squeeze the rubber bulb, insert the nozzle into the electrolyte in the cell, and release the bulb. The electrolyte will be sucked
up into the barrel or container allowing the float to ride freely. Start with the cell that is closest to the POSITIVE (+)
terminal.
4. Tap the hydrometer to dislodge any air bubbles on the float.
5. Squeeze the rubber bulb to release the electrolyte back into the battery tester’s cell.
6. To increase the accuracy of the measurement, in the same cell, repeat this process several times so the float will reach the
same temperature as the electrolyte. If you are measuring a large battery tester, stratification can occur when the more concentrated
electrolyte settles to the bottom. If you notice a difference in the readings between the top and bottom of the cell, average the
two readings.
7. At eye level and with the float steady,
battery tester
, read the Specific Gravity at the point the surface of the electrolyte crosses the float
markings. The Specific Gravity reading should be between 1.100 and 1.300.
8. Release the electrolyte back into the cell from which it was taken and record the reading. Be sure to avoid spillage.
9. If the hydrometer is not temperature compensating, measure the electrolyte temperature. If the electrolyte temperature is not
80° F (26.7° C), then adjust the reading using the Temperature Compensation Table and examples in Section 4.4 and determine the
State-of-Charge from the SoC Table. If the hydrometer is temperature compensating, determine the State-of-Charge directly from the
SoC Table.
10. Repeat the process for each individual cell. The Specific Gravity reading should not have a difference of more that 30
"points" (.030) between the lowest and highest reading or 10 "points" (.010) below the battery tester manufacturer’s recommended
temperature value with the battery tester fully charged. If so, try and equalize the the battery tester by following the battery tester manufacturer’s
procedures or the procedure in Section 9. If equalizing does not help, replace the battery tester. You can determine the battery tester’s
State-of-Charge by taking the average of the temperature compensated cell readings, but the battery tester’s performance will be based on
the weakest cell.
11. Throughly rinse the hydrometer with water after using it.
If the battery tester’s electrolyte is above 125° F (51.5° C), allow it to cool. To determine the battery tester’s SoC with the battery tester’s
electrolyte temperature at 80° F (26.7° C), please use the one of the following tables depending on battery tester type. The Low
Maintenance and Standard battery tester SoC table has a baseline that assumes that a 1.265 Specific Gravity (SG) and 12.65 Open Circuit
Voltage (OCV) reading is a fully charged (100%), wet, Low Maintenance (Sb/Ca) or Standard (Sb/Sb) lead-acid battery tester at rest and
with an open circuit (no external current running through it and the negative battery tester cable disconnected). The Maintenance Free
and VRLA battery tester SoC table has a baseline that assumes that a 12.8 Open Circuit Voltage (OCV) reading is a fully charged (100%),
Valve Regulated (AGM or Gel Cell) Lead-Acid (VRLA) battery tester at rest and with an open circuit (no external current running through
it and the negative battery tester cable disconnected). For electrolyte temperatures other than 80° F (26.7° C), please use the
Temperature Compensation table below to adjust the Open Circuit Voltage (OCV) or Specific Gravity readings. The Specific Gravity
or OCV readings for a battery tester at 100% SoC will vary by plate chemistry, so check the battery tester manufacturer’s specifications for
their State-of-Charge definitions for your battery tester. If you do not know the baseline for your battery tester at 100% SoC, please see
Section 9.5. How Do I Know When My battery tester Is Fully Charged? A fully charged wet battery tester at 80° F (26.7° C), can range from
1.215 to 1.300 Specific Gravity (12.22 to 13.00 VDC) and a sealed VRLA Gel Cell or AGM battery tester from 1.285 to 1.310 (12.85 to 13.1
VDC).
