500-2000rpm.

To add more confusion to the problem, I connected Noco 5 and I get the same behaviour with gringing and clicking but no charging. So no change here.
But the Noco 10 got connected, and strange enough, it seems that the charging does occur this time (LEDs are evolving) but with grinding and clicking noises.
This time the battery was charged via trunk before, so almost full, so I wonder if the charging percentage has something to do with under the hood charging.


Noco 25 Connected to the 2021 X4 MHT I have the following:
Car charges but does not move to charge the Li battery. I might also have another problem with this car, as compared with the M340, the X4 even when engine runs, the “energy flow” shows nothing on my screen. My Lithium looks depleted, who knows what other susrprises I might get…

In the end, I am confused to max and start to believe that these cars are a pain to live with. still hope we can find the proper answer.

[G22b58]

To add a data point this is my observations:
I sat in my parked G22 MHEV, engine off, for an hour (preparing several routes for a road-trip) so I though I should try my new CTEK PRO25S in order not to discharge the batteries.

The observation I did not expect was: Both the 12V battery and the 48V battery was charging!

Configuration:
* The charger (can supply 25A) was connected under hood.
* Hood open (resting on the first latch).
* Car was "ON". Was using the navigation in iDrive.
* BimmerLink connected to OBD2 to monitor charge levels.

Starting point:
1) The hood open without charger connected, so the voltage in the 12V connector showed that the 48V system turned off (reduced from the normal 14.1V when the MHEV battery is used .
2) Connecting the charger in Normal (charging mode) and a current clamp meter showed 22A into the charging post.
BimmerLink showed charge levels: 48V=30% and 12V=58%. 12V battery voltage shown after a few minutes = 13.2V and 48V battery current= -2A.
(I had been using the car on 12V battery for a while, explaining the charge level.)
3) After about one hour BimmerLink repported charge levels: 48V=45% and 12V=62%. The current into the charging post under hood had reduced to 20A.

It seams possible that the 2A charging of the 48V battery corresponds to 15% (in the range of 65Wh). It could mean that about 8A of the input was used by the 48V system. It could mean that up to 4A (average) was used to charge the 12V battery.

[jwadd215]

Originally Posted by Teutonic

A video from a guy who also tried two CTEK to charge his Mild Hybrid Technology vehicle was unsuccessful.
You can CC the video in English if you need.
I still have a problem connecting a 20 Ah charger to my battery. This will push a lot of current and charge the battery faster but that is detrimental to battery life. Plus, my annoyance is these chargers (Ctek 25 and Noco 25 are HUGE!)
Funny, this guy was told by his dealer to charge it with the bonnet closed....
I heard many people complaining and nobody knows the answer. The dealers are worse as the don't know not even as much as we do

BMW should be ashamed for staying quiet in this one!

I've had this issue with my BMW Ctek charger and contacted my better of the two main dealers to be told it is definatley the correct charger and that it will takes hours to charge, maybe even overnight.

I have the bonnet open which disconnects the 48V battery from the circuit alledgedly but I was also told that If I close the bonnet it will charge both which is fine .

He said he would ask BMW UK the question as to why the noise occurs every 3 mins and all he got back was "tell the customer if there is any doubt to book the car into a dealer" it seems BMW ain't got a clue.

[jwadd215]

Originally Posted by jwadd215

I've had this issue with my BMW Ctek charger and contacted my better of the two main dealers to be told it is definatley the correct charger and that it will takes hours to charge, maybe even overnight.

I have the bonnet open which disconnects the 48V battery from the circuit alledgedly but I was also told that If I close the bonnet it will charge both which is fine .

He said he would ask BMW UK the question as to why the noise occurs every 3 mins and all he got back was "tell the customer if there is any doubt to book the car into a dealer" it seems BMW ain't got a clue.

Just tried a different charger with an analogue dial, it starts to charge, as soon as that motor noise starts the needle drops to zero and starts to come up again only for the processs to occur all over again.

[Teutonic]

Originally Posted by jwadd215

Just tried a different charger with an analogue dial, it starts to charge, as soon as that motor noise starts the needle drops to zero and starts to come up again only for the processs to occur all over again.

I know. And BMW is quiet like a mouse...
And NO ONE is able to describe why, how and what to do...

My techs are also baffled. Go figure...

[jwadd215]

Originally Posted by Teutonic

I know. And BMW is quiet like a mouse...
And NO ONE is able to describe why, how and what to do...

My techs are also baffled. Go figure...

Sounds well dodgy, I had the main dealer phone me back and they just advised me to bring the car in and the CTEK charger to test it all, however they could have worked this one out themselves with one of their MHEV cars as they sell the chargers. The dealer said my car may even have three batteries I think he may have been getting confused with the 330e PHEV when it's a 330d MHEV, eitherway it doesn't fill me with confidence.

[Teutonic]

Originally Posted by jwadd215

Sounds well dodgy, I had the main dealer phone me back and they just advised me to bring the car in and the CTEK charger to test it all, however they could have worked this one out themselves with one of their MHEV cars as they sell the chargers. The dealer said my car may even have three batteries I think he may have been getting confused with the 330e PHEV when it's a 330d MHEV, eitherway it doesn't fill me with confidence.

