How long can batteries be stored?

Batteries should be stored indoors, preferably at 77°F (25°C) or in a cool (60°F to 85°F), dry location and placed in service before the date stamped on the shipping carton. The indicated storage time is based on storage at 77°F (25°C); approximately 6 months for Lead Calcium alloy and approximately 3 months for Lead Antimony cells. See your product manual for specific details.

Exercise caution when operating or storing batteries at low temperatures because of the possibility of electrolyte freezing. Although the specific gravity of a fully charged battery may present no freezing problem, the discharged specific gravity may. See your product manual for more information.

Can lubricants be used for cell installation onto open racks?

What is a UPS (Uninterruptible Power Supply)?

When should a UPS be used?

An Uninterruptible Power Supply should be used anytime continuous, no-break electrical power is required. Commonly backed-up equipment includes computers of all sizes, industrial controls for manufacturing, telephone equipment, emergency lighting, fire alarms and security systems.

When should the UPS batteries be changed?

Most maintenance-free batteries have a maximum reliable life of 4 years, after which failures are unpredictable. Wet or flooded cell batteries including Ni-Cad can have a 20-year useful life if maintained properly.

How many batteries can fail before the UPS will not work?

It depends on how many strings you have. A string is two or more batteries connected in series (like beads on a necklace). It takes at least one string of batteries to operate a UPS. Think of a string of batteries as a length of chain, with each link being one battery. One battery failure is like breaking a link in the chain, so if you have one string and one battery fails, you have no UPS.

Why is proper installation so important for a successful UPS system?

If a UPS is not properly selected and installed correctly, you can have more problems using a UPS then not having one at all. A correct UPS installation will not happen by accident; someone knowledgeable and experienced should be consulted when planning a UPS purchase or when trying to correct an existing installation.

If I have a generator do I still need a UPS?

Yes. A generator takes a few seconds to start up and connect to the powered equipment. A computer would shut down in those few seconds, so a UPS acts as a bridge to keep equipment operating during the dead time.

How long does it take for the UPS batteries to recharge?

On average it takes 12 to 16 times the discharge time for the UPS batteries to recover. (A 15-minute use of battery will require three to four hours recharge time.) After each power outage, the recharge process begins immediately. It is important to note that the load is fully protected while the batteries are recharging. However, if the batteries are needed during recharge time, runtime will be less than it would be if the batteries were fully charged.

What causes a UPS to be overloaded?

There are two possible answers: (1) the UPS was undersized (the load is rated at 1200 VA but a 1000 VA UPS was provided) or (2) the customer plugs more equipment into the UPS than it was designed to handle.

If VA information is not available for a device, how do I determine the rating?

Voltage and current information can be found on the back of each device, usually near the product model and serial numbers.
Volts x Amps = VA per device
If only Watts are given:
Watts x 1.4 = VA
VA/1000 = KVA

How do I know how much to add for growth?

A good rule of thumb is that the computer load should be about 60% of the UPS KVA/KW capacity.

What are some of the different types of UPS Systems?

Off Line
In this type of supply, power is usually derived directly from the power line, until power fails. After power failure, a battery-powered inverter turns on to continue supplying power. Batteries are charged, as necessary, when line power is available. This type of system is sometimes referred to as "standby" UPS.

The quality and effectiveness of these devices varies considerably; however, they are generally less expensive than "true on-line" systems. The time required for the inverter to come online, typically called the switchover time, varies by unit.

Line Interactive
These units are the same as Off Line units, where the inverter only powers the load during battery run, with the addition of limited voltage regulation. The voltage boost (increase) or buck (decrease) is in set increments (usually they can change the input voltage by exactly 10%). This is done by tap switching on an auto transformer that does not provide isolation. The amount of voltage regulation on Line Interactive units varies from model to model. Some only have one voltage boost stage, others two, and some include a voltage decrease stage. Units in this category include ferro-resonant, which give some voltage regulation with the addition of an Off-Line UPS.

Online Double Conversion
Online UPS systems power the critical load from the inverter of the UPS at all times, which means there is no switchover time. This protects the load from variations of the utility power (brownouts, blackouts, surges, sags, etc.) at all times. Low voltage on the input is boosted on the output without discharging the battery.

Most True Online Systems have power factor correction and produce a clean sine wave output. Battery conservation and management are optimized. The inverter powers the load continuously. True Online Systems always regenerate the input power, so the output is always 120VAC, 60 Hz (or whatever voltage it is set for), regardless of input voltage level.

What is power factor?

Power factor is like the ratio in a mug of beer of the foam (which is not very drinkable, just like VA is not real power) to the actual liquid in a mug. The ratio of the liquid/foam is similar to watts/VA. Just like you would not like to pay for a mug that is all foam, you don't want to pay for VA instead of watts from the utility company. The output of UPS systems is rated in VA because computer loads need a higher VA than watts (usually with a .8 or .7 power factor – the ratio the of watts to VA).

Power factor correction converts VA to watts (in our beer analogy, foam to drinkable liquid). This reduces the peak currents on the input (which can heat up and overload wiring, especially in older buildings) and actually reduces power bills (utility companies charge for VA, not watts).

In summary, computer power supplies distort the input AC. Poor power factor can cause certain wiring in older buildings to overheat, increase your electricity bills and more.