S&C Electric Company

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PureWave UPS™ Systems

Batteries

Power module

Batteries have a mixed reputation in UPS applications. Batteries provide instantaneous standby power, but many users experience poor reliability even though they've performed extensive battery maintenance. In the PureWave UPS System, the batteries are applied in such a way as to eliminate this problem.

Battery Characteristics

The PureWave UPS System is designed around the operating characteristics of the Group 31 deep-cycle sealed lead-acid battery. This battery is a perfect match for UPS applications, where high power, short duty-cycle operation is required. The high-volume production and proven track record of this battery further contributed to its selection.

On-Line Versus Off-Line Application

In a conventional on-line UPS system, the batteries are continuously connected to the energized dc bus, causing dissipation of electrolyte and prohibiting proper equalization charging, as well as exposing the battery string to AC ripple. Battery maintenance requirements are increased and battery life is significantly shortened.

But in the off-line PureWave UPS System, the batteries are connected to the energized bus only when the system is supplying power to the load. No battery maintenance is needed and battery life is increased.

Equalize Charging

Proper battery equalization requires that the terminal voltage of each battery be raised at least 20% to insure all batteries in the string are at the same state of charge (at 100% rating).

In a conventional on-line UPS system, the batteries cannot be properly equalize-charged because — with the batteries continuously connected — dc bus voltage can’t be raised more than 5%.

In the PureWave UPS System, however, the batteries are automatically equalize-charged every two months.

No Maintenance Required

In addition to the off-line design of the PureWave UPS System, the batteries themselves include features that eliminate the need for routine maintenance, including:

  • Reserve electrolyte capacity.
  • No lead post terminals. A stainless-steel insert in each battery post, along with a Belleville washer, obviates the need to check and tighten connections.
  • The PureWave control system continuously monitors the status of each battery string and tracks battery usage. Battery replacement is predictable and can be scheduled in a timely manner.

Warranty

S&C provides a non-prorated, five-year, 100% warranty on the batteries. Manufacturers of on-line UPS systems, on the other hand, offer a one-year battery warranty having a value prorated over 5 to 10 years.