[turbobeagle]

Anyone else tried to charge up their batteries lately with the mild hybrid? I’ve been doing a lot of coding, rattle-hunting, detailing etc. lately with the doors open and stereo going so I figured I should replenish.

Setup:

• Ctek 5 amp charger on the prescribed BMS posts in the engine compartment.
• Hood open
• Doors closed but unlocked.

Results:

• Whirring/clicking noise throughout the charge session. Every 2-3 minutes.
• About 6 hours until ctek hit green (stage 7).
• 460 watt-hours pulled (measured at the socket)
• Warning on instrument cluster and idrive screen after. Went away after starting engine.
• The 48v battery started at 4 bars and didn’t change. So I assume all this charge went only to the AGM 12v.

This is the second time I’ve done this. The first time (right after brining it home), it only pulled 170 watt-hours so it seems I did drain it some. I’ll try to resist messing with this again.

[lfdal54]

There's another thread where I posted some stuff trying to figure out some rhyme or reason as to how the 48v battery charges and the best I came away with is that "it does what it does". I really wish I had a better understanding of the system overall. Typically mine sits at around one or two blocks out of the five illuminated. Since I've left the screen activated that shows the drive train I've noticed it's fairly verbose with what's going on.

[glennbk]

I'm thinking it doesn't charge much is to prolong life. I still have yet to engage the hybrid boost function.

[br438]

My observation, in daily driving, is that the mild hybrid system charges more in sport mode - possibly because they can guise the regenerative braking as aggressive braking/driving?

Otherwise, it stays at 2 bars or 3 bars on the "charge indicator" screen.

[ASAP]

my head hurts trying to figure out whats going on here

[turbobeagle]

Originally Posted by ASAP

my head hurts trying to figure out whats going on here

In short, I tried to use a Ctek car battery charger and it seems to have worked, but did result in an error message that went away once the engine was started.

[ASAP]

Originally Posted by turbobeagle

In short, I tried to use a Ctek car battery charger and it seems to have worked, but did result in an error message that went away once the engine was started.

Right but how is any of this related to the hybrid system? And to be honest, with your low mileage, I would just drive the car for like 20 minutes instead lol.

[turbobeagle]

Originally Posted by ASAP

Right but how is any of this related to the hybrid system? And to be honest, with your low mileage, I would just drive the car for like 20 minutes instead lol.

Because people have been having a hard time using battery chargers on cars with the mild hybrid system.

https://g20.bimmerpost.com/forums/sh....php?t=1779237

I fully agree my use case was frivolous . But others who are leaving their vehicles dormant for long stretches need to hook up chargers.

[lfdal54]

Originally Posted by glennbk

I'm thinking it doesn't charge much is to prolong life. I still have yet to engage the hybrid boost function.

With the display screen, I've seen the message that it's assisting pop up. I forget the exact syntax, unfortunately. I'll try to pay more attention next time.

[FutureTrunks_M40i]

The 48V battery charges whenever you coast (let off the gas pedal while the car is in motion) or apply brakes while the car is in motion.

[freshxdough]

To charge the 48v you probably need a bigger charger than just a small trickle charger. The 48v system can charge from the 12v system if it is being charged with a sufficient charger connected and hood open. Although if you’re driving the car normally there’s really no point to externally charger the 48v battery as it is maintained by the system itself. It’s not a PHEV.

[glennbk]

That brings another good question. If you shot off auto start/stop, does it also shut off the hybrid charging system?

[br438]

Originally Posted by FutureTrunks_M40i

The 48V battery charges whenever you coast (let off the gas pedal while the car is in motion) or apply brakes while the car is in motion.

not whenever.... when you initiate braking. For instance, if you are in eco pro, and let off the gas at 70mph on the interstate, the car shuts off the ICE, and freewheels. It does not regenerative brake until you brake. (not a 1 pedal drive).

[AllBlackBimmer]

My understanding is - the "mild hybrid" system is not like a typical hybrid or electric car where you need to "charge it" ... I am pretty sure you can't just drive in an "electric" mode as you can with a real hybrid.

The BMW system just "supplements" things when needed, or if needed... its helps with start/stop, coasting, a better MPG

But I am pretty sure you don't charge the "mild hybrid system" as your car will charge it, or not charge it, as needed.
Unlike the car's "regular" battery that all cars have... that you of course can charge with something like a ctek trickle charger.

