Battery Replacement Questions

[quandary]

I have Carly and have asked them similar questions:

1) Does the AH setting matter?
I'm guessing that they are measuring the time, temperature, and current to see when the battery starts to plateau as it gets low. Assuming the increase from 90AH to 92AH is more than a marketing gimmick...and that the coding actually asks for the AH...there must be some measurement and calculation of used AH to guesstimate the battery condition and/or potential before a voltage drop. (In Carly, i have the option to custom set the battery so i'm asking the question.) If so, wouldn't leaving a default of 90AH result in a premature diagnosis of the battery end-of-life? I've also read in this forum that they might also use it to calculate the charge time, but most BSM's would simply look at the voltage to know when to stop. (Anyone leave it at 90 AH and put in the 105 AH battery?)

2) What does registration of the main battery actually do?
There is clearly a timestamp log recorded. Perhaps it simply resets all other counters associated with the battery life. Anybody know for sure?

3) How does the accessory battery get coded and registered? (This is the one i am most interested about.)
Carly doesn't have this feature and i have asked them about it. I have seen threads that ISTA might do it but not any videos or step-by-step instructions where it is actually performed for the accessory battery.

Thanks, in advance.

[Qsilver7]

1. The AH setting matters when there's a huge difference. Like if you were going from a 90 AH down to an 85 AH...or going from a 92 AH to a 105 AH battery. But going from a 90 AH to 92 AH or vice versa...doesn't matter.

2. See info below that explains battery registration. Do note that there's a DIFFERENCE between battery registration and battery coding. Coding is done to change the specs/parameters of the battery...registration is performed to let the power management system know that a new battery is installed etc.:

3. I don't know how it's done in Carly...but in BimmerCode/BimmerLink...there's a selection for working with the auxiliary battery:

[quandary]

Thanks for the answers.

(1) I guess i will have to do without the precision of the extra 2 AH. I can see that the car estimates the available capacity in the battery. Functionally, it would work the same but lose 2.2% of run-time in my case.

(2) The registration process describes issues related to the power management not working properly. Perhaps my desire to understand to assess the risks is too technical. But my question was what does it actually do other than record a timestamp? Assuming that it knows the date of the change, decisions can be made around how much voltage or over-voltage an alternator can charge towards. As the battery ages, the over-voltage tolerances decrease. So, no registration would likely result in a battery being charged to a lower voltage (12.6V or lower) because it thinks the battery is older, instead of trying to overcharge (13.8V). I guess i am answering my own question but wanted to see if someone else can confirm.

(3) Can you walk me through which menus you navigated? I have both Bimmercode and Bimmerlink as well. Bimmercode doesn't have anything for battery registration as far as i can see. For Bimmerlink, i can only see a single button to register the battery. It only reads the statistics for the main battery, i do no see any option to register the accessory battery.

BTW...I believe the accessory battery is 12V, so i think the reference is incorrectly applied to this battery.

[Chapultepec]

I recently replaced battery on my 2014 35xi with a new 105amp, registered it with ISTA+. Easy process but to my surprise all kind of power management and steering errors afterwards came up. I then had to do a re-adaptation of power management/steering/abs, also with ISTA+, everything went fine, but annoying that this is necessary just to change a battery. And funny to see how the front lifted car turns the wheels by itself during re-adaptation

[Qsilver7]

As mentioned in earlier posts in this thread...there are TWO different things you may need to do depending on what type of replacement battery you install.

If you replace the battery with a like kind battery (same AH) then all you need to do is register the new battery.,

If you replace the battery with one with less AH or more AH...then you will need to CODE the new battery...then register it.

[turboawd]

What would happen (for those of us with 2 batteries) if we didn't replace the small battery and it eventually dies? Will that throw any codes? Leave you stranded?
I'm due for batteries, and don't want to pay $400 for a new one from bmw.

[Qsilver7]

Originally Posted by turboawd

What would happen (for those of us with 2 batteries) if we didn't replace the small battery and it eventually dies? Will that throw any codes? Leave you stranded?
I'm due for batteries, and don't want to pay $400 for a new one from bmw.

The auxiliary batteries...whether the lithium or the smaller AGM...are for operating additional options that require the extra power. If the auxiliary battery dies, is starting to fail, or becomes deeply discharged...then it will probably just affect the features that it powers.

