[cszekl]

Originally Posted by zazzau

I guess the question is why do you opt for the trunk rather than the terminal under the hood? Just curious. From your post it sounds like it's just based on old habits from previous cars you've owned.

My thought is, I don’t want to store my car for the winter with the hood open in the garage . I’ve had success this way with all my others. These cars are getting so complicated with all of the new Electrical systems I kind of wish I would of bought before the M340 became a Hybrid.

[cszekl]

Originally Posted by TurtleBoy

The terminals under the hood are not a direct connection to the battery since there is a connection to the IBS. If you don't use the terminals under the hood then the charging may not be registered by the IBS and in some circumstances you will have unwanted results such as not being able to start the vehicle. Perhaps something recently changed so ask your service advisor why it is now acceptable to connect directly to the battery for charging.

Thanks I’ll do that.

[TurtleBoy]

Originally Posted by cszekl

My thought is, I don’t want to store my car for the winter with the hood open in the garage . .

The hood doesn't have to be fully open just not latched.

[zazzau]

Originally Posted by cszekl

My thought is, I don’t want to store my car for the winter with the hood open in the garage . I’ve had success this way with all my others. These cars are getting so complicated with all of the new Electrical systems I kind of wish I would of bought before the M340 became a Hybrid.

I charge mine without the hood open.

[ultrared93]

Originally Posted by zazzau

I charge mine without the hood open.

Page 359 of the online 3-series Owner's Manual says:

[zazzau]

Originally Posted by ultrared93

Page 359 of the online 3-series Owner's Manual says:

Other people haven't had success charging the AGM with the hood open. See link to the post I shared earlier from the G07 forum as well. Personally haven't tried charging with the hood open but if we are to go by the G07 post, leaving the hood closed charges the 12V AGM battery (which is what I care about) rather than the lithium-ion battery. Hope this helps.

[Seaford]

Originally Posted by MBM340

This is correct. I have confirmed it is an AGM battery and you can charge it or use a battery maintainance device in AGM mode just like you would with other cars, but I will say when I hook mine up every 10 minutes or so the car is making electronic sounds from under the hood. Not sure what that is about but no harm appears to be done. I haven't left it on for more than an hour...

Anyone know what the car is doing?

My 330i wouldn’t take any charge at all when I first started using a battery conditioner……..until,I closed the bonnet…..then all was well. I can only guess there is stuff running while the car is unlocked and/or bonnet opening and it doesn’t like external charging during that?

[ultrared93]

Originally Posted by zazzau

Other people haven't had success charging the AGM with the hood open. See link to the post I shared earlier from the G07 forum as well. Personally haven't tried charging with the hood open but if we are to go by the G07 post, leaving the hood closed charges the 12V AGM battery (which is what I care about) rather than the lithium-ion battery. Hope this helps.

I've successfully charged using my Ctek tender/charger 2 or 3 times, always with the hood open and on the AGM setting. The last time, I left the charger on for at least a day after it indicated completion. That seemed to bring the 48V battery up to full charge facilitating my most recent software/firmware upgrade.

[G22b58]

Originally Posted by ultrared93

I've successfully charged using my Ctek tender/charger 2 or 3 times, always with the hood open and on the AGM setting. The last time, I left the charger on for at least a day after it indicated completion. That seemed to bring the 48V battery up to full charge facilitating my most recent software/firmware upgrade.

Interesting. Is it one of the stronger CTEK chargers, what model is it?

[ultrared93]

Originally Posted by G22b58

Interesting. Is it one of the stronger CTEK chargers, what model is it?

Its a unit I've had for quite a while - MUS 4.3.

[Z_Victor1]

Originally Posted by Andybird

My 330i wouldn’t take any charge at all when I first started using a battery conditioner……..until,I closed the bonnet…..then all was well. I can only guess there is stuff running while the car is unlocked and/or bonnet opening and it doesn’t like external charging during that?

Do you mind me asking what battery conditioner/tender have you got?

I've got identical problems to yours in my G22 in that the charger won't go and haven't got round to doing it with the bonnet closed and the tender outside the car (so as to see what's occurring I suppose).

First I was wondering if it was something specific to the Mild Hybrid Technology
Then I thought my C-TEK MX-5 wasn't up to it (but it most certainly is according to it's spec).

Have read a lot of these threads with info about hood up/down, i-Drive forced switched off etc.,

I'll give your method a shot tomorrow, it works for you so I don't see why it shouldn't for me!

So.....bonnet closed, keys away from car, comfort access locking disabled, car unlocked and see what happens!

[Z_Victor1]

...of doing this.

I have just read the BMW SIB 61 01 21

https://static.nhtsa.gov/odi/tsbs/20...88948-9999.pdf

A variety of comments thus far conflict with this. So, I'm not going anywhere near charging the 12V until someone comes up with a method that just "works".

Previously I have been reading methods including opening/closing the bonnet/hood, charging the battery directly, shutting down the i-Drive, etc., etc.,...just crazy.

The thought of totally discharging the 48 V battery resulitng in the requirement for a replacement....seems nuts ...

[zazzau]

Originally Posted by Z_Victor1

...of doing this.

