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MEASURING SPECIFIC GRAVITY WITH THE OPTICAL BATTERY/ANTIFREEZE TESTER
This tester is quick, accurate, and reliable. There is no guesswork or arithmetic involved. The tester automatically adjusts for temperature.
The plastic cover and the measuring window must be clean and dry. Wipe clean with a soft cloth. Clean the eyepiece lens. Use clean water to clean dirty areas.
Swing the plastic cover down until it rests against the measuring window.
Make a separate test for each battery cell.
Using the black dipstick, place a few drops of electrolyte onto the exposed portion of the measuring window.
WARNING
Be careful not to splash electrolyte onto you or the equipment.
Point the tester toward a bright light source. When you look through the eyepiece lens, you will see a rectangle with two calibrated scales - battery charge readings on the left scale, antifreeze readings on the right.
The electrolyte sample will divide the rectangle with an area of light and an area of shadow. You read the scale where they meet.
A full charge is 1.225 specific gravity for tropical electrolyte and 1.280 specific gravity for temperate electrolyte.
If below 1.180 specific gravity for tropical electrolyte and 1.225 specific gravity for temperate electrolyte, replace the battery with a fully charged one if you cannot charge it in the field.
COLD WEATHER
Battery capacity is greatly reduced by low temperatures because the electrolyte thickens and is less active. In addition, the engine is harder to crank so the starter motor requires more current. To perform satisfactorily in cold weather, the battery must be kept in peak condition. So when the temperature drops, you will have to keep a closer watch on the battery.
In cold weather do not let the specific gravity drop below 1.250 if you expect the vehicles to start. When the temperature is colder than -20°F, the vehicles should be stored inside where it is warm, if possible. If they must be parked outside, the batteries should be heated during long periods of standby; otherwise, they will not take a charge or have enough capacity for normal use.
The electrolyte is also subject to freezing; the exact freezing point depends on the specific gravity. In a fully charged battery, the electrolyte will freeze at -90°F. As the specific gravity drops, the freezing point rises. The following table shows the freezing point for various specific gravities.
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Specific gravity Freezing point, degrees Fahrenheit
________________________________________
1.000
1.100
1.150
1.200
1.250
1.280 +32
+19
+. 5
-16
-62
-90
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If the battery electrolyte does freeze, the ice forces active material from the plates and can crack plates and containers or buckle plates and break separators. If you try to charge a frozen battery, the grids expand and shed active material. Let a frozen battery thaw out in a room at normal temperature before charging. The battery may be saved if freezing has not already caused too much damage.
If water is added to a battery, it may freeze if it is not immediately mixed with the electrolyte. For this reason, do not add water in freezing temperatures unless the battery is indoors or the vehicle is operated for at least an hour after the water is added.
TROPICAL CLIMATES
The high temperatures found in the tropics create special maintenance problems that you will have to adjust to if you are assigned in one of those areas.
Rapid evaporation of the water will result due to the heat, so keep a close watch on the electrolyte level. Every effort should be made to keep the battery compartment as cool as possible during and after operation. Do not obstruct ventilation holes, or the heat will damage the batteries.
At high temperatures, the acid in the electrolyte is more active, so using a weaker solution will give good results and cause less damage to the plates and separators.
Electrolyte solution used for tropical climates should have a specific gravity of 1.200 to 1.225. You will have to weaken the solution yourself. Do this by drawing electrolyte from a supply that is already mixed to 1.280 specific gravity and add battery water until the mixture has a specific gravity of 1.200 to 1.225. You will need to add about 1 quart of water to 1 gallon of electrolyte.
If the battery was in use before it was sent to the tropics, change the electrolyte in the following manner. Make sure that the battery is fully charged, so there will be no acid left in the plates. Then, remove the vent plugs and tip the battery upside down to drain all the old electrolyte. Refill the battery with electrolyte that has been weakened to 1.200 to1.225 specific gravity.
WARNING
Be careful to avoid getting any of the electrolyte on yourself or your clothes. The acid can cause painful burns and will eat holes in your clothing.
The following table shows various specific gravities and the state of charge for batteries with weakened electrolyte for use in the tropics.
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Specific gravity of electrolyte used in tropical climates State of battery charge
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1.200 - 1.225
1.180
1.135
1.090
1.045 Fully charged
75 percent
50 percent
25 percent
Discharged
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When the electrolyte in a battery has been weakened, a tag showing the full charge specific gravity should be attached to the battery. These batteries should also be identified by a white dot about 1 inch in diameter painted on the top of the battery where it can be easily seen. |
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1. Electrical System
2. The Battery
3. The Starter
4. The Alternator
5. The Voltage Regulator
6. Lighting
7. Lighting System Basics
8. Interior Lights
9. Voltage
10. Turn Signals and Hazard Lights
11. The Horn
12. Windshield Wipers
13. The Defroster
14. Electrical Symbols
15. Types Of Electrical Circuits
16. Electrical Circuit Defects
17. Introduction To Automotive Batteries
18. Battery Construction
19. Battery Operation
20. Specific Gravity
21. Voltage And Capacity
22. Battery Ratings
23. Testing Automotive Batteries
24. Preventive Maintenance Of Batteries
25. Optical Battery & Antifreeze Tester
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