[smomin23]

SmartSaves thank you for the detailed write up!

One question: if you have the automatic iDrive shut off enabled (turn off when vehicle door is opened), do you still need to set idle state manually?

[SmartSaves]

Originally Posted by smomin23

SmartSaves thank you for the detailed write up!

One question: if you have the automatic iDrive shut off enabled (turn off when vehicle door is opened), do you still need to set idle state manually?

In theory we shouldn't need to initiate idle state manually, but there could be many reasons iDrive might not shut off by itself even if we have the settings enabled due to software bugs, background tasks, telematics, accessories, etc.

[smomin23]

Originally Posted by SmartSaves

In theory we shouldn't need to initiate idle state manually, but there could be many reasons iDrive might not shut off by itself even if we have the settings enabled due to software bugs, background tasks, telematics, accessories, etc.

Makes sense. This is a step to ensure success essentially by removing variables.

I'll probably be charging over the weekend for the first time. Hope all goes well!

[SmartSaves]

Originally Posted by smomin23

Makes sense. This is a step to ensure success essentially by removing variables.

I'll probably be charging over the weekend for the first time. Hope all goes well!

If you want to be extra careful then use Digital Key Card to do the steps. It removes another variable (comfort access proximity sensors used by key fobs).

[GREENPUS]

Originally Posted by ChiefOne

Folks - question on using a voltmeter. I was planning to buy one, but unsure as to where I would connect it, in the terminals under the hood or to the main battery in the back? Appreciate your input.

This is the one, I was planning to get -
MOTOPOWER MP0514D 12V Digital Battery Tester Voltmeter and Charging System

Link:
https://www.amazon.com/MOTOPOWER-MP0...5CK6WDWNC8MZQY

Did you ever test the voltages at the terminals under the bonnet and directly on the 12v AGM battery? Just curious what your readings were.
ChiefOne

[youngbr]

I have a X5 45e, just plugged my CTEK MXS 10 charger to the terminals under the hood and it charged and the indicator lights moved through the stages systematically, no issue. Took around 5 hours. Car unlocked and hood up during the charge.

[GREENPUS]

SmartSaves SIB 61 01 21 dated 3-2021. This version replaces January 2021 version. Needless to say, I'm done using trickle/smart chargers on my mild hybrid
https://g05.bimmerpost.com/forums/sh....php?t=1827253

[Notleks24]

This maybe a stupid question. But why do these premium car batteries need to be charged? Why doesn't running the car do this.

I'm on the verge of purchasing one of these CTEK as apparently my battery is low at 12.1volts. Software updates won't install and start/stop isn't working.

Is this likely to resolve the issue? Or simply cause more issues?

2020 G20 320i

Thanks in advance

[jad03060]

TO gain a slight mpg increase, BMW has implemented a clutch on the alternator so that it's not a drag on the motor all of the time. When you're coasting or decelerating, it engages the clutch to use some of that momentum to then run the alternator. It will engage it while cruising, but not that often. Especially in the winter, where your fans, heated surfaces, lights, etc. are likely on more, and it's harder to start the vehicle when it's cold, if your trips aren't long enough, your battery may never get recharged fully. Start/stop means it is using a fair amount of energy to keep things running with no opportunity to charge when the engine is stopped...so, for some people, based on where, when, and how far they drive, the battery may not get fully recharged, and get depleted a bit each time you drive it. A battery maintainer can help keep it topped off which can extend the life of the battery considerably.

[bxz]

I found Greenpus' post first after seeing the rear defrost flashing together with dead AC. Today after a week with the X5 left at the dealer, I got it back with the service report.