I have just read the BMW SIB 61 01 21

https://static.nhtsa.gov/odi/tsbs/20...88948-9999.pdf

A variety of comments thus far conflict with this. So, I'm not going anywhere near charging the 12V until someone comes up with a method that just "works".

Previously I have been reading methods including opening/closing the bonnet/hood, charging the battery directly, shutting down the i-Drive, etc., etc.,...just crazy.

The thought of totally discharging the 48 V battery resulitng in the requirement for a replacement....seems nuts ...

What I understand is that this issue is likely to happen when charging with the hood closed. Hence if you charge with the hood closed for extended periods, you are actually NOT charging the battery (manual is clear about this) and depending on how long the car is parked the battery could drain.

The takeaway is to learn how to charge the correct way. Haven't read a single thread with reported issues of battery drain from charging.

Been charging mine (same way it's done during service) with zero issues. I keep mine closed but not latched.

[nealjay]

have a m440 battery is at 60 % remote start won't work figured battery low
got tech 4.3 tried charging it 24 hours. and nothing. stayed on position 3 and battery was still at 60%. and one or two. success stories hear but mostly its. people who cant. age in the back lithium in the front
makes noises while charging. like clicks like others said but doesnt seem to charge it.
would bmw charge it at the service center? imma keep trying but seems useless.

[TurtleBoy]

Originally Posted by nealjay

have a m440 battery is at 60 % remote start won't work figured battery low
got tech 4.3 tried charging it 24 hours. and nothing. stayed on position 3 and battery was still at 60%. and one or two. success stories hear but mostly its. people who cant. age in the back lithium in the front
makes noises while charging. like clicks like others said but doesnt seem to charge it.
would bmw charge it at the service center? imma keep trying but seems useless.

As you said, many people have had that experience. I have tried it twice as a test and have never had it successfully charge.

[bavarianride]

Originally Posted by ultrared93

Its a unit I've had for quite a while - MUS 4.3.

Yes CCTEK MUS 4.3 does complete charge cycles on my 2021 330i (dual storage non-48V) with the hood opened, but I don't know if lithium battery is charged or not.

[bavarianride]

Originally Posted by cszekl

I have read that warning in the manual also. That’s why I asked the dealership advisor. The positive and negative Terminals under the hood are the same terminals that are on the battery in the trunk under the carpet. So, the
Terminals under the hood are an extension to the battery in the trunk do to design location. No issues can happen to the 12 volt system when using a Quality battery Tender and pigtail off of the battery.
I made sure my dealership approved of my set up. I think maybe we over thinking things here. Maybe a BMW tech could chime in on the topic.

I think charging from the jump terminals under hood provides extra surge protection for the rest of sensitive electronics in the car, while charging directly through the battery terminals does not.

[anandn]

Originally Posted by nealjay

have a m440 battery is at 60 % remote start won't work figured battery low
got tech 4.3 tried charging it 24 hours. and nothing. stayed on position 3 and battery was still at 60%. and one or two. success stories hear but mostly its. people who cant. age in the back lithium in the front
makes noises while charging. like clicks like others said but doesnt seem to charge it.
would bmw charge it at the service center? imma keep trying but seems useless.

This is the CTEK charger I am using and it is working fine in my 2023 440i convertible. It took about 20h to get to stage 7. Car hood is unlatched and the clamps are attached to the dummy terminals in the engine bay. I used a CTEK extension cord so that I could place the charger on the floor of my garage.

https://smartercharger.com/products/ctek-mxs-5-0

[bavarianride]

Originally Posted by zazzau

https://www.amazon.com/dp/B0045F3SGY..._Y2FRxkkj47qcN

Wow this is a 25A charger, I guess u can use it for ECU updates too.

[anandn]

Originally Posted by Z_Victor1

...of doing this.

I have just read the BMW SIB 61 01 21

https://static.nhtsa.gov/odi/tsbs/20...88948-9999.pdf

A variety of comments thus far conflict with this. So, I'm not going anywhere near charging the 12V until someone comes up with a method that just "works".

Previously I have been reading methods including opening/closing the bonnet/hood, charging the battery directly, shutting down the i-Drive, etc., etc.,...just crazy.

The thought of totally discharging the 48 V battery resulitng in the requirement for a replacement....seems nuts ...

The CTEK MXS 5 charger works fine in my 2023 440i convertible. It is not going to charge the Li ion hybrid battery and there is no need. That battery does not need to be charged unless the car is sitting for a year or more. Self discharge rates of Li ion batteries are very low (< 2% per month). The 12 v starter battery is altogether different. That battery runs all the electronics, the starter, the latches, locks etc. You don't want that dead. In my previous car a Porsche 911, if the 12 v battery died, one couldn't even open the frunk to access the dummy terminals for a jump. Seems the same in my convertible. Leaving the hood open whether using a charger or not seems like a good idea.

[zazzau]

Originally Posted by bavarianride

Wow this is a 25A charger, I guess u can use it for ECU updates too.

Yeah. Works really well. I used it to maintain charge when coding.

[johndoe1983]

Bmw has installed a 4 amp battery tender on my 440i.

They told me to disconnect the 48 volt terminal on the battery and let the charger do it’s job. The hood is not lock.

My car will be stop for 5 full months. Hope this will work.

What do you think?

Thanks