Aux Battery hide and seek?

CnSky · 07-25-2021, 05:24 PM

On the 530E G30 can anyone tell me for sure 100% where the Aux battery is?

I know I have one as it needs changing and as I have bimmer code etc I want to do it myself but the manual and other sources seem split between the trunk or the hood.

I can see the following but the second photo I beliebv is the motor electonics unit so no battery under the hood.

In the back I can only see a single battery where is this Aux battery hiding?

CHECKERED · 07-25-2021, 05:53 PM

middle of the trunk under some removable sheet metal

http://135jik1bbhst1159ri1ax2pj.wpen...xtrication.pdf

CnSky · 07-25-2021, 05:56 PM

Thanks, wonder how the hell I can access it will try tomorrow.

CnSky · 07-26-2021, 11:08 AM

So is this the additional battery below the trunk floor weird as it's 90ah and the other is only 60 I would've expected it the other way around.

bopjensen · 07-27-2021, 02:22 AM

Hi

How do you know it needs charging?

Can't you just start the car and go for a drive?

Front bat is AUX the one in the back is for starting engine.

you can charge them by connecting a charger to the two jump start studs in the engine bay left side front and back.

Best regards Bo

CnSky · 07-27-2021, 03:17 AM

Bo I have a fault code Aged aux battery when checking with ISTA.

The battery is beyond saving when this happens as it's not holding enough voltage.

Aux battery no 3 is under the hood on the G31 which powers the air suspension and active rear steering.

On the G30 it's definitely one of the two in the trunk as there is none under the hood but I just can't figure out which one it is 100% as even the shop manual isn't clear.

You can't charge the auxiliary batteries with a charger they only charge when the engine is running via the dedicated management charger and BMW state not to attach a battery charger to them to avoid damaging the dedicated system.

The two studs under the hood don't connect to the auxiliary batteries at all they only go to the starter battery.

QUOTE=bopjensen;27849286]Hi

How do you know it needs charging?

Can't you just start the car and go for a drive?

Front bat is AUX the one in the back is for starting engine.

you can charge them by connecting a charger to the two jump start studs in the engine bay left side front and back.

Best regards Bo[/QUOTE]

bopjensen · 07-27-2021, 07:20 AM

Hi
Sorry i misread “changing” as “charging” in your original post 🤭

Best regards Bo

430Scud · 07-27-2021, 03:42 PM

[QUOTE

You can't charge the auxiliary batteries with a charger they only charge when the engine is running via the dedicated management charger and BMW state not to attach a battery charger to them to avoid damaging the dedicated system.

The two studs under the hood don't connect to the auxiliary batteries at all they only go to the starter battery.
[/QUOTE][/QUOTE]

So I have learned from another user that it is okay to charge the under hood battery, even though BMW advises it may risk damaging the isolation circuitry. He had been doing if for some time.

I started charging the battery occasionally, leaving my battery tender connected for up to two or three weeks at a time. Been over a year with no repercussions. Note I use a 4amp battery tender....I would not recommend using anything larger amperage, as that may be the reason for the caution from BMW.

LogicalApex · 07-27-2021, 04:07 PM

Quote:

Originally Posted by 430Scud

Quote:

You can't charge the auxiliary batteries with a charger they only charge when the engine is running via the dedicated management charger and BMW state not to attach a battery charger to them to avoid damaging the dedicated system.

The two studs under the hood don't connect to the auxiliary batteries at all they only go to the starter battery.

So I have learned from another user that it is okay to charge the under hood battery, even though BMW advises it may risk damaging the isolation circuitry. He had been doing if for some time.

I started charging the battery occasionally, leaving my battery tender connected for up to two or three weeks at a time. Been over a year with no repercussions. Note I use a 4amp battery tender....I would not recommend using anything larger amperage, as that may be the reason for the caution from BMW.

For a 530e there isn’t any value to hooking up a battery tender to the car to charge the battery. The HV battery system will automatically charge them as needed.

Name: 12V Battery.jpg
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Name: 12V Battery.jpg
Views: 15499
Size: 191.2 KB

CnSky · 07-27-2021, 06:06 PM

I wonder does it charge only the 12v main starter battery not the auxiliary battery as according to the info I found aux battery is only charged by the engine when running.

I can also no orange HV lines coming to the battery in the trunk but there may be some lines going to the starter

CnSky · 07-27-2021, 07:22 PM

So is anyone able to say 100% that the auxiliary battery is the one I see in the trunk floor on a 530e?

