Checking Electrolyte Level; Checking Specific Gravity - Kohler Power Systems 8RESV Service Manual

2.9.1 Checking Electrolyte Level

Check the electrolyte level of batteries with filler caps
monthly. Remove filler caps and verify that electrolyte
level reaches bottom of filler holes. Refill as necessary
with distilled water. DO NOT add fresh electrolyte.
Tighten all filler caps. If water is added during freezing
temperatures, run the generator set for 20--30 minutes
to mix the electrolyte and water to prevent battery
damage from freezing.

2.9.2 Checking Specific Gravity

Use a battery hydrometer to check the specific gravity of
the electrolyte in each battery cell. While holding the
hydrometer vertically, read the number on the glass bulb
at the top of the electrolyte level or the number adjacent
to the pointer. If the hydrometer used does not have a
correction table, use the correction factors in
Figure 2-14. Determine specific gravity and electrolyte
temperature of battery cells. Locate temperature in
Figure 2-14 and adjust the specific gravity by the
amount shown.
The battery is fully charged if the specific gravity is 1.260
at an electrolyte temperature of 80F (26.7C). The
difference between specific gravities of each cell should
not exceed 0.01. Charge the battery if the specific
gravity is below 1.215 at an electrolyte temperature of
80F (26.7C). See Figure 2-12.
Specific Gravity,
80F (26.7C)
Corrected to
Below 1.215
1.260
Figure 2-12 Specific Gravity Interpretation
Some battery testers have four or five beads in the test
tube. Draw electrolyte into the tube as performed with
the battery hydrometer described previously. Use the
manufacturer's instructions.
typical test results.
Number of Floating Beads
5
4
3
1 or 2
0
Figure 2-13 Bead-Type Test Interpretation
26 Section 2 Scheduled Maintenance
Battery
Condition
Needs charging
Fully charged
Figure 2-13 interprets
Battery
Condition
Overcharged
Fully charged
Good charge
Low charge
Dead battery
Temperature
Correction
C F
71.1 160 + .032
+ .030
65.6 150 + .028
+ .026
60.0 140 + .024
+ .022
54.4 130 + .020
+ .018
48.9 120 + .016
+ .014
43.3 110 + .012
+ .010
37.8 100 + .008
+ .006
32.2 90 + .004
+ .002
26.7 80 0
- - .002
21.1 70 - - .004
- -. 006
15.6 60 - - .008
- - .010
10 50 - - .012
- - .014
4.4 40 - - .016
- - .018
- - 1.1 30 - - .020
- - .022
- - 6.7 20 - - .024
- - .026
- - 12.2 10 - - .028
The temperature correction amounts to about .004 (4 points) of
specific gravity for each 10F (5.5C) change in temperature.
Figure 2-14 Specific Gravity Temperature Correction
EXAMPLE NO. 1—
Temperature below 80F (26.7C)
Hydrometer Reading 1.250
Acid Temperature 20F (- -6.7C)
Subtract .024 Specific Gravity
Corrected Specific Gravity is
1.226
1.250 - - .024 = 1.226
EXAMPLE NO. 2—
Temperature above 80F (26.7C)
Hydrometer Reading 1.235
Acid Temperature 100F (37.8C)
Add .008 Specific Gravity
Corrected Specific Gravity is
1.243
1.235 + .008 = 1.243
1-787
TP-6881 7/15