If a battery now needs to be replaced, it needs to be reprogrammed into the vehicles energy management system. Why is this important? An aged worn out battery shows a different behaviour with regards to available capacity, energy output and charge acceptance then a new unused one. The Battery Management System (BMS) together with the Electronic Battery Sensor (EBS) monitors the battery over its lifetime. It detects e.g. the number of starts and the energy flow (Ah throughput), monitors the state of charge, controls the charging and adapts the energy management of the battery over the time dependent of its state of health.
If the reprogramming is not carried out correctly it can cause restriction or even failure of the start-stop function, which can result in increased fuel consumption and restriction of comfort functions.
Different ways of battery coding
Nowadays we can see in the market that OE car manufacturer follow different strategies to reprogram new batteries in their vehicles BMS.
SELF LEARNING: As a first group there are self-learning systems. Here the BMS comes with only one or a few preprogramed battery options per vehicle which the BMS will use as a reference. After battery replacement the BMS compares over the time the actual new battery performance with the battery references stored in the BMS memory and will learn which of the stored references fits to the actual measured performance. OEs following this strategy are for instance Abarth, Alfa Romeo, Chevrolet (Daewoo), Citroen, Dacia, Fiat, Honda, Lancia, Mercedes, Mitsubishi, Peugeot, Renault, Subaru, Suzuki, Toyota and Volvo.
REGISTRATION WITH DIAGNOSTIC TOOL: A second group of OE car manufacturer require an active registration of the new replacement battery into the vehicles BMS and with it the use of a diagnostic device for reprogramming. Just to give some examples we can name Alpina, Audi, BMW, Jaguar, Jeep, Land Rover, Mazda, Mini, Seat, Skoda and Volkswagen. And within this group some vehicle manufacturers like the VAG group or BMW require a code to register the new battery during replacement. The codes are not only OE but also battery specific.
The VAG specific BEM code is basically a two line code. The first line contains the OE spare part number. This number is different for OES (i.e. 000915105DG) and OEM (i.e. 4F0915105E) channel but limited to the amount of battery types VAG uses. The second line codes the battery manufacturer, the manufacturing date of the battery and contains a part making this code specific.