After using Carly to code my new battery, INPA does indeed confirm (see appendix D) the charging system is using a 36ah AGM charging map, or at least INPA recognizes that’s what Carly set it to. Even though the lowest setting I found in the CAS module was 80ah AGM, Carly provided a 36ah AGM option. I ended up using Carly to code my battery again. Or, maybe the additional options are only available in the CAS module for higher end models like 335is E92’s? I can only speculate as to why some people have more settings available than others.
I believe updating to a newer CAS ZB software may provide more options. There are people that have reported seeing options in the CAS module for as low as 40ah AGM. Therefore, this is what I chose when I coded my car (initially). My 2011 E82 did not have a charging map listed in the CAS module for anything less than 80ah AGM. Both these batteries crank the car strong, but I would not recommend ever using anything weaker! The Deka ETX-30L is rated 400CCA 28.6Ah(20HR) and is a 21lb AGM type battery. I used XS Power 586 Tall Brass Post Adaptors (M6 Thread). Personally, I am running a Deka/East Penn Sports Power ETX-30L Battery ($103.99). Consequently, you may negatively impact the life expectancy of the new battery by coding say an 80ah AGM charging map when your lightweight battery has a discharge capacity of only 18ah… Most important is ensuring you’ve changed the settings from wet-cell to AGM type, if necessary. Code your car for the setting that best matches your new battery. Is this ok?Ī: While not ideal, you can certainly use your new battery. Q: I bought a lightweight battery, but the “ah” rating for my new battery is less than the lowest setting available in the CAS/NFRM module. You must specify to the DME what the “ah” rating of your battery is so the car can run the proper charging algorithm. Moving between these two types without coding can lead to over-charging or under-charging.Īlso, batteries have a discharge rating called amp hours (ah). However, if you switch from a wet-cell type battery to an AGM type battery, or vice versa, you must code for the change.ĪGM and wet-cell batteries require a different rate of charge output from the alternator.
You may not have to! That is, so long as you replace your old battery with an exact replacement. Q: Why do I need to "code" for a new battery?Ī: The answer to this varies. This would be accompanied by a check control warning of excessive battery discharge.” Also, when the IBS sees that battery voltage is too low for normal vehicle operation it can start shutting down vehicle functions to conserve power while keeping the vehicle operational.
The registration process takes place in the ECU, which is the main player in this system. Therefore, at battery replacement time, if you don't tell the ECU it has a new battery it will overcharge the new battery causing it to wear out faster.
The IBS reads this and the ECU tells the charging system to increase voltage and amperage output incrementally as the battery matures. A battery deteriorates normally over time and depending upon service demands and driving profile. The ECU uses this information to control how much charging voltage is needed from the alternator to support vehicle electricity needs. The IBS measures the state of battery charge and sends this information to the ECU. The long answer: " The negative battery cable has an electronic control unit on the battery end of it called an intelligent battery sensor (IBS). Registering a new battery resets the algorithm back to optimal charging voltage for the specified battery. Q: Why do I need to register a new battery?Ī: The short answer is that BMW designed the charging system with an algorithm that varies the rate of charge by the age and type of the battery installed. Over time, improper charging may have detrimental effects on the lifespan of your cars battery and the operation of the vehicles electronics. Q: I replaced my battery and it works just fine, why all the fuss?Ī: Disregarding the need to register and code for a new battery may result in improper charging. Registration and coding will not be successful on older vehicles that are equipped with basic power management systems. Q: I have an older E90, does this apply to me?Ī: This guide only applies to vehicles equipped with IBS (intelligent battery sensor). Please like and share if this guide helps you out! Why pay a dealer or an indie $70-200+ to register your new battery? Continue reading if you’d like to know why it’s important and how you can get it done yourself!