I think it is as I disconnected the one behind the rear tail light yet everything in the cabin idrive lighting etc remains working. There isn't any battery under the hood.

Didn't try start the engine while it was disconnected for fear of the car throwing a CEL and going crazy.

430Scud · 07-27-2021, 09:02 PM

Quote:

Originally Posted by LogicalApex

For a 530e there isn’t any value to hooking up a battery tender to the car to charge the battery. The HV battery system will automatically charge them as needed.

Attachment 2658642

Gotcha, I didn't realize that was a HV battery.

LogicalApex · 07-27-2021, 09:53 PM

Quote:

Originally Posted by CnSky

I wonder does it charge only the 12v main starter battery not the auxiliary battery as according to the info I found aux battery is only charged by the engine when running.

I can also no orange HV lines coming to the battery in the trunk but there may be some lines going to the starter

I would imagine it charges both, but I am not a BMW tech so that is just an assumption on my part. That said, you shouldn’t see orange HV cables going directly to either battery. They will be connected to whatever IBS charging setup BMW out in place. As the HV system is 270V and those batteries are 12V.

Also, keep in mind that the 530e is designed to have the engine run once a year or even less. So it won’t rely on the “engine running” to charge any batteries. That is only an ICE car requirement.

CnSky · 07-28-2021, 08:07 AM

Thank logical I see some red paper cable coming to the IBS for each battery but no orange cable I do wonder why BMW made it so complex for 12v power on these cars.

Anyway as the aux battery is throwing a fault as aged and the VDP is showing a fault as not receiving enough power every now and again along with a few other units I'm changing the battery.

freshxdough · 08-12-2021, 08:31 PM

Quote:

Originally Posted by CnSky

So is anyone able to say 100% that the auxiliary battery is the one I see in the trunk floor on a 530e?

I think it is as I disconnected the one behind the rear tail light yet everything in the cabin idrive lighting etc remains working. There isn't any battery under the hood.

Didn't try start the engine while it was disconnected for fear of the car throwing a CEL and going crazy.

The aux 12v battery is the one in the right side of the trunk behind the panels.

mrjlaunch · 09-16-2022, 12:09 PM

CnSky were you able to locate and change the auxiliary battery?
ISTA+ is telling me the same thing on my 2018 530e and the workshop manual doesn't show exactly where it's located.

Error code is: 218219 Starter unit, charging controller for auxiliary battery: Aged auxiliary battery

CnSky · 09-16-2022, 06:37 PM

Quote:

Originally Posted by mrjlaunch

CnSky were you able to locate and change the auxiliary battery?
ISTA+ is telling me the same thing on my 2018 530e and the workshop manual doesn't show exactly where it's located.

Error code is: [COLOR="Blue"]218219 Starter unit, charging controller for auxiliary battery: Aged auxiliary battery[/COLOR]

Yes it's the one under the floor panel.

It's impossible or at least I found it so to find a correct replacement battery so in the end I just let BMW replace it and it wasn't too bad only 30 Euro more than had I done the work myself with the closest battery match I could find after shipping etc.

SteveinArizona · 09-17-2022, 10:58 AM

When my 2018 530e was in for maintenance toward the end of my 4th year of ownership, the dealership found an exhausted auxiliary battery and changed it as a warranty item. Pleasant surprise to me (they also found a bad cell in the battery pack and replaced the entire battery pack; perhaps the latter caused the former).

Qsilver7 · 09-17-2022, 05:34 PM

Quote:

Originally Posted by CnSky

Yes it's the one under the floor panel.

It's impossible or at least I found it so to find a correct replacement battery so in the end I just let BMW replace it and it wasn't too bad only 30 Euro more than had I done the work myself with the closest battery match I could find after shipping etc.

The smaller 60 AH or 50 AH aux batteries are usually a 97R/H5/LN2 or 140R/H4/LN1 class size battery.

You can see the specs (length/width/height) in the East Penn battery chart below. You can also see the Amp Hour, cold cranking amps, and other battery specs that can help guide you toward the size and capacity you need for replacement.

Once you know which battery class size you need…shop for that info to help find a non BMW branded replacement. In the US DELCO usually sells the smaller H4 & H5 batteries for less than the dealer…but very few places carry them and you may end up ordering them online from places like RockAuto.com.

https://www.rockauto.com/en/moreinfo...=8878472&jsn=7

CnSky · 09-17-2022, 05:37 PM

Wish I was state side I found it impossible to find the proper spec battery in Europe. I'm convinced the OEMs make these strange amp hour batteries just for the manufacturers to make it difficult on the consumer side.

