[Rob_G77]

I have a 2024 X5 40i with about 3500kms. I've noticed in the past 6 weeks that the mild hybrid battery doesn't seem to be keeping the vehicle off very long while stopped at a red light. A lot of the time now the vehicle will restart before the light even turns green. Yesterday while stopping the engine didn't even turn off at times.

This mirrors the mild hybrid behavior I've experienced before with my other BMW's and I think what's the point of it all when the system is only going to keep the engine off for 10-15 seconds. I am aware that the battery charges while coasting so I do coast A LOT when approaching red lights and other situations where I have to stop. It doesn't seem to really help though.

When the vehicle was brand new, the system could keep the car off for a few minutes before restarting. Yes it's cold outside, but only around freezing and I keep the vehicle in an insulated garage when not driving it.

I think it is a terrible design.

Rob

[swainbmw]

Originally Posted by Rob_G77

I have a 2024 X5 40i with about 3500kms. I've noticed in the past 6 weeks that the mild hybrid battery doesn't seem to be keeping the vehicle off very long while stopped at a red light. A lot of the time now the vehicle will restart before the light even turns green. Yesterday while stopping the engine didn't even turn off at times.

This mirrors the mild hybrid behavior I've experienced before with my other BMW's and I think what's the point of it all when the system is only going to keep the engine off for 10-15 seconds. I am aware that the battery charges while coasting so I do coast A LOT when approaching red lights and other situations where I have to stop. It doesn't seem to really help though.

When the vehicle was brand new, the system could keep the car off for a few minutes before restarting. Yes it's cold outside, but only around freezing and I keep the vehicle in an insulated garage when not driving it.

I think it is a terrible design.

Rob

I would think it’s the outside temperature

[RNorb]

Originally Posted by Rob_G77

I have a 2024 X5 40i with about 3500kms. Yesterday while stopping the engine didn't even turn off at times.


Rob

A lot of us would wish the car would never turn off when stopping!

[X6ix GTA]

Originally Posted by Rob_G77

I have a 2024 X5 40i with about 3500kms. I've noticed in the past 6 weeks that the mild hybrid battery doesn't seem to be keeping the vehicle off very long while stopped at a red light. A lot of the time now the vehicle will restart before the light even turns green. Yesterday while stopping the engine didn't even turn off at times.

This mirrors the mild hybrid behavior I've experienced before with my other BMW's and I think what's the point of it all when the system is only going to keep the engine off for 10-15 seconds. I am aware that the battery charges while coasting so I do coast A LOT when approaching red lights and other situations where I have to stop. It doesn't seem to really help though.

When the vehicle was brand new, the system could keep the car off for a few minutes before restarting. Yes it's cold outside, but only around freezing and I keep the vehicle in an insulated garage when not driving it.

I think it is a terrible design.

Rob

The engine is turning on to maintain the cabin temperature. You will notice the same behavior when it's hot out there. I doubt the 48v battery would lose capacity so quickly.

[Rob_G77]

Originally Posted by swainbmw

I would think it’s the outside temperature

I thought so too, but it's around freezing which isn't that cold.

I know others would prefer to not have it at all. I'm in that camp too, but we gotta live with the design.

Rob

[davchr]

Why would the condition of the 48V battery affect the length of time the engine stays off at a stop light? On other vehicles that I have the ASS will not activate when the starting battery is low. This is a good indicator that the starting battery needs to be replaced. Or, if the vehicle has a secondary ASS battery, DON'T replace it and your ASS is permanently disabled. ASS problem solved!

[TurtleBoy]

As mentioned above, it is the temperature and no reflection on the state of your 48v battery.

[Rob_G77]

Originally Posted by TurtleBoy

As mentioned above, it is the temperature and no reflection on the state of your 48v battery.

Ok... fair point it might be. But my experience has been that even when warmer the system doesn't keep the engine off too long. My thought is then what is the point of turning off the engine if it has to turn it back on in 10 seconds and before the light is even green. This is where it is such a stupid design. I mean, it's supposed to stop emissions when you are stopped and it can't even do that very well.

Rob

[TurtleBoy]

Originally Posted by Rob_G77

Ok... fair point it might be. But my experience has been that even when warmer the system doesn't keep the engine off too long. My thought is then what is the point of turning off the engine if it has to turn it back on in 10 seconds and before the light is even green. This is where it is such a stupid design. I mean, it's supposed to stop emissions when you are stopped and it can't even do that very well.

Rob

I have never experienced that or heard of others having the same thing happen unless it was tied to the HVAC needs. You may want to get yours checked if you think there is an issue but my feeling is that it is 100% normal.

[davchr]

Originally Posted by TurtleBoy

I have never experienced that or heard of others having the same thing happen unless it was tied to the HVAC needs. You may want to get yours checked if you think there is an issue but my feeling is that it is 100% normal.

My Porsche and Toyota start the motor when turning the steering wheel and for the A/C. The Toyota does such a good job with the ASS that it is barely noticeable and I never spent time disabling it.

[tooloud10]

I don't think 2k miles on a '24 is long enough to make any big generalizations about how the system 'usually' works.

The system seems to be working fine based on the details provided, and there are multiple inputs that control how it behaves so I wouldn't overthink it because of a few second difference in the way it activates from one day to the next.