Here’s some info about the charging controller for the auxiliary battery from the TIS website...perhaps it can shed some light on how it helps to keep the aux battery charged: https://www.newtis.info/tisv2/a/en/f...ttery/GH1wlj6L

[quandary]

I now have a chassis stabilization malfunction...drive carefully. This didn't exist before and I have seen some forums suggesting re-calibrating the steering wheel (turning all way to the left, right, the center) which i've tried without success. I have noticed that the longer i wait to start the car, the longer it takes for the malfunction to come up...so maybe it's related to temperature or some capacitor discharge. I'll wait a few hours before i drive again next time. Although it could be unrelated to the battery change, it happened right afterwards. Any assistance is appreciated.

I changed out my batteries with a 92AH and 50AH and used Carly to register the new battery. (No coding to recognize the extra 2AH.) As far as the registration is concerned, all went well and both Carly and Bimmerlink do not have an option for the second battery. I re-read the battery and it shows that battery has been changed with the mileage and all of the battery performance history has been reset to zero. For example, it recorded the number of hours that the battery was at a voltage range e.g. 11-12 volts. So, registration seems to be basically a mileage stamp to reset the counters.

The second battery does not seem to have a power management monitor on the negative terminal like the larger one. Both positives are connected to the power control unit. I'm guessing that registration is only required on the main battery since it is more important to start the engine. If you have ISTA, please let me know if there really is a registration for the "12V" accessory battery and not for connecting a thrid 24V accessory battery.

[CatalinP]

You need ISTA to perform EPS calibration.

[turboawd]

Originally Posted by quandary

I now have a chassis stabilization malfunction...drive carefully. This didn't exist before and I have seen some forums suggesting re-calibrating the steering wheel (turning all way to the left, right, the center) which i've tried without success. I have noticed that the longer i wait to start the car, the longer it takes for the malfunction to come up...so maybe it's related to temperature or some capacitor discharge. I'll wait a few hours before i drive again next time. Although it could be unrelated to the battery change, it happened right afterwards. Any assistance is appreciated.

I changed out my batteries with a 92AH and 50AH and used Carly to register the new battery. (No coding to recognize the extra 2AH.) As far as the registration is concerned, all went well and both Carly and Bimmerlink do not have an option for the second battery. I re-read the battery and it shows that battery has been changed with the mileage and all of the battery performance history has been reset to zero. For example, it recorded the number of hours that the battery was at a voltage range e.g. 11-12 volts. So, registration seems to be basically a mileage stamp to reset the counters.

The second battery does not seem to have a power management monitor on the negative terminal like the larger one. Both positives are connected to the power control unit. I'm guessing that registration is only required on the main battery since it is more important to start the engine. If you have ISTA, please let me know if there really is a registration for the "12V" accessory battery and not for connecting a thrid 24V accessory battery.

Yeah I'd give it some time to see if it just goes away. Where did you buy your batteries?

[quandary]

I bought the batteries from the BMW dealer. Interesting...the problem went away the next day.

[turboawd]

Originally Posted by quandary

I bought the batteries from the BMW dealer. Interesting...the problem went away the next day.

That's good to hear. How much did the batteries cost you each?

[quandary]

I'm in Canada and paid full price...over $900 for the pair. That's $200 USD...lol The trip to the dealership was based on the difficulty in finding the correct form factor in my area.

I also noticed that the battery data read showed a charge percentage on the old battery at 70%. Since the battery module is not actually able to know this, it must be a calculated estimate based on age, miles, and the number of hours below 12 V. (This is probably used to determine what voltage to target as the battery ages.) It now shows 100% after the registration.

On a side note, you can tell the manufactured date of the battery. One battery was stamped with 2015 on the negative terminal. So, the battery is already 5 years old. I'm expecting that it won't last beyond the warranty so i'll have to keep the receipt around until then.

[turboawd]

Originally Posted by quandary

I'm in Canada and paid full price...over $900 for the pair. That's $200 USD...lol The trip to the dealership was based on the difficulty in finding the correct form factor in my area.

I also noticed that the battery data read showed a charge percentage on the old battery at 70%. Since the battery module is not actually able to know this, it must be a calculated estimate based on age, miles, and the number of hours below 12 V. (This is probably used to determine what voltage to target as the battery ages.) It now shows 100% after the registration.

On a side note, you can tell the manufactured date of the battery. One battery was stamped with 2015 on the negative terminal. So, the battery is already 5 years old. I'm expecting that it won't last beyond the warranty so i'll have to keep the receipt around until then.

Ouch. That's expensive. I wish someone would make the smaller battery. My main battery is early 14 and the smaller battery is late 13. I'm shocked it's holding up so long. Especially considering that lately I might not drive it for weeks at a time. I never charge it.