Some gassing will occur while you are filling the battery  due  to  the  release  of  carbon  dioxide  that  is  a product of the drying process of the hydrogen sulfide produced by the presence of free sulfur. Therefore, the filling  operations  should  be  in  a  well-ventilated  area. These gases and odors are normal and are no cause for alarm. P a r t s P a r t s P a r t s P a r t s o   f o  f o   f o   f W a t e r A c i d W a t e r A c i d Approximately 5 minutes after adding electrolyte, the   battery   should   be   checked   for   voltage   and electrolyte strength. More than 6 volts or more than 12 volts, depending upon the rated voltage of the battery, indicates the battery is ready for service. From 5 to 6 volts or from 10 to 12 volts indicate oxidized negative plates,  and  the  battery  should  be  charged  before  use. Less than 5 or less than 10 volts, depending upon the rated voltage, indicates a bad battery, which should not be placed in service. If,   before   placing   the   battery   in   service,   the specific gravity, when corrected to 80°F, is more than .030 points lower than it was at the time of initial filling or  if  one  or  more  cells  gas  violently  after  adding  the electrolyte, the battery should be fully charged before use.   If   the   electrolyte   reading   fails   to   rise   during charging,  discard  the  battery. Most shops receive ready-mixed electrolyte. Some units may still get concentrated sulfuric acid that must be mixed with distilled water to get the proper specific gravity for electrolyte. MIXING  ELECTROLYTE  is  a  dangerous  job. You have probably seen holes appear in a uniform for no apparent reason. Later you remembered replacing a storage  battery  and  having  carelessly  brushed  against the battery. WARNING When   mixing   electrolyte,   you   are handling  pure  sulfuric  acid,  which  can  burn clothing quickly and severely bum your hands and   face.   Always   wear   rubber   gloves,   an apron, goggles, and a face shield for protection against splashes or accidental spilling. When  you  are  mixing  electrolyte,  NEVER  POUR WATER  INTO  THE  ACID.  ALWAYS  POUR  ACID INTO  WATER.  If  water  is  added  to  concentrated sulfuric acid, the mixture may explode or splatter and cause severe burns. Pour the acid into the water slowly, stirring  gently  but  thoroughly  all  the  time.  Large quantities of acid may require hours of safe dilution. Figure 2-5 shows you how much water and acid to mix   for   obtaining   a   certain   specific   gravity.   For example,  mixing  5  parts  of  water  to  2  parts  of  acid produces  an  electrolyte  of  1.300,  when  starting  with 1.835 specific gravity acid. If you use 1.400 specific gravity acid, 2 parts water and 5 parts acid will give the same  results. Let   the   mixed   electrolyte   cool   down   to   room temperature  before  adding  it  to  the  battery  cells.  Hot electrolyte will eat up the cell plates rapidly. To be on the   safe  side,  do  not  add  the  electrolyte  if  its temperature   is  above  90°F.  After  filling  the  battery cells, let the electrolyte cool again because more heat is generated by its contact with the battery plates. Next, take  hydrometer  readings.  The  specific  gravity  of  the electrolyte will correspond quite closely to the values on the mixing chart if the parts of water and acid are mixed  correctly. Battery Maintenance If a battery is not properly maintained, its service life  will  be  drastically  reduced.  Battery  maintenance should   be  done  during  every  PM  cycle.  Complete battery maintenance includes the following: Visually checking the battery. Checking   the   electrolyte   level   in   cells   on batteries   with   caps.   Adding   water   if   the electrolyte level is low. Cleaning  off  corrosion  around  the  battery  and battery   terminals. Specific Gravity Desired Using   1.835 u s i n g    1 . 4 0 0 Sp.   Gr.   Acid Sp.   Gr.   Acid 1.400 3 2 -- 1.345 1 1 1.300 2 5 2 2 1.290 8 3 9 1.275 11 4 11 1.250 13 4 3 1.225 11 3 1 1.200 13 3 13 Figure 2-5.—Electrolyte mixing chart. -- 7 5 2 0 2 0 4 1 10 CM82F158 2-7