No you don't. You have two. An AGM in the trunk and theLi under the hood.
take the car with the charger. Fine. make sure you stay there with them so you can see their reactions. And ask for an official explanation. I am still waiting for mine.

[Teutonic]

So, getting back with an update.

Because of my M340i Mild Hybrid Technology, I bought, on top of my Noco 5, a Noco 10 and a Noco 25.

The car was fully charged on January 14, and I left it in the garage as I am out of the country for a few months.
One month later, I have asked my family to charge the M340i to make sure the battery is OK. The car is almost depleted as a critical battery message showed up on the dash.
Even after connecting the Noco 25, it does not charge.The grinding noise is back even with this charger, and nothing happens except the noise followed by a charger reset that starts again, and again, and again...
the single charging that works for me is disconnect the trunk battery cables and charge the battery. Otherwise nothing works.

All I can say is This is BS!

BMW is not providing any official input on it, and I strongly believe that is a design issue. BMW technicians know NOTHING about it; all they know is to connect their professional chargers and show me that "it appears to be working."

If I knew that this car is one that I need to bury my head in the trunk, disconnect the cables and charge via trunk every month, I would have never gotten it!

I don't care about my 10 HP plus from the POS mild hybrid technology car or the POS start-and-go annoyance that I need to turn off everytime for God's sake, all I want is a car that doesn't go dead on me because I am on vacation or gone for over a month. I've never owned a more agonising vehicle in my life.
My X1 loses charge, but very little in a month, my X4 is also ok, however, that one also has two batteries but it doesn't seem to be MHT so it's still ok.

And the most interesting, even here, on the forum, no tech comes in with a proper answer. No one knows anything!

Why BMW is not saying anything?

The MHT is just a pain that helps no one. Screw This!!!!

[johndoe1983]

You are right. Imagine m440i 2021 has been stored since oct 2022 and I do not plan to start it until 1st may 2023. My hair will surely turn white. What a crap. Mine also have the battery warning on the Idrive system and has a defrost flashing all the time. Also, it seem that the AC and Warmer control do not function any more. Will I buy another BMW in the summer time ?? NO NO NO never again.

[julioccuk]

Originally Posted by MilehighM3

Sorry for the late reply, been busy. I almost created and posted a YouTube link for this but here's a few pics to show the process of disconnecting the 48v battery to charge your 12v in storage.

The battery charging in idrive is found under driving info, power flow to charge your 48v battery.


I hope this helps. Let me know if you're successful and what the specs are again on your 12v charger.

Edit: mobile uploads jumbled the order of the pictures. 🤦🏻*♂️ hopefully you get the idea/process. 3,1,2.4.5 for disconnecting the 48v system.

I have the new X6 LCI which has the MHEV battery, I am trying to swap my paddle shifters so in order to do that I need to disconnect the trunk battery, but after doing so the horn is still going off so I can only assume I need to disconnect the front one too?

Would you be able to guide me here please?

Thanks
Julio

[vadim77]

Hi.
I have a similar problem with 6gt g32 b58 August 2020.

Same noise nearby 48v battery and charging is interrupting and starting again.
I am using semi prof. Charger made in Russia with manual set up of Voltage and Ampers needed for charging.
After some trials I have found that if voltage set up as max 13,9 V there is no clicking and interrupt of charging happens. Amperage I set up around 2 or 3 Amp.
I could not physically check until what volume I could charge 12v battery.
But its not enough to charge by this method.
I was charging with open hood inside motor compartment. Car is open.
I shall revert after some trials and studying TIS.

[G20801]

My agm battery went bad, it would drop to 5v over night. In order to charge it I had to remove the + and - cables off the battery in the trunk and charge it that way. If I used the post under the hood with the voltage that low it would freak out.

Once voltage was in the 12s I could then use a a normal charger on the post. I put a new battery in it last night so I will see if the car is causing the battery to go bad by something not going to sleep.

Note with voltage that low it wouldn't jump start, it would only freak out once I tried jumping it.

21 M340 MH.

[vadim77]

Originally Posted by G20801

My agm battery went bad, it would drop to 5v over night. In order to charge it I had to remove the + and - cables off the battery in the trunk and charge it that way. If I used the post under the hood with the voltage that low it would freak out.

Once voltage was in the 12s I could then use a a normal charger on the post. I put a new battery in it last night so I will see if the car is causing the battery to go bad by something not going to sleep.

Note with voltage that low it wouldn't jump start, it would only freak out once I tried jumping it.

21 M340 MH.

Nothing will happen if you charging from the hood side. The thing it's 5v is saying about some troubles with battery or car's net. Probably too long parking time without driving. Need to try to charge till 12v and then apply battery tester. If with tester under load the voltage will drop less than 9 or 8 volts so the battery is bad and better to change the battery.

[vadim77]

Finally I am charging with Ctek pro25s both batteries. As soon as 12v battery was mostly full after riding trip the charging was lasting about 15 min until stage 4 (as per Ctek Manufacturer Manual, ... voltage reached 14,4v and Ampers started to drop) and then after some short time and relay's click the 48v battery was charging around 15 min from 1 bar until 4 bars.

[Teutonic]

Interesting. the CTEK 25 works but Noco 25 does not. Maybe the Ctek provides that high Amper requirement and Noco does not?

Noco came up now with a Noco50 (50 Amp). I am wondering if someone tried that.