Here's the story, I bought this car for my Dad in May 2021. He rarely drove, so one day the alarm "replace battery" came on although starting the car didn't seem any problem. I took it out for a spin, thought the alarm would go away after putting on 100 miles. Well, it wouldn't, so I drove for another hour or so, the second day I checked, still there. Went to the dealer and they had to replace with a new battery, the service rep told me to get a battery tender, so I found this CTEK MXS 5.0, which BMW also use with its name on it. I thought now it must have no issue parking there after all. Wrong!, I put the charge on, it took a couple of days for all the 7 lights on, so I thought the charge was done and I could just leave it plugged in. Had no idea when the rear defrost light was flashing til my Dad took the car out for groceries, and the AC was DEAD, although the car status was all OK! no error message, no alarm, nothing. So it went to the dealer again.

It ended with replacing the control unit for the AC and the AC display panel. They also replaced the emergency battery for the telematic control unit under the headlining.

I have no idea why they are making the cars so complicated that a battery charger will rendered the AC unit dead, who knows maybe next time the car won't even turn on.

So much for the high tech, my 2001 ISUZU still runs trouble free with no major service, only thing I did was oil change.

Originally Posted by GREENPUS

SmartSaves SIB 61 01 21 dated 3-2021. This version replaces January 2021 version. Needless to say, I'm done using trickle/smart chargers on my mild hybrid
https://g05.bimmerpost.com/forums/sh....php?t=1827253

[doyall]

Originally Posted by Notleks24

This maybe a stupid question. But why do these premium car batteries need to be charged? Why doesn't running the car do this.
...

Engine operation will charge the starting battery IF the vehicle engine is run long enough. If all you do is short trips the starting battery may never get brought up to full charge. (Not sure how mild hybrids work.) And if the vehicle is not operated for weeks (or especially months) at a time, the various functions of the vehicle requiring continuous battery power will deplete it. Severe temperature extremes will also accelerate self discharge.

I have several automobiles that I do not drive enough to keep a good charge on the battery so I try to put charger on them every week or so.

If your vehicle has an AGM starting battery make sure you get the correct charger. Chargers for FLA batteries do not sufficiently charge AGM's due the difference in charging profiles.

[TurtleBoy]

Originally Posted by doyall

Engine operation will charge the starting battery IF the vehicle engine is run long enough. If all you do is short trips the starting battery may never get brought up to full charge. (Not sure how mild hybrids work.) And if the vehicle is not operated for weeks (or especially months) at a time, the various functions of the vehicle requiring continuous battery power will deplete it. Severe temperature extremes will also accelerate self discharge.

I have several automobiles that I do not drive enough to keep a good charge on the battery so I try to put charger on them every week or so.

If your vehicle has an AGM starting battery make sure you get the correct charger. Chargers for FLA batteries do not sufficiently charge AGM's due the difference in charging profiles.

For quite a few years now BMW has been using Brake Energy Regeneration for charging the batteries, including on the mild hybrids. The batteries are not charged during driving/accelerating since the alternator is disconnected from the drivetrain at that point. When you coast, decelerate or brake then the clutch is engaged and the alternator starts charging.

Here is a little article on it. https://www.autobytel.com/car-owners...ration-123423/

[jad03060]

It may be that a long drive on flat surfaces at a steady speed may not provide many opportunities for the system to charge the battery, and the logic may let it discharge a bit before it decides it needs to charge it anyways. So, it likely depends on your mix of driving. Note that short trips, especially in the winter, can be hell on any battery, even if the alternator is not on a clutch!

On my 535GT, after needing two new batteries in the first three years, I started to put it on a Bosch battery tender most of the time. That third battery lasted 7 more years without issues before I sold it to buy the X5. It had the same clutch system on it, but the logic may not have been as evolved given the age of it.

[doyall]

Originally Posted by TurtleBoy

For quite a few years now BMW has been using Brake Energy Regeneration for charging the batteries, including on the mild hybrids. The batteries are not charged during driving/accelerating since the alternator is disconnected from the drivetrain at that point. When you coast, decelerate or brake then the clutch is engaged and the alternator starts charging.

Here is a little article on it. https://www.autobytel.com/car-owners...ration-123423/

Interesting. Thanks for the link. Learning a lot. But that may be even more of a reason to occasionally charge it.

