[Waterdog]

Does the charging of the battery vary by which drive mode the car is in?

[Bking60]

Originally Posted by TurtleBoy

You are getting closer but I think you are qualifying enough to understand how things are working. As stated before, and as the schematics and tech docs show, there is only one Safety Battery Terminal and that is on the rear battery which is a direct connection to the terminal under the hood. So the voltage shown by the terminal under the hood is the voltage of the rear battery.

The PCU determines when the auxiliary battery is used and charged. Parallel does not mean they do the same thing and the same time.

Attachment 3064330

Attachment 3064329

The batteries are in parallel.
The only things that can change that is a safety disconnect and another disconnect at the front battery that is controlled by a controller. So parallel charging and parallel normal operation. You might catch on if I keep saying this but not likely.

[TurtleBoy]

Originally Posted by Bking60

The batteries are in parallel.
The only things that can change that is a safety disconnect and another disconnect at the front battery that is controlled by a controller. So parallel charging and parallel normal operation. You might catch on if I keep saying this but not likely.

Sort of odd that all information from BMW is against what you are saying and yet you still insist you are correct. Oh well, you not understanding how the system works isn't really important. The important thing is that the correct information, schematics, relevant tech docs, etc. have been posted so future readers of the thread can see how the system is set up and operates.

[TurtleBoy]

Originally Posted by Waterdog

Does the charging of the battery vary by which drive mode the car is in?

Back when I did some testing on that it seemed like Eco Pro did not show the charging has often as the other modes, especially when coasting. I don't drive in Eco Pro so don't have a lot of experience with it. May be someone who does can chime in.

[Bking60]

Originally Posted by TurtleBoy

Sort of odd that all information from BMW is against what you are saying and yet you still insist you are correct. Oh well, you not understanding how the system works isn't really important. The important thing is that the correct information, schematics, relevant tech docs, etc. have been posted so future readers of the thread can see how the system is set up and operates.

Docs you posted backs up what I'm saying. Prove otherwise because you have not. Only proved that you can't follow the wiring diagram.

[TurtleBoy]

Originally Posted by Bking60

Docs you posted backs up what I'm saying. Prove otherwise because you have not. Only proved that you can't follow the wiring diagram.

Never mind, I see you haven't been reading the information I posted that clearly states the two batteries do not operate at the same time. This will be my last post to you on this subject since I'm just wasting my time and the forum's space responding to you since you obviously are not looking at the information BMW has supplied.

As stated in the tech docs, the auxiliary battery is for running the electronics when the engine is in the start/stop state. It is not being used when the engine is running. There is a reason it is called an auxiliary battery.

Just take a step back and think about it logically. We'll forget that BMW has said they aren't operating the same time and go with your situation that the two batteries are directly connected, whether that is even possible we won't worry about, and operating together as one battery. Why would they go through all of the trouble to do that when they could have just used a bigger battery?

[eelnoraa]

Originally Posted by Bking60

The batteries are in parallel.
The only things that can change that is a safety disconnect and another disconnect at the front battery that is controlled by a controller. So parallel charging and parallel normal operation. You might catch on if I keep saying this but not likely.

The battery in parallel part doesn’t make sense from electrical point of view. When you parallel connect two voltage sources, if they don’t perfect match, which 100% will not because different type, they will fight against each other. Think about it, one want to generate 13.2V. The other wants to generate 13.5V, for example. The the case of battery, the higher voltage one will attamp to charge the lower voltage one. Or the lower voltage one will try to load down the higher voltage one. Either way, it isn’t efficient to say the least, if this type of connection doesn’t break anything.

[Bking60]

Success! You are now stating things that are mostly accurate.

You started out saying:

The terminals in the front are for the rear battery. The secondary battery under the hood, AGM or Li depending on options, doesn't have terminals showing.

(That statement is false)

[TurtleBoy]

Originally Posted by Bking60

Success! You are now stating things that are mostly accurate.

You started out saying:

The terminals in the front are for the rear battery. The secondary battery under the hood, AGM or Li depending on options, doesn't have terminals showing.

(That statement is false)

Nice try, but folks here are smart enough to not buy the dishonest tactic of now throng to take my position.

My statement is 100% accurate.

[Bking60]

Originally Posted by eelnoraa

The battery in parallel part doesn’t make sense from electrical point of view. When you parallel connect two voltage sources, if they don’t perfect match, which 100% will not because different type, they will fight against each other. Think about it, one want to generate 13.2V. The other wants to generate 13.5V, for example. The the case of battery, the higher voltage one will attamp to charge the lower voltage one. Or the lower voltage one will try to load down the higher voltage one. Either way, it isn’t efficient to say the least, if this type of connection doesn’t break anything.

