If the electrolyte temperature is outside the 70º F to 90º F range, should a temperature correction be applied when measuring the specific gravity?

• A. Yes
• B. No
• C. Only if the battery is new
• D. Only if the electrolyte is spilled

Answer: (A)

Because the density of electrolyte changes with temperature, the specific gravity reading is only directly comparable to the standard chart at a set temperature. When the electrolyte temperature is outside the 70°F to 90°F range, you must apply a temperature correction so the SG value reflects what it would be at the standard temperature used for the chart. If the electrolyte is hotter than the standard, the reading will be lower than the true SG and should be adjusted upward; if cooler, the reading will be higher than the true SG and should be adjusted downward. This correction keeps the SG measurement accurate for assessing the battery’s state of charge.