Varta AGM car battery is chosen by BMW for New Mini
1Dec06
BMW are about to fit the new Varta AGM car battery as
original equipment to their New Mini to meet the
increased electrical demands of this vehicle. The AGM
(absorbent glass mat) car battery is a relatively new
type of sealed construction battery that uses saturated
absorbent glass (boron silicate) mats between the plates
instead of a gelled or liquid acid electrolyte. The AGM
car battery is more expensive than the acid filled type
but has distinct advantages.
The acid electrolyte in an AGM car battery is contained
in a series of glass mats. This eliminates spillage,
even if the battery casing is damaged. This type of car
battery is therefore safer in use and of less potential
damage to the environment. (A very positive feature as
far as the etyres green policy is concerned.) Each AGM
car battery is therefore less expensive to move from the
factory to our mobile battery fitting branches. This
somewhat offsets the much higher basic cost.
Additionally, because an AGM car battery does not
contain liquid there is no chance of problems resulting
from freezing or liquid expansion.
AGM batteries are termed recombinant. This describes the
design technology in which the oxygen and hydrogen
recombine inside the car battery. Recombinant batteries
use gas phase transfer of oxygen to the negative plates
to enable recombination back into water while charging.
This prevents water loss through electrolysis. This
recombining has an efficiency of more than 99%..
The charging voltage of this type of car battery is the
same as for a standard car battery. This eliminates the
need for any special adjustments and problems with
incompatible chargers or charging controls. The internal
resistance of an AGM car battery is extremely low. This
almost completely eliminates heating of the car battery
even under heavy charge and discharge currents.
An AGM car battery has a very low standing discharge
rate of approximately 1% to 3% per month. As a result
storage for much longer periods is achieved without the
need for the periodic re-charging that is required by a
standard car battery.
The hydrogen emission of an AGM car battery, even under
severe overcharge conditions, is far below the 4%
maximum specified for aircraft and enclosed space
situations. The plates in an AGM car battery are tightly
packed and rigidly mounted, and will withstand shock and
vibration better than a standard car battery.
The downside is that AGM technology costs up to three
times as much as for a traditional, acid filled car
battery, of the same capacity. It is assumed that as the
AGM car battery becomes more widely fitted as standard
equipment prices will reduce. We assume that this will
be made possible by longer production runs and increased
amortisation of development costs.
The AGM car battery provides a useful upgrade option for
any vehicle that has retro-fitted electrical equipment.
etyres is frequently asked to advise on increasing the
specification for large 4x4s and MPVs where in-car
entertainment for rear seat passengers has been added.
The BMW decision is based on the fact that the original
car battery specification from about 1990 called for
approximately 950 watts of power but this is has now
increased to almost 3500 watts. The huge jump is because
a car battery now has to cope with electronic engine
management, ABS, air bags, a/c, electrically heated
seats DVDs and satellite navigation. It is therefore
essential that any vehicle that is fitted with an AGM
car battery as standard should only have this type of
car battery fitted as a replacement. |
