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Steve
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Discussion Starter · #1 ·
Hi
As we settle in to Winter, I attached my CTEK 4.3 trickle charger to my 2021 M440i. However, it is not progressing past step 3 (over a week). This worked fine on my 2019 Z4. Anything different about charging this vehicle? Need a different charger?

Thanks...

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Nuclear engineer
02/2012 X5 35d M57Y CPO 110K miles NOKIAN WR G3 25K miles
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21,405 Posts
Read your owners manual page 9 indicating Step 3 BULK charge is limited to 20 hours. 20 hours X 4.3 Amps = 86 Ampere-hours and not enough to fully charge a > 90 AH nominal battery.

There is nothing wrong with interrupting a charge at any time. Consider it an interrupted charge and restart when it is convenient for you. Charge until you get to Step 7 FLOAT or an error describe on page 11.

If you have loads on the charger other than the battery then the charging current will be divided and not charge the battery at 4.3 Amps. 4.3 Amps is the maximum that the CTEK 4.3 MUS will putout.
 

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Steve
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373 Posts
Discussion Starter · #3 ·
Read your owners manual page 9 indicating Step 3 BULK charge is limited to 20 hours. 20 hours X 4.3 Amps = 86 Ampere-hours and not enough to fully charge a > 90 AH nominal battery.

There is nothing wrong with interrupting a charge at any time. Consider it an interrupted charge and restart when it is convenient for you. Charge until you get to Step 7 FLOAT or an error describe on page 11.

If you have loads on the charger other than the battery then the charging current will be divided and not charge the battery at 4.3 Amps. 4.3 Amps is the maximum that the CTEK 4.3 MUS will putout.
Thanks Doug but not sure that's it. I'm using the same way as on my Z4 and did not have this issue. Why on the M440i?
 

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Nuclear engineer
02/2012 X5 35d M57Y CPO 110K miles NOKIAN WR G3 25K miles
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21,405 Posts
Thanks Doug but not sure that's it. I'm using the same way as on my Z4 and did not have this issue. Why on the M440i?
What “that’s it”?
 

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Steve
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373 Posts
Discussion Starter · #5 ·

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Your charger should be fine. How old is your battery? I have a CTEK charger and it would not go further than bulk stage due to a “dud” new battery. Exchanging it under warranty after a month solved the issue. If the battery cannot maintain a charge it may never go past the CTEK charger detections. It’s a 2021 BMW so the battery should be new. Still guessing a bad battery or a bad connection on your charging wiring.


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I believe you have a mild hybrid like the M340i correct? I found this on another BMW forum:

I have successfully charged battery three times (MY21 40i) using the steps below:

1. Start the vehicle and turn off, then turn off the iDrive manually by pressing the volume knob a few seconds. This ensures iDrive go into sleep mode (also known as idle state, see details on this at the end of the post). This seems to be the trick. 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).

2. Open door, exit car, open bonnet, and close door (don't lock yet). Keep the bonnet open until charging is complete (THIS IS A MUST), two U-shaped bonnet latches should not go into the sockets (this is how vehicle knows if the bonnet remains open or not).

3. Connect charger cables in this sequence: positive > negative > charger power.

4. Lock the car. Don't open doors while the car being charged, this might cause charging/battery related error codes being displayed on iDrive later. Note that you might hear a few actuator motors makes brief noises between engine bay and dashboard as if those are trying to open/close something, this is normal. A few LEDs on buttons around driver seat will continue to be illuminated for about 15 minutes and turn off automatically after a while, this is also normal.

5. Move away from the car and don't do anything that might wake up the iDrive.

6. When battery is fully charged disconnect the cables in reverse order: charger power > negative > positive. Close hood/bonnet.

Depending on the charger type and battery charge state it might take long, I usually keep it going overnight.

Hi
As we settle in to Winter, I attached my CTEK 4.3 trickle charger to my 2021 M440i. However, it is not progressing past step 3 (over a week). This worked fine on my 2019 Z4. Anything different about charging this vehicle? Need a different charger?

Thanks...

View attachment 1045845 View attachment 1045846
 

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Steve
Joined
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373 Posts
Discussion Starter · #8 ·
I believe you have a mild hybrid like the M340i correct? I found this on another BMW forum:

I have successfully charged battery three times (MY21 40i) using the steps below:

1. Start the vehicle and turn off, then turn off the iDrive manually by pressing the volume knob a few seconds. This ensures iDrive go into sleep mode (also known as idle state, see details on this at the end of the post). This seems to be the trick. 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).

2. Open door, exit car, open bonnet, and close door (don't lock yet). Keep the bonnet open until charging is complete (THIS IS A MUST), two U-shaped bonnet latches should not go into the sockets (this is how vehicle knows if the bonnet remains open or not).

3. Connect charger cables in this sequence: positive > negative > charger power.

4. Lock the car. Don't open doors while the car being charged, this might cause charging/battery related error codes being displayed on iDrive later. Note that you might hear a few actuator motors makes brief noises between engine bay and dashboard as if those are trying to open/close something, this is normal. A few LEDs on buttons around driver seat will continue to be illuminated for about 15 minutes and turn off automatically after a while, this is also normal.

5. Move away from the car and don't do anything that might wake up the iDrive.

6. When battery is fully charged disconnect the cables in reverse order: charger power > negative > positive. Close hood/bonnet.

Depending on the charger type and battery charge state it might take long, I usually keep it going overnight.
thank you for the detailed post. Much appreciated. And yes it is the mild hybrid. I was wondering if that had any impact.
 

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Steve, Depending on the state of your battery, it may take a day or two to reach stage 7. CTEK only charges at a max of 4ish amps so as not to damage the battery. Make sure they hood is "open" meaning that the U bolts on the hood are not down in to the switches at the front of the engine. My understanding is that "hood open" separates the 12v circuit from the 48v? (if I recall) hybrid battery. I use a CTEK on my '21 M340 and have had no problems charging it.....just give it time. In my M340 I notice electric motor noises in the driver side bulkhead area. Also the red triangle (hazard) in the center will stay lit as well as the backlights around the headlight controls. As the battery charges up closer to 13 volts those lights will go out. I've been creating a table of volts vs observations on the car to pinpoint at which voltage various items (electric motors) stop cycling. There is lots of info on forums (other X_ BMWs have the same issue). It's frustrating to pay this much for a car and have to jump through hoops to charge it.
 

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where da clutch at ?
2020 BMW 230i
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3,479 Posts
SLIP, take it from a guy that knows,
PLEASE read my threads,

Get a PROPER battery tester on that battery (directly on it not at the jump posts). I use a solar Ba9, you are going to find the readings are not good, I suspect as another poster has said a DUFF cell.

My DUFF battery would stay for AGES on 4 or 5, would go up to 7, then drop or not even do that. MY new battery goes up evenly then jumps right to float and stays there,

I spent months on this crappy car, Your M440 is a BATTERY HOG, it has a shed load of computers, you wake that thing up and boom,

My dashcam and probably BMW FUBARD my battery a new battery fixed that,

CHECK your battery that is THE ONLY WAY, stand on your head turn around count to 3, open doors close doors whistle dixie. Spend $40 on a BA9
Only tried and tested way

Been there got the tshirt, read the book and ate the hoagie



Hi
As we settle in to Winter, I attached my CTEK 4.3 trickle charger to my 2021 M440i. However, it is not progressing past step 3 (over a week). This worked fine on my 2019 Z4. Anything different about charging this vehicle? Need a different charger?

Thanks...

View attachment 1045845 View attachment 1045846
 

·
where da clutch at ?
2020 BMW 230i
Joined
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3,479 Posts
 
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