How To Take Cold Temperature Hydrometer Readings For Optimum Battery Performance

Don’t be alarmed if your golf car fleet operates differently as the winter season sets in. Charge and discharge performance of lead-acid batteries is temperature sensitive, so colder weather can result in lower runtimes. Colder weather can also prevent batteries from getting a full charge, so it’s important to take periodic specific gravity readings. When taking specific gravity measurements, be sure to compensate for the temperature of the battery electrolyte in order to get an accurate reading.

Lead-Acid Battery Temperature Correction Factor

Specific gravity readings are referenced against a standard temperature of the electrolyte (not the ambient temperature) of 80-degrees F or 27-degrees C. As a rule of thumb, subtract four points (.004) from your hydrometer reading for every 10-degrees below 80 °F. In Celsius, subtract four points (.004) for every 5.6-degrees below 27°C.

As an example; if the temperature of the electrolyte is 50 °F and your battery specific gravity reading is 1.200, you must subtract .012 from your reading. In this case .004 for every 10-degrees equals .012. Subtract this from 1.200 and your corrected specific gravity reading is 1.188. In this reading, the battery cell is less than 50 percent charged and should be recharged before being put into service. If your corrected specific gravity readings are low, simply charge the batteries until the readings are above 1.265 or above your battery manufacturer’s specification.

Temperature also affects discharge rates. A cold battery will self-discharge slower than a warm battery, but will also exhibit lower capacity. Lower temperature increases the resistance in the battery and causes a reduction in battery capacity. A general rule of thumb to find out the overall capacity of your fleet’s batteries is to figure that for every 15-20 degrees below 80 F, the battery loses 10 percent of its capacity.


Batter_SOC-Temp- Infographic



If your golf car fleet goes into storage during the winter months, make sure that all of the batteries in the fleet are fully charged. This will prevent the electrolyte from freezing and prevent premature battery failure. While in storage, batteries should be boosted every 60 days in colder months and every 30 days in warmer months.

For more information on golf car batteries, run-time ratings, and maintenance tips to keep golf car batteries running longer, visit