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What Is Temperature Compensated UPS Battery Charging?

Temperature compensated charging helps to prolong battery life by dynamically adjusting the voltage depending on the ambient temperature.

In colder temperatures, it ensures maximum UPS battery charge. While it reduces the risk of overcharging in warmer operating temperatures. 

Ambient temperatures alter the chemical reactions that occur within batteries. It is generally accepted that battery life halves for every constant 10°C rise in temperature above the recommended 20-25°C.

In fixed charge voltage systems, there is a danger that batteries undercharge when kept in cold conditions. On the other hand, they can overcharge if the ambient temperature is too warm.


How Does Temperature Compensated Battery Charging Work?

Temperature compensated battery charging offers a solution to these issues. Special circuitry fitted into the UPS dynamically adjusts the recharge voltage depending on changes to the ambient temperature. In essence, the higher the temperature, the lower the recharge voltage.

Reducing the charge voltage at higher temperatures optimises the chemical reaction. Without this compensation occurring, the batteries may overcharge. This produces excess hydrogen that can build up pressure inside the cell.

In a worst-case scenario, this pressure may be enough to vent a sealed battery. This unbalances its chemical equilibrium and causes permanent damage.

On the opposite end of the spectrum, batteries require a higher charge voltage in colder conditions. Failure to increase the voltage will undercharge the battery and limit its capacity.

All batteries have a finite service life that will deteriorate over time. But compensating the voltage based on ambient temperature helps keep the chemical balance stable and prolong its life.


What Are The Benefits Of Temperature Compensated Charging?

  • Reduces the risk of venting and permanent damage to cells in warm ambient temperatures
  • Ensures batteries are 100% charged in cooler conditions, which helps to maximise UPS runtime
  • Prolongs battery life by limiting deterioration in float charging applications
  • Limits electrolyte maintenance on flooded battery cells


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Lifespan of UPS batteries

Batteries are essential for UPS correct functioning. In this whitepaper we explain the main important factor that affect their duration and we provide some recommendations for optimizing the UPS + batteries system, in order to maximize its lifespan and general availability.