[jad03060]

There are driving situations where the charging technique may not achieve a full charge on the battery. Stack multiple trips consecutively, and it can become critical. No battery likes to be deep discharged although an AGM is better at it than the older flooded cell type. Throw in wintertime, heavy heating loads, more lighting loads, harder starting, and it can become more important then versus the summertime, when a battery has more capacity because of the ambient temperature.

[TurtleBoy]

I don't know what the bottom threshold is but the system will charge the battery when needed even if you are accelerating.

[TurtleBoy]

Looks like the point at which charging occurs is when it goes down to 60% state of charge. They are having a similar discussion in the G20 forum. Here is what HighlandPete posted:





https://g20.bimmerpost.com/forums/sh...9&postcount=24

[jad03060]

I don't know the size of the alternator on the 40i or 50i, but on an older BMW I had with this system, it had a 200A alternator that as a result, could dump a lot of power into the battery in a short time.

I think using a battery maintainer on the thing, especially if you don't drive it daily, is probably a good idea. I know it let the battery on my older vehicle last lots longer than average - like 7-years and was going strong when I sold it. Prior to that, I'd gone through two batteries.

I don't know the full logic on the PHEV, but maintaining that may also help out. At least, that battery is smaller, so the cost is less when you do have to replace it if it's out of warranty.

[TurtleBoy]

Originally Posted by jad03060

I don't know the size of the alternator on the 40i or 50i, but on an older BMW I had with this system, it had a 200A alternator that as a result, could dump a lot of power into the battery in a short time..

It depends on the equipment, from the Tech Docs:

[Teutonic]

Sorry guys, but many things in this thread didn’t make sense.

30 hours to charge the 12 V battery is ridiculous. I have the same issue with electric motor noise under the hood and then a click in the 48V battery area, reseting the charger everytime. Charging using under the bonet connections is not working. Tried everything you guys said. Nothing works.

I charged my 12 V battery by disconnecting the plus in the trunk (hence disconnecting it from the car) and put a Noco 5. In 5 hours was full. Obviously charging it through the bonnet is not the same as the electronics on the hybrid are protecting something, reseting the charger permanently.

Not sure about your feelings but for me, leaving the car 30 hours with an electric motor working and a clicking noise is a no no. Obviously the manufacturer did not design it this way. And obviously this is not a normal functionality so all I will do is to stress certain components for no reason.
I just wish that the manufacturer will come back and tell us what the heck is going on.
I have tried BMW CTEK charger, Noco 5, Noco 10. All behave the same in my 2021 M340i. Chargers are oerfect as they are new and work on my other two BMWs.

It seems that all of you are experiencing different scenarios and believe you found the answer when actually each case voltage value in your 12 V battery is different, case by case, hence your charging pattern is different as it seems that the 12V battery charging percentage will dictate if the bonet charging works. (See another guys findings in the link bellow).

I have tried every single scenario possible with hood connections and car locked, unlocked, forced dash shut down, bla bla, always I am getting the same crap. Funny, my also 2021 X4 which is also MHT, charges fine.

BMW tech suggested a at least 25 amp charger to overwrite the hybrid electronics. Except that will induce heat to my AGM battery, hence reducing its life. Fast charge comes with a price. We tried severalnew vehicles from the lot and al behaved the same. But dealership doesnt see that as they use German Deutronic professional chargers so they can not replicate the issue in the shop.

I have read another thread on an X7 forum where the guy managed to charge the vehicle via bonnet connections by closing the hood. I will try that.

https://g07.bimmerpost.com/forums/sh....php?t=1781421


What the manual says is not working. Hood open and all that jazz is just BS as it does nothing
Otherwise, I will stick with the trunk charging which is not only stupid but terrible.

All I want to say is SCREW BMW FOR THIS CRAP!
This is unacceptable and BMW should fix this problem!

