Today’s vehicles are on the forefront of sophisticated technology
in all aspects of drive-ability and performance while reducing price
and unreliability. Manufacturers find it necessary to not only
compete on super elevated platforms for performance and
reliability requirements set by consumers, but also more and more
rigid guidelines for internal combustion efficiency and expulsion
created by local and federal law. Literally ALL of the components
in newer vehicles have been super engineered. The batteries are no
A new type of battery, AGM (absorbent glass mat) has emerged into
the aftermarket, and is slowly becoming integrated by new car
manufacturers. Fiberglass mats are laid out on an open surface and
flooded with acid. Because the acid absorbs efficiently into the
fiberglass mat, it is not necessary to have a wet lead cell. This
of course makes the batteries far less weight cumbersome and not
necessary to ship as hazardous material in many states because
there is no risk of a spill.
These batteries also add to the complexity and requirements of
battery charger manufacturers who elect to supply chargers for
such cars and motorcycles. 14.7 VDC is the recommended charge
voltage for the AGM battery.
THE NEW BMW BATTERY
The BMW new Battery must be registered to the main computer for
the vehicle to Recognize.
As per BMW’s reputation for hi tech design, battery replacement is
no exception. After installing a new battery in BMW’s 5 and 7
series, the battery must be registered with the vehicle PCM to
initiate starting and charging system operation.
This may seem like a classic case of over technology, but in reality, it is based
on the premise that the computer has the desirable ability to
charge an older battery in a different way than it would charge a
new battery. The system also, as in the past, can base amperage
flow decisions on ambient temperature and changing electrical load
BMW calls the main component an IBS (intelligent battery sensor)
which collects data regarding battery state of charge in volts,
battery temperature, and the various amperage’s that are entering
and leaving the battery at any point in time. The IBS then
transmits the information to the DME (digital motor electronics)
or main on board computer. The DME will analyze and decide a
charge rate to be communicated to the alternator.
Voltage regulators in this system are referred to as COM regulators as
they are capable of communicating back to the DME and receiving
information from the DME on what charge rate to apply to the
battery and what voltage is to be maintained.
This is the main reason new battery registration to the DME (on
board computer) is necessary. Naturally, the DME regards different
parameters to communicate to the the voltage regulator on a
vehicle with a new battery, than the parameters set for an older
battery. Batteries, which can be considered to be a legitimate
expense, may be able to possibly achieve 6-7 year life expectancy
as compared to 3-4 year life expectancy, even in adverse climate
and performance arenas.