The beginning of spring can be the end of a cold winter in some parts of the country, but in others, the snow has yet to melt enough to break out your battery-powered golf car from storage. If you’ve done your homework, you know to fully charge your batteries before storing them for any period of time. You should also know that different battery chemistries are affected by freezing temperatures in different ways.
If you’re using Flooded-Lead Acid (FLA) deep-cycle batteries, fully charging them before winter storage prevents the electrolyte from turning to mostly water and freezing. A fully charged FLA battery has a freezing point below -80°F (-62°C) while a discharged battery has a freezing point of 20°F (-6.7°C) or higher. Even though the electrolyte in AGM deep-cycle batteries is ‘absorbed’ in the separators and electrodes, it is still liquid and susceptible to freezing. Both FLA and AGM lead batteries should be maintained at a high state of charge during storage particularly during winter storage.
Lithium batteries have reduced charge acceptance at low temperatures and should not be charged below 32°F (0°C). The discharge performance of lithium batteries is also reduced significantly at low temperatures and they may not operate at all at very low temperatures due to the protection provided by the built-in Battery Management System (BMS).
Cold temperatures slow down a battery’s chemical reactions and increase a battery’s internal resistance causing a reduction in capacity particularly at higher discharge rates. Therefore, for every 18°F (10°C) below room temperature, the battery loses about 10% of its capacity. If you’re using your golf car in very cold temperatures, be aware that your driving range and hill climbing capability will be significantly reduced. It will also take longer than usual to fully charge your batteries so be sure to check the charger and batteries for full charge before using the golf car. Some chargers have built-in temperature compensation to allow for charging at low and high temperatures but others do not. Check your charger’s owner’s manual for operation at extreme temperatures.
Continued use of batteries at less than full charge will result in progressive discharge and potential sulfation. Checking your batteries’ state of charge regularly and using equalization charging as necessary can prevent this condition. For FLA batteries, take hydrometer readings of each cell and use the temperature correction factor for specific gravity. As a rule of thumb, subtract four points (.004) from your hydrometer reading for every 10°F below 80°F (5.6°C below 27°C). Why? Because the optimum temperature to take a hydrometer reading is 80°F (27°C). A fully charged FLA battery should read approximately 1.270 SG.
For AGM batteries, it is best to use a voltmeter to determine if it is fully charged. Check with the battery manufacturer’s specifications to determine the voltage at full charge. Lithium batteries, with their BMS, can determine if it’s okay to charge the battery depending on battery temperature. Charging or discharging actions will be temporarily disabled if the battery is below or above set temperatures. Check the manufacturer’s specifications to determine if the battery is too cold to be charged.
In general, be aware that the battery chemistry you are using in your golf car can determine how well it will perform, if at all, in extremely cold temperatures. Always check the battery manufacturer’s website for recommendations and charging methods for the type of battery you are using. To find additional resources on battery maintenance and ways to increase battery efficiency and service life, visit U.S. Battery’s website at www.usbattery.com.
