BATTERY FAQ

1. What is the “end of useful life”?

The IEEE defines “end of useful life” for a UPS battery as being the point when it can no longer supply 80 percent of its rated capacity in ampere-hours. When your battery reaches 80 percent of its rated capacity, the aging process accelerates and the battery should be replaced.

2. How can I ensure that my UPS batteries are maintained and serviced properly?

With proper maintenance, battery life can be predicted and replacements scheduled without interrupting your operations.

These are IEEE and OEM recommendations for general maintenance:

• Comprehensive maintenance programs with regular inspections
• Re-torque all connections, as required
• Load testing
• Cleaning the battery area, as required

3. Do I have to replace my UPS batteries with the same brand of batteries?

Eaton recommends that if you use brand X and need to replace one or two batteries in the string, you should use the same brand because it will have the same characteristics. If you need to replace the whole string, then you can change brands with fewer risks.

4. Are maintenance-free batteries maintenance free?

Though sealed batteries are sometimes referred to as maintenance-free, they still require scheduled maintenance and service. The term maintenance-free refers to the fact that they don’t require fluid. Preventive maintenance is the key to maximizing your UPS battery service life.

5. What about battery disposal?

It’s imperative that your service technicians adhere to EPA guidelines for the disposal of all UPS batteries. Remember, it’s the owner’s responsibility to make sure these guidelines are followed.

6. Is there any difference between the batteries used by smaller UPSs, from 250 VA to 3 kVA, and the ones used by larger UPSs?

While basic battery technology, and the risks to battery life, remains the same regardless of UPS size, there are some inherent differences between small and large applications. Smaller UPSs typically have only one VRLA battery that supports the load and needs maintenance. As systems get larger, increasing battery capacity to support the load gets more complicated. Larger systems may require multiple strings of batteries, introducing complexity to battery maintenance and support. Individual batteries must be monitored to prevent a single bad battery from taking down an entire string and putting the load at risk. Also, as systems get larger, wet-cell batteries become much more common. The differences in battery maintenance between VRLA and wet-cell batteries discussed earlier apply.

7. Our facility was damaged by a flood and our batteries were partially submerged in water. What should we do?

The first concern in this situation is safety. Containing any contamination is critical to preventing hazards to workers and the environment.

8. My UPS has been in storage for over a year. Are the batteries still good?

As batteries sit unused, with no charging regimen, their battery life will decrease. Due to the self-discharge characteristics of lead-acid batteries, it’s imperative that they’re charged periodically during storage or permanent loss of capacity will occur. To prolong shelf life without charging, store batteries at 10°C (50°F) or less.

9. What is thermal runaway?

Thermal runaway occurs when the heat generated in a lead acid cell exceeds its ability to dissipate it, which can lead to an explosion, especially in sealed cells. The heat generated in the cell may occur without any warning signs and may be caused by overcharging, excessive charging, internal physical damage, internal short circuit or a hot environment.

10. Is it safe to transport sealed batteries?

VRLA batteries marked as “non-spillable” are safe and approved for all transportation methods.

11. What is the difference between hot-swappable and user-replaceable batteries?

Hot-swappable batteries can be changed out while the UPS is running. User-replaceable batteries are usually found in smaller UPSs and require no special tools or training to replace. Batteries can be both hot-swappable and user-replaceable. Please check your user’s guide for details on your UPS batteries.

12. How is battery runtime affected if I reduce the load on the UPS?

The battery runtime will increase if the load is reduced. As a general rule, if you reduce the load by half, you triple the runtime.

13. If I add more batteries to a UPS can I add more load?

Adding more batteries to a UPS can increase the battery runtime to support the load, but it doesn’t increase the UPS capacity. Be sure your UPS is adequately sized for your load, then add batteries to fit your runtime needs.

14. What is the average lifespan of UPS batteries?

The standard lifespan for VRLA batteries is three to five years; for wet-cell batteries it’s up to 20 years. However, expected life can vary greatly due to environmental conditions, number and depth of discharge cycles, and adequate maintenance.

Having a regular schedule of battery maintenance and monitoring will ensure you know when your batteries are reaching their end-of-life.

15. Why are batteries disconnected on small, single-phase UPSs when they’re shipped?

This is so that they’re in compliance with Department of Transportation regulations.

16. If I have the serial number from the Eaton UPS or battery cabinet, can I find out how old the batteries are?

Every Eaton battery has a manufacturer date code that indicates when it was made. The battery or battery cabinet will also feature a sticker for each time the batteries have been recharged while in storage. Stored batteries require charging periodically during storage to avoid loss of capacity. Recharging stored batteries doesn’t affect battery warranty.

17. Will Eaton replace batteries for other manufacturers’ UPSs?

Yes. Eaton batteries works on nearly all other manufacturers’ UPSs. In addition, we have extensive knowledge of Best Power, Deltec, IPM and Exide Electronics models because these product lines were purchased by Eaton.

18. What are the risks associated with a lack of battery maintenance?

The primary risks of improperly maintained batteries are: load loss, fire, property damage and personal injury.

19. Who are the major battery manufacturers?

There are many battery manufacturers, but the major ones are: C&D, Enersys, CSB, Yuasa, Panasonic and GS – to name a few.

20. If I have one bad battery, should I only replace that faulty battery, or replace the entire battery string?

Having one faulty battery doesn’t mean you have to replace the entire battery string, which can be very costly. You can replace the bad battery with a fully charged unit but you also need to test the health of the entire string to the cell level to identify if additional strain from the faulty battery damaged other units.

All it takes is one bad battery to ruin an entire string and bring your systems down during a power outage or other interruption.

There is no precise way to predict battery failure. Continuous battery monitoring and scheduled maintenance are the most effective way to identify bad batteries early enough for spot replacement.

21. Why do batteries fail?

Batteries can fail for a multitude of reasons, but common reasons are:

• High or uneven temperatures

• Inaccurate float charge voltage

• Loose inter-cell links or connections

• Loss of electrolyte due to drying out or damaged case

• Lack of maintenance, aging

22. What is the importance of power density when talking about batteries?

Batteries differ markedly in the number of watts per cell. A higher density battery provides more runtime for the footprint. You may even find you can reach your runtime requirements with fewer battery cabinets, which reduces upfront and lifetime costs of battery preventive maintenance.

23. How is battery performance generally measured?

Batteries are generally rated for 100+ discharges and recharges, but many show a marked decline in charging capacity after as few as 10 discharges. The lower the charge the battery can accept the less runtime it can deliver. Look for batteries with a high-rate design that sustains stable performance for a long service term.

24. When are 10-year design life SVRLA batteries typically replaced in standard UPS applications?

UPS battery life depends on a number of factors, including operating temperature, number and duration of discharges, and if regular preventive maintenance is performed. While it’s theoretically possible for SVRLA batteries to last 10 years under optimum conditions, the industry typically recommends full replacement between years four and five for reliability purposes in UPS applications.

25. How can I determine the age of a VRLA battery?

Batteries shipped prior to December 31, 1999 have a three-digit shipping code with the first digit as the year and the following two as the month in which the battery was shipped from the factory. For example, a code of 910 would be interpreted as 1999, October. Batteries shipped on or after January 1, 2000 have a four-digit shipping code with the first two digits as the year and the following two as the month in which the battery was shipped from the factory. For example, a code of 0010 would be interpreted as 2000, October.