UPS Battery Storage Requirements

How you store your UPS batteries directly affects their safety, reliability, and longevity. Here’s what you need to know to maintain optimal performance.

At the core of our work is a commitment to safety, unparalleled reliability, and quality – values that guide how we protect our people, your people, and the critical infrastructure we support.  

 

Safe and reliable performance of your UPS batteries starts with proper storage.  

 

Whether lead acid, lithium-ion, or another chemistry, all UPS batteries are highly sensitive to temperature, humidity, and environmental changes. Even brief power interruptions can impact storage conditions and compromise performance.  

 

This page outlines best practices and technical requirements for storing and operating UPS batteries currently in Mitsubishi Electric’s installation base. 

 

 

Important Notes 

  • Please review and follow all battery manufacturer manuals, information, and instructions for detailed storage and handling requirements.  
  • Please make sure to follow all safety and handling instructions and guidelines outlined by all battery manufacturers, impacted municipalities, and Authorities Having Jurisdiction (AHJ).  

Man in hard hat and safety vest in electrical room.

Lead Acid UPS Battery Storage & Operation Requirements

Storage Requirements

  VRLA (Non-Pure Lead) Pure Lead VRLA
Environment Dry, clean, and preferably cool location
Temperature & Duration

EnerSys HX

  • 6 months at ambient temperature no warmer than 77°F (25°C)
  • 4 months at 86°F (30°C)
  • 2 months at 104°F (40°C)
  • Maximum Storage Time: 2 years from date of shipment date code.

Deka HR

  • 6 months at ambient temperature no warmer than 77°F (25°C)
  • 3 months at ambient temperature of 78°F (26°C) to 90°F (32°C)

EnerSys XE

  • 24 months at 68°F (20°C)
  • 17 months at 77°F(25°C)
  • 12 months at 86°F(30°C)
  • 6 months at 104°F(40°C)

C&D PLP/PLM

  • 24 months at 77°F (25°C) or less
  • For every 15°F (8°C) increase in temperature above 77°F (25°C), storage times will be reduced by half.
Refreshing Charge
  • At 77°F (25°C) a refresh charge must be given to all cells every six months prior to installation in accordance with applicable manufacturers manuals.
  • At 78°F (26°C) to 90°F (32°C) a refresh charge must be applied every 3 months.
  • Charging is advised if the voltage drops below 2.07Vpc.

EnerSys XE

  • Refresh charge applied when cell voltages approach 2.10V per cell or when max storage time is reached.
  • Check required every 6 months, and every 3 months for storage temps above 86°F(30°C).

C&D PLP/PLM

  • Check every 6 months up to 24 months, and every 3 months for storage temps at or above 92F(8°C)
  • If voltage declines to 12.4 VDC or declines to 12.4 VDC before the next voltage check, the batteries should be given a refresh charge.

Operation Requirements

  VRLA (Non-Pure Lead) Pure Lead VRLA
Temperature EnerSys HX

  • Nominal operating temperature: 68°F (20°C) to 77°F (25°C)

Deka HR

  • Nominal operating temperature: 68°F (20°C) to 77°F (25°C)
  • For every 13°F (7°C) increase above 77°F (25°C), battery life is reduced by 50%.
  • Batteries must not be continuously operated below 50°F (10°C).
 EnerSys XE

  • Max operating temperature range: -40°F (-40°C) to 122°F (50°C)
  • Nominal operating temperature: 68°F (20°C) to 77°F (25°C)

C&D PLP/PLM

  • Max discharge temperature: -40°F (-40°C) to 140°F (60°C)
  • Charge temperature: -10°F (-23°C) to 140°F (60°C)
  • Nominal operating temperature: 74°F (23°C) to 80°F (27°C)
General
Any operation outside the nominal parameters of the battery can damage the battery and reduce expected design life.
Float Charging Voltage

EnerSys

2.25Vpc – 2.28Vpc, 2.27Vpc nominal at 77°F (25°C)

 
Deka

2.25Vpc ± 0.01Vpc at 77°F (25°C)

 
C&D

2.25Vpc – 2.28Vpc, 2.27Vpc nominal at 77°F (25°C)
Installation
  • Install batteries in a clean, dry area.
  • The batteries can be installed near the main equipment.
  • Batteries must be installed in accordance with federal, state, and local regulations and the manufacturer’s instructions.
  • Batteries release minimal amounts of gas during normal operation (gas recombination efficiency ≥ 97%).

 

 

Lithium-ion UPS Batteries Storage & Operation Requirements

Storage Requirements

  Samsung Lithium-ion SAFT Flexion Gen 2 Lithium-ion*
Environment
  • Dry, clean, preferably cool location and non-temporary
  • Altitude ≤ 2000m
  • Dry, clean, preferably cool location and non-temporary
  • No direct sunlight, rain, or flooding (IP20)
Temperature, Humidity, & Duration

Storage Durations & Temps

  • 1 month: 4°F (-20°C) – 104°F (40°C)
  • 3 months: 4°F (-20°C) – 104°F (40°C); Mean Daily Max of 30°C
  • 6 months: 41°F (5°C) – 82°F (28°C)
  • Max duration of storage is 24 months with voltage checks and refresh charging
  • Temperature uniformity should be within 5 degrees during the storage period

Humidity

  • Less than 80% humidity non-condensing (Storage Only)

Important Information

  • Recommended storage temp. range: 32°F (0°C) – 77°F (25°C). 74°F (23°C) is optimum
  • Modules shipped at SOC:
    • Road/Sea: 50% SOC
    • Air Freight: 30% SOC

Storage Durations & SOC/Temps

  • 6 months: SOC is 30% and temp is 23°C
  • 10 months: SOC is 50% and temp is 23°C

Humidity

  • 5% to 95% humidity non-condensing
Refreshing Charge
  • Voltage checks are required in 6-month intervals.
  • If Voltage is below 28.712V (3.589V/cell) a refresh charge is required.
  • Refresh charge to 29.104V (3.638/cell)
  • Voltage checks, refresh charging and cell balancing is required every 3 months at 73.4°F (23°C) or less.
  • Recommend recharge to 100% SOC every 3 months and full cell balancing to reduce startup & commissioning timeline.
  • Above 4°F (23°C) refresh charging is required more frequently. Battery module should be kept above 2.5V.

 

*The SAFT lithium-ion battery has been discontinued. The above information is for legacy Flexion Gen 2 only.

 

 

Operation Requirements

  Samsung Lithium-ion SAFT Flexion Gen 2 Lithium-ion*
Operation Definition Operating status is defined as a partially or fully internally bussed individual battery cabinet. This status is regardless of connection to UPS or other external battery cabinets.
Temperature & Humidity

Temperature

  • Recommended Temp: 73.4°F (23°C) +/- 5 degrees Celsius (64°F to 82°F)

Humidity

  • Less than 60% non-condensing

Temperature

  • Recommended Temp: 32°F (0°C) – 95°F (35°C)

Humidity

  • 5% to 95% (non-condensing)
Altitude Max 2,000m > sea level
  • Max 2,000m > sea level (600VDC)
  • Max 3,000m > sea level (516VDC)

 

*The SAFT lithium-ion battery has been discontinued. The above information is for legacy Flexion Gen 2 only.

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