Qsilver7 · 09-17-2022, 05:42 PM

…so true…don’t no why the small aux AGM H4 & H5 batteries are so hard to find.

mrjlaunch · 09-19-2022, 11:35 AM

Quote:

Originally Posted by CnSky

Yes it's the one under the floor panel.

It's impossible or at least I found it so to find a correct replacement battery so in the end I just let BMW replace it and it wasn't too bad only 30 Euro more than had I done the work myself with the closest battery match I could find after shipping etc.

I'm officially confused now...
I connected to the car with ISTA+ and it tells me the Auxiliary Battery is 60Ah model not the 90Ah one

I should mention the following for anyone else looking for replacement batteries. They're easily found searching for the BCI (Battery Council International) group as follows:
For the 60Ah battery search online for "type 27 agm battery" example
For the 90Ah battery search online for "type 19 agm battery" example

07-25-2021, 05:24 PM	#1
CnSky Major 330 Rep 1,028 Posts Drives: BMW 530E 2017 Join Date: Aug 2013 Location: Ireland iTrader: (0)	Aux Battery hide and seek? On the 530E G30 can anyone tell me for sure 100% where the Aux battery is? I know I have one as it needs changing and as I have bimmer code etc I want to do it myself but the manual and other sources seem split between the trunk or the hood. I can see the following but the second photo I beliebv is the motor electonics unit so no battery under the hood. In the back I can only see a single battery where is this Aux battery hiding? Attached Images
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07-25-2021, 05:53 PM	#2
CHECKERED ex deus machina 124 Rep 968 Posts Drives: G30, F15, Audi S4 Join Date: Oct 2012 Location: Southern NH iTrader: (12)	middle of the trunk under some removable sheet metal http://135jik1bbhst1159ri1ax2pj.wpen...xtrication.pdf __________________ Daily: G30 M550i, Bluestone, JB4, 1 step colder plugs, 6WB retrofit Winter Beast: Audi S4 4.2L V8, Supercharger, brakes, suspension & exhaust mods Wifes': F15 M50d clone, DUDMD tune, WMI, MPBK Gone: E92 335i N54 468rwtq
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07-25-2021, 05:56 PM	#3
CnSky Major 330 Rep 1,028 Posts Drives: BMW 530E 2017 Join Date: Aug 2013 Location: Ireland iTrader: (0)	Thanks, wonder how the hell I can access it will try tomorrow.
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07-26-2021, 11:08 AM	#4
CnSky Major 330 Rep 1,028 Posts Drives: BMW 530E 2017 Join Date: Aug 2013 Location: Ireland iTrader: (0)	So is this the additional battery below the trunk floor weird as it's 90ah and the other is only 60 I would've expected it the other way around. Attached Images
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07-27-2021, 02:22 AM	#5
bopjensen New Member 3 Rep 13 Posts Drives: BMW I3 2019, BMW 530D M-Sport Join Date: Jul 2021 Location: Denmark iTrader: (0)	Hi How do you know it needs charging? Can't you just start the car and go for a drive? Front bat is AUX the one in the back is for starting engine. you can charge them by connecting a charger to the two jump start studs in the engine bay left side front and back. Best regards Bo
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07-27-2021, 03:17 AM	#6
CnSky Major 330 Rep 1,028 Posts Drives: BMW 530E 2017 Join Date: Aug 2013 Location: Ireland iTrader: (0)	Bo I have a fault code Aged aux battery when checking with ISTA. The battery is beyond saving when this happens as it's not holding enough voltage. Aux battery no 3 is under the hood on the G31 which powers the air suspension and active rear steering. On the G30 it's definitely one of the two in the trunk as there is none under the hood but I just can't figure out which one it is 100% as even the shop manual isn't clear. You can't charge the auxiliary batteries with a charger they only charge when the engine is running via the dedicated management charger and BMW state not to attach a battery charger to them to avoid damaging the dedicated system. The two studs under the hood don't connect to the auxiliary batteries at all they only go to the starter battery. QUOTE=bopjensen;27849286]Hi How do you know it needs charging? Can't you just start the car and go for a drive? Front bat is AUX the one in the back is for starting engine. you can charge them by connecting a charger to the two jump start studs in the engine bay left side front and back. Best regards Bo[/QUOTE]
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07-27-2021, 07:20 AM	#7
bopjensen New Member 3 Rep 13 Posts Drives: BMW I3 2019, BMW 530D M-Sport Join Date: Jul 2021 Location: Denmark iTrader: (0)	Hi Sorry i misread “changing” as “charging” in your original post 🤭 Best regards Bo
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07-27-2021, 03:42 PM	#8
430Scud Second Lieutenant 253 Rep 295 Posts Drives: M550iX,430 Scud,E39 540Msport Join Date: Mar 2020 Location: Seattle, WA iTrader: (0)	[QUOTE You can't charge the auxiliary batteries with a charger they only charge when the engine is running via the dedicated management charger and BMW state not to attach a battery charger to them to avoid damaging the dedicated system. The two studs under the hood don't connect to the auxiliary batteries at all they only go to the starter battery. [/QUOTE][/QUOTE] So I have learned from another user that it is okay to charge the under hood battery, even though BMW advises it may risk damaging the isolation circuitry. He had been doing if for some time. I started charging the battery occasionally, leaving my battery tender connected for up to two or three weeks at a time. Been over a year with no repercussions. Note I use a 4amp battery tender....I would not recommend using anything larger amperage, as that may be the reason for the caution from BMW.
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07-27-2021, 06:06 PM	#10
CnSky Major 330 Rep 1,028 Posts Drives: BMW 530E 2017 Join Date: Aug 2013 Location: Ireland iTrader: (0)	Aux Battery hide and seek? I wonder does it charge only the 12v main starter battery not the auxiliary battery as according to the info I found aux battery is only charged by the engine when running. I can also no orange HV lines coming to the battery in the trunk but there may be some lines going to the starter
	Appreciate 0 Quote