Don't take my word, but this is my understand.
I purposely bought a BMW without this "mild hybrid" system. As with everything new, it usually takes a generation of models to work out the kinks. When BMW went turbo, as good as the n54 enginers were, there were problems with HPFP, carbon buildup etc... but look at the turbo engines now and people may say the b58 is one of the BEST on the market.
good luck.

[freshxdough]

Originally Posted by AllBlackBimmer

My understanding is - the "mild hybrid" system is not like a typical hybrid or electric car where you need to "charge it" ... I am pretty sure you can't just drive in an "electric" mode as you can with a real hybrid.

The BMW system just "supplements" things when needed, or if needed... its helps with start/stop, coasting, a better MPG

But I am pretty sure you don't charge the "mild hybrid system" as your car will charge it, or not charge it, as needed.
Unlike the car's "regular" battery that all cars have... that you of course can charge with something like a ctek trickle charger.

Don't take my word, but this is my understand.
I purposely bought a BMW without this "mild hybrid" system. As with everything new, it usually takes a generation of models to work out the kinks. When BMW went turbo, as good as the n54 enginers were, there were problems with HPFP, carbon buildup etc... but look at the turbo engines now and people may say the b58 is one of the BEST on the market.
good luck.

The current 48v system can not drive on only electric power as it uses an SGR which is a starter motor generator, which is a fancy alternator. The newest 48v system on the B58TU2 and S68 both use an electrical machine in the transmission which is capable of driving the car on pure electric at very low load and speed. Car is almost always exclusively started with the e machine as well and not the pinion starter, even on cold start.

[Keefy]

Originally Posted by freshxdough

The current 48v system can not drive on only electric power as it uses an SGR which is a starter motor generator, which is a fancy alternator. The newest 48v system on the B58TU2 and S68 both use an electrical machine in the transmission which is capable of driving the car on pure electric at very low load and speed. Car is almost always exclusively started with the e machine as well and not the pinion starter, even on cold start.

MY22 M40d obviously has the Mild Hybrid Technology, is there any risk of any malfunction due to the car not being driven for a prolonged period of time?

I only ask as my car has hardly moved since December 12th due to me breaking my leg, It was driven on the 4th Jan for an hour but that's it.

Note: prior to the 4th Jan, there was a low battery warning when I tried to remote start the air con but no warning today when I repeated the remote air con start. Was thinking the 1 hour drive on the 4th had charged everything back up again?

[freshxdough]

Originally Posted by Keefy

MY22 M40d obviously has the Mild Hybrid Technology, is there any risk of any malfunction due to the car not being driven for a prolonged period of time?

I only ask as my car has hardly moved since December 12th due to me breaking my leg, It was driven on the 4th Jan for an hour but that's it.

Note: prior to the 4th Jan, there was a low battery warning when I tried to remote start the air con but no warning today when I repeated the remote air con start. Was thinking the 1 hour drive on the 4th had charged everything back up again?

It would get a trickle charger or have someone drive it like once a week or so.

[Burr001]

Wanted to bump this thread as I have a question about the 48v battery under the hood for those who have the mild hybrid system.

What is the life span? Nothing wrong with mine for now just trying to do some research before I get to that point.

I see that a replacement from BMW is anywhere from 1600 to 2gs. Stock part # 61 21 5A38DE3 ..If it was to be replaced is there coding and register needed like the 12V rear battery?

I found antigravity battery to have replacements for around a 1000 depending on which Ah you get.

Which amp hr will work 24ah, 40ah or 60ah? Does the BMW system have a specific amp hr to use?

https://antigravitybatteries.com/pro...tive/ag-h6-rs/

And just in case your looking for the 12V rear...but its 2x pricey in comparison to OEM.

https://antigravitybatteries.com/pro...tive/ag-h7-rs/

install vid in case you needed more info.

[das boots]

Very interesting thread now that I have the '24 G02 for 7 months now. Need to learn more on the 48v Mild Hybrid system.

[Sportstick]

Charging and possibly overheating a hybrid’s lithium ion battery may be inviting needless risk of triggering a thermal runaway. It’s not a PHEV. I suggest you leave it alone. Google for more background.

[glennbk]

Originally Posted by Sportstick

Charging and possibly overheating a hybrid’s lithium ion battery may be inviting needless risk of triggering a thermal runaway. It’s not a PHEV. I suggest you leave it alone. Google for more background.

This is probably one part you want to leave for the dealership. As for the 12v in the cargo area, you can change that with an H8 AGM. Need to re-program the system with ISTA or BimmerLink.