At what electrolyte temperature should a specific gravity correction be considered when using a hydrometer?

At what electrolyte temperature should a specific gravity correction be considered when using a hydrometer?

• A. Below 59 degrees
• B. Between 59 and 80 degrees
• C. Above 100 degrees
• D. At any temperature

Answer: (A)

Temperature changes the density of electrolyte, and hydrometers are calibrated to read specific gravity at a standard temperature (about 60°F). When the electrolyte is colder than that, it becomes denser, so the hydrometer tends to float higher and indicate a higher SG than the true value. To obtain an accurate SG, you apply a temperature correction, and in many practice guidelines that correction is started when the electrolyte is around 59°F or cooler. At higher temperatures the density effect is smaller and the correction is usually not needed, or is much less, which is why the threshold is set at the cold end. So, correction is considered when the electrolyte temperature is below about 59°F to avoid misreading the battery’s condition due to cold-density effects.

Temperature changes the density of electrolyte, and hydrometers are calibrated to read specific gravity at a standard temperature (about 60°F). When the electrolyte is colder than that, it becomes denser, so the hydrometer tends to float higher and indicate a higher SG than the true value. To obtain an accurate SG, you apply a temperature correction, and in many practice guidelines that correction is started when the electrolyte is around 59°F or cooler. At higher temperatures the density effect is smaller and the correction is usually not needed, or is much less, which is why the threshold is set at the cold end. So, correction is considered when the electrolyte temperature is below about 59°F to avoid misreading the battery’s condition due to cold-density effects.