I agree, but BMW did it.

[Bking60]

Originally Posted by TurtleBoy

Nice try, but folks here are smart enough to not buy the dishonest tactic of now throng to take my position.

My statement is 100% accurate.

Dishonest??????? You wrote that crap.

Sorry but I verified this on the car. Try looking and checking circuits on your car.

[TurtleBoy]

Originally Posted by eelnoraa

The battery in parallel part doesn’t make sense from electrical point of view. When you parallel connect two voltage sources, if they don’t perfect match, which 100% will not because different type, they will fight against each other. Think about it, one want to generate 13.2V. The other wants to generate 13.5V, for example. The the case of battery, the higher voltage one will attamp to charge the lower voltage one. Or the lower voltage one will try to load down the higher voltage one. Either way, it isn’t efficient to say the least, if this type of connection doesn’t break anything.

Just ignore him eelnoraa, at this point we can only assume he is being a troll. Unfortunately we get them every once and awhile and thankfully they usually leave after no one engages. The bad part is they usually end up misleading folks with their nonsense.

[Bking60]

I'm out of here, but batteries stay in parallel unless something switches one off.

[Bking60]

Originally Posted by TurtleBoy

Just ignore him eelnoraa, at this point we can only assume he is being a troll. Unfortunately we get them every once and awhile and thankfully they usually leave after no one engages. The bad part is they usually end up misleading folks with their nonsense.

Boy is biggest troll I've seen with many years on forums.

[Waterdog]

Originally Posted by TurtleBoy

Back when I did some testing on that it seemed like Eco Pro did not show the charging has often as the other modes, especially when coasting. I don't drive in Eco Pro so don't have a lot of experience with it. May be someone who does can chime in.

Thanks!

[weinerbarn]

Originally Posted by gabru

Hello All, I have a 2022 X5 and within last 2 weeks I found the battery dead 2 times. Both times this happened as I parked the car the night before and found it irresponsive the next morning.
I got the car checked by the dealership after the first incident and they couldn't really find anything wrong. But now it happened again which is really frustrating.
I thought of getting input based on anyone else having the same experience here. Thanks for any input

Did the software get upgraded recently and what is on it currently? Curious as I saw similar notes on another forum.

[Tejas1836]

Based upon the schematic 4.1.2 on page 2 and in the absence of any blown fuses or SBT
-The main (rear) battery is always online and always providing power, ICE running or not.
-Both batteries are connected in parallel (have to be otherwise you would have 24 volts spewing out if connected in series) when the auxiliary battery circuit is closed.
-The auxiliary battery circuit, when instructed by the DME, is closed providing additional power if needed like stop-start mode, emergency electrical in the event the SBT circuit is open.

Regards

ETA: I ran out of popcorn

[TurtleBoy]

Originally Posted by Tejas1836

Based upon the schematic 4.1.2 on page 2 and in the absence of any blown fuses or SBT
-The main (rear) battery is always online and always providing power, ICE running or not.
-Both batteries are connected in parallel (have to be otherwise you would have 24 volts spewing out if connected in series) when the auxiliary battery circuit is closed.
-The auxiliary battery circuit, when instructed by the DME, is closed providing additional power if needed like stop-start mode, emergency electrical in the event the SBT circuit is open.

Regards

ETA: I ran out of popcorn

Thanks but he didn't believe the BMW docs I posted so he probably won't believe you. Well summarized though. The only difference from what I have seen is that it will not provide power when the SBT is triggered.

[Tejas1836]

I think that both of you are right.

The auxiliary battery will provide emergency power for things like cellular SOS, flashers, probably door locks and windows...[in the event of a SBT open circuit]

[TurtleBoy]

Originally Posted by Tejas1836

I think that both of you are right.

The auxiliary battery will provide emergency power for things like cellular SOS, flashers, probably door locks and windows...[in the event of a SBT open circuit]

Gotcha, perhaps the article I saw was mistaken.

He is only correct on the point that he and I agreed on which was one also noted in the docs, that being that they were connected in parallel. As you have stated, he is not correct about how the auxiliary battery operates.

Edit: It was an SIB concerning the system. Perhaps there is a special circuit for what you are describing. Maybe we'll run across more info.



https://static.nhtsa.gov/odi/tsbs/20...66386-9999.pdf

[Tejas1836]

No, you are correct, I am thinking of something else. The cellular SOS has a lithium battery in the telematics box

[Brigitte]

Originally Posted by TurtleBoy

BMW has been using their Brake Energy Regeneration system on vehicles for many years.

Is this unique to BMW? I mean the battery recharging system is different in other brands of cars?