How To Use A Battery Hydrometer

How to Employ a Battery Hydrometer (Never Insert a Metal Thermometer into a Bombardment!)

A battery hydrometer is used to test the state of charge of a battery cell. This is performed by measuring the density of the electrolyte, which is accomplished by measuring the specific gravity of the electrolyte. The greater the concentration of sulfuric acid, the more dense the electrolyte becomes. The higher the density, the college the state of charge.
Specific gravity is the measurement of a liquid that is compared to a baseline. The baseline is water which is assigned a base of operations number of ane.000. The concentration of sulfuric acid to water in a new golf machine battery is ane.280 which ways that the electrolyte weighs 1.280 times the weight of the same volume of h2o. A fully charged battery will test at ane.275 – i.280 while a discharged battery will read in the 1.140 range.
! NOTE !

Do non perform a battery hydrometer exam on a battery that has but been watered. The battery must go through at to the lowest degree one charge and belch cycle in gild to allow the water to fairly mix with the electrolyte.
The temperature of the the hydrometer reading must exist corrected to lxxx° F (27°C). It is important to recognize that the electrolyte temperature is significantly different from the ambient temperature if the vehicle has been operated.
Hydrometer Testing Process: Warning! Batteries Contain Sulfuric Acid
E'er Use Personal Protective Equipment from Contact with Sulfuric Acid

Eye Protection. Safety Gloves. Rubber Frock. Closed Toe Shoes.
Avoid Wearing Whatsoever Cotton Cloth as Battery Acid volition Deliquesce Fabric

1. Describe electrolyte into the hydrometer several times to permit the thermometer to suit to the electrolyte temperature and note the reading. Examine the color of the electrolyte. A brown or gray coloration indicates a problem with the battery and is a sign that the bombardment is nearing the end of its life.

2. Draw a total sample of electrolyte into the hydrometer to permit the bladder to float freely.

3. Agree the hydrometer in a vertical position at eye level and note the reading where the electrolyte meets the calibration on the float.

4. Add or subtract 4 points (.004) to the reading for every 10° F (half-dozen° C) the electrolyte temperature is above or beneath 80° F (27° C). Suit the reading to conform with the electrolyte temperature, e.g., if the reading indicates a specific gravity of 1.250 and the electrolyte temperature is ninety° F (32° C), the ane.250 which gives a corrected reading of 1.254. Similarly if the temperature was 70° F (21° C), subtract reading of 1.246.iv points (.004) from the i.250 to give a corrected

v. Examination each prison cell and note the readings (corrected to 80° F or 27° C). A variation of fifty points between any two jail cell readings (instance one.250 – 1.200) indicates a problem with the low reading jail cell(s).
12.60 to 12.74 = 85 to 100% Charged
12.40 to 12.59 = 75 to 85% Charged
12.xx to 12.39 = l to 75% Charged
12.00 to 12.xix = 25 to 50% Charged
12.00 & Below = Fully Discharged

As a battery ages the specific gravity of the electrolyte will decrease at total charge. This is not a reason to replace the bombardment providing all cells are inside fifty points of each other.

Since the hydrometer exam is in response to a vehicle exhibiting a performance problem, the vehicle should exist recharged and the exam repeated. If the results indicate a weak cell, the battery or batteries should exist removed and replaced with a good battery of the same brand, type and judge age.