astroboy;496589 said:
However, DIY the battery replacement is the tricky part with these newer generation BMW. U need to register the battery with the "On Board Computer" a.k.a OBC failing to do this will ..... *forget what will happen..
let me fill in tht 4 u astroboy. battery registration is basically is done as a record on how many times has d car changed battery. for newer models, u can also set the battery current capabilities (Ah) in it via GT1, which makes it easier for u 2 upgrade ur battery current capabilities. this is usually done 4 owners tht usually uses alot of batt power (upgraded sound sys, in-car entertainment, accesories, lightings etc). earlier model still needs d SSS to program d vehicle if u do change batteries with diffrent current capabilities.
so d answer for the blank above is, the car will get confuse with the main power supply and can cause
1) battery warning light ON due to low/high current load
2) battery to flat out/damage faster due to alternator charging is not suitable
3) current leak, ECU damage or high battery discharge might also happen but this is only on a very rare occasion
4) *car will go on power saving mode and degrading some of d car's sys ability(infotainment sys not func at 100%, A/C affected,idling speed increases) to work 100% well due to battery is undercharge. basically this will make ur UDM abit uncomfortable to drive w/o neglecting safety issues (DSC, AFS, LM, Airbag not affected)
* only applies for UDM with an Intelligent Battery Sensor (IBS)