Monaco Executive 2001, Owner'S Manual

Page: 152 / 269

Electrical Systems
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5 • 1 5 2
EXECUTIVE
WARNING: Liquid lead acid batteries produce hydrogen gas
while being charged. This is highly explosive. Do not smoke
around batteries. Extinguish all flames in the area. Batteries
may explode resulting in fire, personal injury, property
damage or death.
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The only way to test a battery’s electrolyte solution is with a
hydrometer. Many styles are available, from types with cylinder
graduation (shown here) to types with floating balls. Hydrometers can
be purchased from most auto parts stores. The hydrometer tests the bat-
tery’s electrolyte solution which is measured in specific gravity (sulfuric
acid to water ratio). Distilled water has a specific assigned gravity of
1,000. The hydrometer is calibrated to this mark. Pure sulfuric acid has
a specific gravity reading of 1,840. The acid is 1.84 times heavier than
water. The electrolyte solution is about 64 percent water to 36 percent
acid (fully charged battery). Hydrometer’s with cylinder graduation are
graphed and the exact state of specific gravity can be determined.
Temperature and recent battery activity (charging or discharging)
affect the hydrometer readings. It is best to check the battery when it has
been “at rest” for at least three hours, although readings taken at other
times will give a “ball park” figure. Using the hydrometer, draw the
electrolyte solution up into the tube. Allow the hydrometer to attain the
same temperature as the electrolyte solution. Note the reading for that
cell. Complete the same test for the rest of the cells on that battery bank.
Chart readings are taken at 80° Fahrenheit. Temperature affects
the hydrometer readings. The higher the electrolyte temperature, the
higher the specific gravity reading. The lower the temperature, the lower
the specific gravity reading will be. Add or subtract four points for each
10° variance from the 80° Fahrenheit chart. Readings between cells
should not vary more than 50 points.
If one cell in a particular battery bank being tested is at a 50% state
of charge while the others are fully charged, charge that battery to see if
the low cell will come up. At the same time, do not over charge the
“healthy” cells.
If the low cell does not come up after charging, this battery can dam-
age the rest of the battery bank and should be replaced. An
accurate digital volt meter + - .5% will also give an indicator of the bat-
tery’s state of charge.
Another test that can be performed is to put the battery(s) under a
specified load for a predetermined length of time for that particular bat-
tery’s rating. This machine is usually an adjustable carbon pile that can
vary the load applied to the battery(s) while monitoring voltage to see if
they will perform to the specific rated capacities
Testing the Battery
Temperature Correction Chart.
71.1
65.6
60.0
54.4
48.9
43.3
37.6
32.2
26.7
21.1
15.6
10
4.4
-1.1
-6.7
-12.2
160
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
+32
+30
+26
+25
+24
+22
+20
+18
+16
+14
+12
+10
+ 8
+ 6
+ 4
+ 2
0
- 2
- 4
- 6
- 8
- 10
- 12
- 14
- 16
- 18
- 20
- 22
- 24
- 26
- 28
°C °F Correction
Factor
Hydrometer (Cylinder Type).