Battery Monitor Unit - J367 Adaptation

[Johntheo1]

So, also not a good idea to replace a failed battery with a used one permanently then.

You might have a look sometime at my "2019 Battery Adaptation" post in the MK10 etc Topics and comment on why I am seeing two battery adaptations.

That is what I actually did, originally. Bought a used battery for £15 as opposed to the crazy costs of a new one, and just changed the serial number and other details.

I mean it's been working, but I have got a stop start error that crops up sometimes, unsure if this is linked to the battery, but that's the reason I've bought the new sensor, as it seems to be linked to that according to the fault codes I get.

You have VCDS so go to advanced meas blocks in the can gateway and save and print out the folowing parameters, this will give you some idea of what the BMS is seeing and influencing the fault codes or/and any start/stop problems. You may not be able to see the last parameter, IDE08347 adapted battery capacity 84 Ah, but it doesn't really matter.


IDE01834 Battery voltage 12.172 V
IDE01836 Battery current -4.958 A
IDE01837 Temperature of battery sensor 26 °C
IDE01839 Battery charge status 74 %
IDE01841 Battery internal resistance 7.6 mOhm
IDE01842 Usable battery charge 29 Ah
IDE01843 Battery voltage at rest 12.4 V
IDE01948 Battery internal resistance not normed 6.4 mOhm
IDE07681-MAS06086 Battery total charging throughput-Total re-charge 4228.4 Ah
IDE07681-MAS06087 Battery total charging throughput-Entire energy throughput 4413.9 Ah
IDE03256-MAS06105 Battery adaptation-Rated battery capacity 59 Ah
IDE03256-MAS06106 Battery adaptation-Battery technology EFB
IDE03256-MAS06107 Battery adaptation-Battery manufacturer JCB
IDE03256-MAS06108 Battery adaptation-Battery Serial Number 1111111111
IDE08347 adapted battery capacity 84 Ah

[ciclo]

The IDE03256 block represents the manual configuration field (the data you enter when making a change), while IDE08347 represents the estimated operating value, which the car calculates independently.

If the current battery is not rated at 59 Ah, you must update the IDE03256 channels... for instance, by changing at least one digit of the serial number... so that the car registers the change and resets its learning algorithms.

IDE03256-MAS06105 Battery adaptation-Rated battery capacity 59 Ah.
A fixed value, serving simply as a "base map" to determine the charging technology and theoretical limits of the battery currently installed.

IDE08347 adapted battery capacity 84 Ah.
This parameter is dynamic. It is not a manual setting, but rather the current, adapted capacity calculated by the battery management system (BMS) algorithm after analyzing charge and discharge cycles as well as internal resistance over time.


Why does it show 84 Ah if the original battery is 59 Ah?
1. The physical battery was replaced but not coded correctly.
If the previous owner installed a larger battery (for example, a 70 Ah or 80 Ah AGM or EFB battery) but left the original 59 Ah coding in channels IDE03256, the car has effectively "learned" on its own that the actual battery has a much higher capacity than what is recorded in the system.
2. A glitch or miscalibrated algorithm.
If the battery currently installed is still physically a 59 Ah unit, the car’s algorithm may have skewed the nominal capacity calculation... either due to the battery’s age or because parameters were modified without resetting the serial number.