2B-2 - ELECTRICAL 90-824052R3 JUNE 2002
Battery
Precautions
WARNING
If battery acid comes in contact with skin or eyes,
wash skin immediately with a mild soap. Flush
eyes with water immediately and see a doctor.
When charging batteries, an explosive gas mixture
forms in each cell. Part of this gas escapes through
holes in vent plugs and may form an explosive
atmosphere around battery if ventilation is poor. This
explosive gas may remain in or around battery for
several hours after it has been charged. Sparks or
flames can ignite this gas and cause an internal
explosion which may shatter the battery.
The following precautions should be observed to
prevent an explosion.
1. DO NOT smoke near batteries being charged or
which have been charged very recently.
2. DO NOT break live circuits at terminals of
batteries because a spark usually occurs at the
point where a live circuit is broken. Always be
careful when connecting or disconnecting cable
clamps on chargers. Poor connections are a
common cause of electrical arcs which cause
explosions.
3. DO NOT reverse polarity of battery terminal to
cable connections.
Specific Gravity Readings
Use a hydrometer to measure specific gravity of elec-
trolyte in each cell.
Hydrometer measures percentage of sulfuric acid in
battery electrolyte in terms of specific gravity. As a
battery drops from a charged to a discharged
condition, acid leaves the solution and enters the
plates, causing a decrease in specific gravity of
electrolyte. An indication of concentration of
electrolyte is obtained with a hydrometer.
When using a hydrometer, observe the following
points:
1. Hydrometer must be clean (inside and out) to
insure an accurate reading.
2. Never take hydrometer readings immediately
after water has been added. Water must be
thoroughly mixed with electrolyte by charging for
at least 15 minutes at a rate high enough to cause
vigorous gassing.
3. If hydrometer has built-in thermometer, draw
liquid in several times to ensure correct
temperature before taking reading.
4. Hold hydrometer vertically and draw in just
enough liquid from battery cell so that float is
free-floating. Hold hydrometer at eye level so that
float is vertical and free of outer tube, then take
reading at surface of liquid. Disregard curvature
where liquid rises against float stem due to
capillarity.
22532
5. Avoid dropping electrolyte on boat or clothing, as
it is extremely corrosive. Wash off immediately
with baking soda solution.
Specific gravity of electrolyte varies not only with
percentage of acid in liquid but also with temperature.
As temperature increases, electrolyte expands, so
that specific gravity is reduced. As temperature
drops, electrolyte contracts, so that specific gravity
increases. Unless these variations in specific gravity
are taken into account, specific gravity obtained by
hydrometer may not give a true indication of acid in
electrolyte.
To Next Page
Loading...
Need help?
General