LOW MAINTENANCE (Sb/Ca) AND STANDARD (Sb/Sb)
battery tester STATE-OF-CHARGE (SoC)
Digital Voltmeter Open Circuit Voltage at Rest
Approximate State-of-Charge at 80°F (26.7°C)
Approximate Depth-of-Discharge at 80°
F (26.7°C)
Hydrometer Average Cell Specific Gravity
Approximate Electrolyte Freeze Point
12.65
100%
0%
1.265
-77°F
(-67°C)
12.45
75%
25%
1.225
-35°F
(-37°C)
12.24
50%
50%
1.190
-10°F
(-23°C)
12.06
25%
75%
1.155
15°F
(-9°C)
11.89 or less
DISCHARGED
100%
1.120 or less
20°F
(-7°C)[Source: BCI]
MAINTENANCE FREE (Ca/Ca) AND VRLA
battery tester STATE-OF-CHARGE (SoC)
Digital Voltmeter Open Circuit Voltage at Rest
Approximate State-of-Charge at 80°F (26.7°C)
Approximate Depth-of-Discharge at 80°
F (26.7°C)
12.8
100%
0%
12.6
75%
25%
12.4
50%
50%
12.0
25%
75%
11.8 or less
DISCHARGED
100%
STATE-OF-CHARGE (SoC)
TEMPERATURE COMPENSATION
Electrolyte Temperature Degrees Fahrenheit
Electrolyte Temperature Degrees Celsius
Add to Hydrometer’s SG Reading
Add to Digital
Voltmeter’s Reading
120°
48.9°
+.016
-.013
110°
43.3°
+.012
-.011
100°
37.8°
+.008
-.008
90°
32.2°
+.004
-.005
80°
26.7°
0
0
70°
21.1°
-.004
+.007
60°
15.6°
-.008
+.016
50°
10°
-.012
+.028
40°
4.4°
-.016
+.044
30°
-1.1°
-.020
+.062
20°
-6.7°
-.024
+.084
10°
-12.2°
-.028
+.108
0°
–
17.8°
-.032
+.134
Electrolyte temperature compensation, depending on the battery tester manufacturer’s definition of 100% State-of-Charge, will vary. If
you are using a digital DC voltmeter or a non-temperature compensated HYDROMETER, make the adjustments indicated in the table
above. Please note that some battery tester manufacturers express their SoC definitions at 77° F (25° C), and some slight temperature
compensation should occur to normalize the definitions at 80° F (26.7° C) to use the tables above. For example, if the
electrolyte is at 80° F (26.7° C), and the specific gravity reading is 1.265 for a 100% SoC, when the electrolyte is at 20° F
(-6.7° C), the actual specific gravity reading would be 1.289 for a 100% State-of-Charge because the liquid is more dense.
However, when you subtract .024 from 1.289, the corrected reading would be 1.265 or 100% State-of-Charge. At 100° F (37.8° C),
the actual specific gravity reading would be 1.257 for 100% SoC, but the compensated reading, after .008 is added,
battery load tester
, would be 1.265
for 100% State-of-Charge. This is why using a temperature compensated hydrometer is highly recommended and more accurate.
If you are using an accurate (.5% or better) DIGITAL DC VOLTMETER, make the adjustments indicated in the table above. For example,
if the electrolyte is at 80° F (26.7° C), and the voltage reading is 12.65 for a 100% State-of-Charge, when the electrolyte is
at 20° F (-6.7° C),
car battery tester
, the actual voltage reading would be 12.566 for a 100% State-of-Charge. Before you correct the reading by
adding .0843 volts (84.3 millivolts). At 100° F (37.8° C), the actual voltage reading would be 12.658 for 100% SoC.
For wet non-sealed batteries, please check the specific gravity in each cell with a hydrometer and average cells readings. For
sealed batteries, measure the Open Circuit Voltage (OCV) across the battery tester terminals with an accurate (.5% or better) digital DC
voltmeter. This is the only way you can determine the battery tester’s SoC. Some sealed wet batteries have a built-in hydrometer, "Magic
Eye", which only measures the State-of-Charge in ONE of its six cells.
"Magic Eye" Built-in Hydrometer
[Source: Popular Mechanics]
If the State-of-Charge is BELOW 75% using either the Specific Gravity, voltage test or the built-in hydrometer does not indicate
"good" (green or blue), then the battery tester has a low charge and needs to be recharged before proceeding. If the battery tester is sealed,
the battery tester could have low electrolyte, especially in a hot climate. You should replace the battery tester, if one of the following
conditions occur:
* If there is a .050 (sometimes expressed as 50 "points") or more difference in the specific gravity reading between the highest
and lowest cell, you have a weak or dead cell(s). Applying an EQUALIZING charge per the battery tester manufacturer’s procedures may
correct this condition. (Please see Section 9.)
* If the battery tester will not recharge to a 75% or more State-of-Charge level or if the built-in hydrometer still does not indicate
"good" (green or blue), which indicates a 65% SoC or better).
* If a moderate load is applied and if there is no or very little current flowing there is an probably an open cell or a
completely sulfated battery tester. Without a load, a voltmeter reading may or may not indicate an open.
* If the digital voltmeter indicates 10.45 to 10.65 volts, there probably is a shorted cell. A shorted cell is caused by plates
touching, sediment ("mud") build-up or "treeing" between the plates.
4.5. Capacity Load Test
Capacity load testing is to determine how good or bad a car or deep cycle battery tester is. The primarily purpose of a car battery tester is to
start an engine, so the battery tester ability to produce current is the most important capacity test. In addition, some car batteries
are only rated in their amp hour or Reserve Capacity. If this is the case, the capacity testing for deep cycle batteries below
should be used.
4.5.1. Car Batteries (High Current Method)
If the battery tester’s State-of-Charge is at 75% or higher or has a "good" built-in hydrometer indication, then you can load test the
car battery tester by one of the following methods:
* With a battery tester conductance tester, test the battery tester. Most auto parts and battery tester stores have battery tester conductance testers and
some stores will test battery tester capacity for free. (Recommended method).
* With a battery tester load tester, apply a load equal to one half of the CCA rating of the battery tester for 15 seconds.
* With a battery tester load tester, apply a load equal to one half the OEM cold cranking amp specification for 15 seconds.
* Disable the ignition and turn the engine over for 15 seconds with the starter motor.
DURING the load test, the voltage on a good c
jamiearr4 