Which UPS system is the right one? Considerations for the selection of UPS systems

A UPS system is advisable to protect you from a power failure or electrical voltage fluctuations and interruptions. This stabilizes the electrical voltage in your IT network by intervening when problems are detected in the power grid. This blog post gives you an overview of UPS systems to help you choose the right one for your company.

What is an uninterruptible power supply?

A UPS protects your technical devices from faults in the power grid by supplying them with battery power. The UPS is used automatically, especially during short interruptions, more often than you might think. The UPS is therefore very important to provide additional protection for your IT systems.

A UPS consists of one or more battery modules. If the UPS only has one, it is activated continuously. If there are several battery modules, some of the modules are only activated as soon as more load is required. This means that one module is activated and the other is on standby, but always ready for use.

Use of UPS systems:

A UPS system is integrated in combination with emergency power systems.
UPS devices are mainly used in hospitals, data centers, but also in small offices and other facilities where a permanent power supply is a top priority. Whether you are a small or large company, a UPS helps with your IT security.

Depending on the type of UPS, it protects against the following faults:

• Power failure
• Overvoltage
• Undervoltage
• Harmonics
• Frequency deviations

Advantages of using a UPS

• Continuity of work: They continue to provide power to your devices, even during power outages, minimizing work interruptions and maintaining the flow of work. They also ensure continuous availability of networks and applications by preventing downtime.
• Data integrity and protection: They protect against data loss and corruption. This is particularly important in environments where important data is handled.
• Prevention of hardware damage in security, communications or entertainment: They stabilize the power supply, protecting hardware components from damage. This extends the service life of your devices and minimizes downtime.
• Protection against overvoltages

The 3 classes of UPS systems:

UPS systems have different requirements and are therefore divided into 3 different classes:

Making the right choice

When choosing a UPS, there are many aspects to consider and you should define which systems in your company the UPS will be used for.

The output power of the selected UPS should be 20 - 25 % higher than the total power consumption of the connected systems. However, the more systems that are connected to the UPS, the shorter the bridging time, i.e. the period during which the UPS can continue to supply the systems evenly in the event of a power failure. Therefore, only the most important systems should be connected to the UPS.

Our recommendation:
If you want protection for private use, home office or entertainment, an offline UPS is sufficient, as these are quite inexpensive. For small companies with several networks or computers with high performance, as well as many storage devices, a line-interactive UPS is the right choice. These are very efficient and reliable and offer greater protection than offline UPSs. If there is power up to 20KW, i.e. for large server rooms and network cabinets, you should opt for an online UPS. This also applies to sensitive devices that require a continuous power supply.

This is just a recommendation when choosing a UPS. If you are unsure which UPS is the right one for your application, you can contact us. We will be happy to advise you in detail and help you make the right choice.

Batteries and battery life

The UPS battery takes over the power supply in the event of a power failure and is the most important part of a UPS system. Great importance should therefore be attached to monitoring and maintaining the battery.

Batteries with open cells, for example, should be serviced regularly and replaced when they become weaker. The service life of UPS batteries is determined by the optimum conditions in which the battery is exposed. The better the conditions, the longer the battery will last.

A UPS emits heat regardless of the battery type. If the UPS is not air-conditioned, the battery life is shorter than if the UPS system is air-conditioned. The optimum operating temperature is 20 to 25 °C. In addition, the UPS batteries should not be stored for longer than 6 to 12 months or repeated discharging and recharging of the battery should be avoided. In the event of fluctuations in your power grid, the system switches over to the internal battery without delay, switching from direct current to alternating current (see illustration).

Types of batteries commonly used today

The most common type of battery used in UPSs is the valve regulated lead acid battery (VRLA). These VRLA batteries are usually sealed in a polypropylene housing, which prevents liquid from leaking, spilling or dripping. As these batteries do not contain refillable water, it is important that the evaporated water is recycled to ensure their service life and functionality. If the evaporation is too strong, e.g. due to excessive heat during the charging process, or if water is lost, the service life of the battery will be shortened. A distinction is made between hydrogen cyanide batteries with closed or open cells:

Hydrogen cyanide batteries with closed cells:

• Compact design; can contain gel or liquid electrolytes
• Are contained in sealed packaging with small vents
• Sealed: no need for regular topping up of water and lower risk of electrolyte loss compared to open cells
• Can be placed in any room without special construction or protective measures
• Warranty: 10 years
• Service life: 3-5 years

Hydrogen cyanide batteries with open cells:

• Wide availability, making it easier to expand and replace battery capacity
• More cost-effective than hydrogen cyanide batteries with closed cells or lithium-ion batteries
• Longest service life: 25 years
• Must be located in separate, fire-resistant rooms with acid drains, hydrogen detection alarms, exhaust fans and eyewash stations
• Regular maintenance required, but easy to maintain by topping up the water
• Easy to adjust and repair

Lithium-ion batteries are another type of battery:

Lithium-ion batteries:

• No special rooms or constructions required; more efficient in a wider temperature range, less susceptible to temperature changes
• Lighter weight and more compact size than hydrogen cyanide batteries, simplifies installation and saves space
• Faster charging times, minimized downtime, higher UPS availability
• Higher energy efficiency and lower self-discharge
• No regular maintenance required; but recommended to prevent potential problems
• Longer service life: several thousand charging cycles; more than lead-acid batteries (several hundred cycles)
• More environmentally friendly than hydrogen cyanide batteries, as they do not contain metals such as lead

Factors that influence battery life

Batteries in UPSs have a limited service life that is difficult to determine precisely.

Four main factors influence this service life:

• Ambient temperature: fluctuations affect performance
• Battery chemistry: limited service life of UPS batteries (regardless of whether guidelines are adhered to)
• Charging cycles: use and charging of the battery reduces its capacity, so it should be replaced
• Maintenance: Regular maintenance to extend service life and detect potential problems at an early stage

Set up a UPS system and benefit from security

We hope that this article has given you the information you need about UPS systems. In our store you have the choice between many different UPS systems that could suit your company. Still unsure about the UPS class? We will be happy to assist you and let a specialist advise you on your choice.

Not sure whether it's worth buying a UPS system? In our blog post on "Power failure and overvoltage" you can find out more about how you can protect yourself with a UPS or other options.

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