technical keeping car connected to booster pack when changing the battery instead of coding?

MLorgat

Member
As per the title, every battery centre I've asked thus far has said that they don't do coding when changing batteries, but instead plug in booster packs so the ECU doesn't lose its memory and the car will eventually adapt???

Any experience with this?
 

Clint@MMS AUTO

BMWFanatics Advertiser
Official Advertiser
BMW (and most modern German cars) require battery registration when you replace the battery because of how the intelligent battery management system (IBS) works. Let me break it down simply:



1. BMWs “talk” to the battery
Modern BMWs use an IBS module to monitor the battery’s:
  • Charge level (State of Charge – SoC)
  • Health (State of Health – SoH)
  • Age and capacity (Amp-hours & type)
  • Charging cycles, temperature, and even how it’s being used.
The car adjusts how the alternator charges the battery over its lifetime. Older batteries get a more aggressive charge to compensate for wear.


⚠️ 2. What happens if you don’t register?
If you fit a new battery but don’t tell the car:
  • It thinks the old, worn-out battery is still in place.
  • The charging system may undercharge (leading to a flat battery) or overcharge (shortening the new battery’s life).
  • This can also cause electrical errors, start/stop issues, and early failure of the new battery.


🔑 3. What does “registration” actually do?
When you register a new battery with a BMW diagnostic tool (like ISTA, iCarsoft, Autel, etc.), the car:
  • Resets its battery age and charge history.
  • Adapts the alternator charging strategy for the new battery.
  • Records the new battery type (AGM or lead-acid) and capacity (e.g. 80Ah, 90Ah).
This keeps the IBS working properly and maximizes the new battery’s life.


📌 Extra Note:
If you change to a battery with a different capacity (e.g. 70Ah → 90Ah) or different type (lead-acid → AGM), you also need to code the new specifications into the car – not just register.
 

QikNish

Well-known member
BMW (and most modern German cars) require battery registration when you replace the battery because of how the intelligent battery management system (IBS) works. Let me break it down simply:



1. BMWs “talk” to the battery
Modern BMWs use an IBS module to monitor the battery’s:
  • Charge level (State of Charge – SoC)
  • Health (State of Health – SoH)
  • Age and capacity (Amp-hours & type)
  • Charging cycles, temperature, and even how it’s being used.
The car adjusts how the alternator charges the battery over its lifetime. Older batteries get a more aggressive charge to compensate for wear.


⚠️ 2. What happens if you don’t register?
If you fit a new battery but don’t tell the car:
  • It thinks the old, worn-out battery is still in place.
  • The charging system may undercharge (leading to a flat battery) or overcharge (shortening the new battery’s life).
  • This can also cause electrical errors, start/stop issues, and early failure of the new battery.


🔑 3. What does “registration” actually do?
When you register a new battery with a BMW diagnostic tool (like ISTA, iCarsoft, Autel, etc.), the car:
  • Resets its battery age and charge history.
  • Adapts the alternator charging strategy for the new battery.
  • Records the new battery type (AGM or lead-acid) and capacity (e.g. 80Ah, 90Ah).
This keeps the IBS working properly and maximizes the new battery’s life.


📌 Extra Note:
If you change to a battery with a different capacity (e.g. 70Ah → 90Ah) or different type (lead-acid → AGM), you also need to code the new specifications into the car – not just register.
ChatGPT FTW 😁
 

Kyle

///Member
As per the title, every battery centre I've asked thus far has said that they don't do coding when changing batteries, but instead plug in booster packs so the ECU doesn't lose its memory and the car will eventually adapt???

Any experience with this?
This is just another example how how scary the 'knowledge' or lack thereof is locally... Friend of mine went through the same process recently and got the same answers.
 

gerald5ive

Member
As my battery aged, the car automatically disabled the auto start/stop. After I put in a new battery and coded it, the start/stop started working again. I can assist with coding the battery if you in jhb.
 

Manfred

Member
As per the title, every battery centre I've asked thus far has said that they don't do coding when changing batteries, but instead plug in booster packs so the ECU doesn't lose its memory and the car will eventually adapt???

Any experience with this?
You must use ISTA to code new battery!
 
Top