During the warm summer months, it is critical to remember how temperature affects battery health. Heat accelerates the chemical activity in a battery, while cold temperatures will slow it down. The normal battery operating temperature is 77 degrees Fahrenheit.

Warmer temperatures during the summer result in higher temperatures for many battery strings. These increases can result in shortened life, increased performance, increased internal discharge, and increased water usage. This reduction in life is approximately 50% for every 15-degree Fahrenheit rise. This is based on average annual temperature, not simply if your battery room reaches 92 degrees Fahrenheit one time.

Example: Batteries with a normal service life of five years at 77 degrees Fahrenheit will only last two and a half years at 92 degrees Fahrenheit. During the summer you can drastically age your batteries by not keeping them in a temperature-controlled environment.

Below are tips for minimizing the effects of heat on your battery systems:

  • Check your HVAC system in the battery room or cabinet (if available) and make sure that it is functioning properly. Lead Acid batteries like to be in an environment of 77 degrees Fahrenheit which can be a challenge during the summer. For VLA batteries check the temperature of your electrolyte to determine battery temperature as it can be different from ambient temperature. For VRLA batteries check the temperature of the battery at the negative post.
  • Temperature compensated charging is a great tool you can use to help alleviate some of the heat effects. Some newer chargers come equipped with Temperature Control Sensors on the batteries. This allows for the charge voltage on the batteries to be reduced or increased based on the temperature at the sensor point. Please reach out to us with the charger model and serial number if you aren’t sure if your charger has this functionality.
  • If you do not have temperature-controlled charging as a feature, you can manually adjust charger float and equalize voltage. This is much more challenging to keep up with as you won’t know the temperature daily to adjust the charger to. Most recommended float charge voltages are based on a battery sitting in an environment that is 77 degrees Fahrenheit. Consult your manufacturer’s operation manual for the recommended adjustment based on ambient temperature.

Example: A C&D VLA battery that normally operates at 77 degrees Fahrenheit might have a float voltage of 2.20 volts per cell. The corrected float voltage at 87 degrees Fahrenheit would be 2.172 volts per cell. So, a 60 cell string that normally floats at 132VDC would now be adjusted to 130.30VDC to improve the battery health.

Source: C&D Standby Battery Vented Cell Installation & Operating Instructions (RS-1476)