Where
to start when discussing a system?
All
systems are made up of interrelated parts and it is usually
difficult to relate to one part without considering the relationship
to the others. For this reason it is often best to take an overview
and then to gradually spiral downward into the relationships.
I will try to proceed so in this and subsequent articles. However,
as always, I ask that you
consider that this is written with the intent to be of service
and without proof reading.
The
typical motorcycle uses a 12-volt, lead-acid battery to provide
electrical power when the bike's charging system is unable to
provide sufficient power. The battery is of limited size and
thus capacity due to weight and size constraints. Some bikes
use a 6-volt rather than a 12 volt battery so perhaps a good
beginning is to consider the difference in appearance and basic
construction.
When
viewed from above, a typical lead-acid battery will have a series
of cell caps or plugs, which were used to fill the battery with
the sulphuric acid (H2SO4) and water mixture called electrolyte.
Each cell of a lead-acid battery (subsequently to be referred
to simply as the battery) has a fully-charged voltage of about
2.1 volts. From this it can easily recognized that 2.1 volts
times six cell caps = 12.6 volts. A six-volt battery will have
three caps. Automotive batteries typically have their cell caps
connected in threes but it is easy to recognize them by the
shape of the caps and a sneak peek to the side of many will
reveal three tubes from each long cap. Viewed
from the side, the three cell walls can often be identified
and usually individual cell plates and dividers within each
cell.
Batteries
require some means to prevent pressure building up inside the
case due to heating and gasses that are produced by electrolysis.
Automotive batteries usually provide venting through baffles
in the cell caps. Due to the shaking, bouncing and tilting to
which bike batteries are subjected, internal baffles are provided
and a single vent tube is provided. This tube is typically connected
to a drain hose which directs spilled electrolyte and corrosive
gasses away from the bike.
One
check that should be on everyone's list is to check the vent
hose! The hose should be firmly in place on the battery's vent
outlet tube, free of kinks, bends and other restrictions, and
directed below the bike where any nasties will not land on expensive
components.
What is 12 volt?
How is battery capacity indicated?
Positive and negative...
More in subsequent articles.
Norm