[GREENPUS]

@bxz I must have got lucky. I had this issue with the flashy light twice and both times only required reprogramming the computer. One thing I learned; people on here that say "just use a trickle charger" on these mild hybrids are full of shit lol. I drive 5 miles a day and worried about my batteries going dead because of that. I figured out how to force the car to charge on its own. So Im good. I do have a highend trickle charger forsale, slightly used lol

Originally Posted by bxz

I found Greenpus' post first after seeing the rear defrost flashing together with dead AC. Today after a week with the X5 left at the dealer, I got it back with the service report.

Here's the story, I bought this car for my Dad in May 2021. He rarely drove, so one day the alarm "replace battery" came on although starting the car didn't seem any problem. I took it out for a spin, thought the alarm would go away after putting on 100 miles. Well, it wouldn't, so I drove for another hour or so, the second day I checked, still there. Went to the dealer and they had to replace with a new battery, the service rep told me to get a battery tender, so I found this CTEK MXS 5.0, which BMW also use with its name on it. I thought now it must have no issue parking there after all. Wrong!, I put the charge on, it took a couple of days for all the 7 lights on, so I thought the charge was done and I could just leave it plugged in. Had no idea when the rear defrost light was flashing til my Dad took the car out for groceries, and the AC was DEAD, although the car status was all OK! no error message, no alarm, nothing. So it went to the dealer again.

It ended with replacing the control unit for the AC and the AC display panel. They also replaced the emergency battery for the telematic control unit under the headlining.

I have no idea why they are making the cars so complicated that a battery charger will rendered the AC unit dead, who knows maybe next time the car won't even turn on.

So much for the high tech, my 2001 ISUZU still runs trouble free with no major service, only thing I did was oil change.

[tcbmhell]

I have tried every single scenario possible as well, never worked. No one can explain how to charge the 12v battery properly. I have given up charging it

Let me know the result that charge the vehicle via bonnet connections by closing the hood.

Originally Posted by Teutonic

Sorry guys, but many things in this thread didn’t make sense.

30 hours to charge the 12 V battery is ridiculous. I have the same issue with electric motor noise under the hood and then a click in the 48V battery area, reseting the charger everytime. Charging using under the bonet connections is not working. Tried everything you guys said. Nothing works.

I charged my 12 V battery by disconnecting the plus in the trunk (hence disconnecting it from the car) and put a Noco 5. In 5 hours was full. Obviously charging it through the bonnet is not the same as the electronics on the hybrid are protecting something, reseting the charger permanently.

Not sure about your feelings but for me, leaving the car 30 hours with an electric motor working and a clicking noise is a no no. Obviously the manufacturer did not design it this way. And obviously this is not a normal functionality so all I will do is to stress certain components for no reason.
I just wish that the manufacturer will come back and tell us what the heck is going on.
I have tried BMW CTEK charger, Noco 5, Noco 10. All behave the same in my 2021 M340i. Chargers are oerfect as they are new and work on my other two BMWs.

It seems that all of you are experiencing different scenarios and believe you found the answer when actually each case voltage value in your 12 V battery is different, case by case, hence your charging pattern is different as it seems that the 12V battery charging percentage will dictate if the bonet charging works. (See another guys findings in the link bellow).

I have tried every single scenario possible with hood connections and car locked, unlocked, forced dash shut down, bla bla, always I am getting the same crap. Funny, my also 2021 X4 which is also MHT, charges fine.

BMW tech suggested a at least 25 amp charger to overwrite the hybrid electronics. Except that will induce heat to my AGM battery, hence reducing its life. Fast charge comes with a price. We tried severalnew vehicles from the lot and al behaved the same. But dealership doesnt see that as they use German Deutronic professional chargers so they can not replicate the issue in the shop.

I have read another thread on an X7 forum where the guy managed to charge the vehicle via bonnet connections by closing the hood. I will try that.

https://g07.bimmerpost.com/forums/sh....php?t=1781421


What the manual says is not working. Hood open and all that jazz is just BS as it does nothing
Otherwise, I will stick with the trunk charging which is not only stupid but terrible.

All I want to say is SCREW BMW FOR THIS CRAP!
This is unacceptable and BMW should fix this problem!