07-27-2021, 07:22 PM	#11
CnSky Major 330 Rep 1,028 Posts Drives: BMW 530E 2017 Join Date: Aug 2013 Location: Ireland iTrader: (0)	So is anyone able to say 100% that the auxiliary battery is the one I see in the trunk floor on a 530e? I think it is as I disconnected the one behind the rear tail light yet everything in the cabin idrive lighting etc remains working. There isn't any battery under the hood. Didn't try start the engine while it was disconnected for fear of the car throwing a CEL and going crazy.
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07-28-2021, 08:07 AM	#14
CnSky Major 330 Rep 1,028 Posts Drives: BMW 530E 2017 Join Date: Aug 2013 Location: Ireland iTrader: (0)	Thank logical I see some red paper cable coming to the IBS for each battery but no orange cable I do wonder why BMW made it so complex for 12v power on these cars. Anyway as the aux battery is throwing a fault as aged and the VDP is showing a fault as not receiving enough power every now and again along with a few other units I'm changing the battery.
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09-16-2022, 12:09 PM	#16
mrjlaunch New Member 3 Rep 20 Posts Drives: 2018 530e (G30) Join Date: Dec 2021 Location: England iTrader: (0)	CnSky were you able to locate and change the auxiliary battery? ISTA+ is telling me the same thing on my 2018 530e and the workshop manual doesn't show exactly where it's located. Error code is: 218219 Starter unit, charging controller for auxiliary battery: Aged auxiliary battery
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09-17-2022, 10:58 AM	#18
SteveinArizona Brigadier General 3086 Rep 4,210 Posts Drives: BMW 530e Join Date: Jul 2016 Location: Greater Phoenix iTrader: (0)	When my 2018 530e was in for maintenance toward the end of my 4th year of ownership, the dealership found an exhausted auxiliary battery and changed it as a warranty item. Pleasant surprise to me (they also found a bad cell in the battery pack and replaced the entire battery pack; perhaps the latter caused the former).
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09-17-2022, 05:37 PM	#20
CnSky Major 330 Rep 1,028 Posts Drives: BMW 530E 2017 Join Date: Aug 2013 Location: Ireland iTrader: (0)	Wish I was state side I found it impossible to find the proper spec battery in Europe. I'm convinced the OEMs make these strange amp hour batteries just for the manufacturers to make it difficult on the consumer side.
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09-17-2022, 05:42 PM	#21
Qsilver7 Major General 4448 Rep 7,488 Posts Drives: F06 650ix GC / F15 X5 50i Join Date: Oct 2016 Location: Indiana, USA iTrader: (0)	…so true…don’t no why the small aux AGM H4 & H5 batteries are so hard to find. __________________ 2015 F06 650ix Gran Coupe`(Moonstone/Cohiba Brown)\| 2014 F15 X5 50i MSport (Space Gray/Mocha) Become a BMW CCA member! Click HERE to join and feel free to use my BMW CCA member #191509 as a referral.
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