Author: Vicky Prince

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Lithium-Ion UPS vs VRLA UPS

Lithium UPS

Our Lithium Ion UPS range is an impressive series of UPSs with internal Lithium Ion batteries, that make the units efficient, lightweight and more environment friendly. They also reduce the whole life costs of the UPSs. We have conducted some tests to show you how the Lithium-Ion UPS compares to the VRLA UPS in terms of runtime.

Each unit is connected to 1800W load. The Lithium UPS battery capacity is 48V 9.9Ah = 475VAh. The VRLA UPS battery capacity is 72V 9Ah = 648VAh. Although the Lithium UPS has only 75% of VRLA UPSs battery capacity, the runtime results are outstanding! See the video below:

We provide 5-year warranty on the Lithium-Ion UPS systems including the batteries.
Lithium-Ion UPS only from Power Inspired. Learn more at www.lithium-ups.com and register your interest.

Lithium-Ion UPS

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Transfer times in UPS – what are they and how will they affect my equipment?

Transfer time in UPS

UPS transfer time

“What is transfer time in UPS?”

The definition of transfer time, sometimes also called switchover time, says it is the amount of time a UPS will take to switch from utility to battery supply during a mains failure, or from battery to mains when normal power is restored. What this means is that when the main power supply fails, the UPS will need to switch to a battery mode to provide sufficient power and ensure smooth running of the attached equipment. The transfer time duration differs, depending upon the UPS system attached. It should, however, always be shorter than your equipment’s hold up time. Hold up time is the amount of time your equipment is able to maintain consistent output voltage during a mains power shortage.

Line interactive UPS systems, such as our VIX or VIS series, have transfer time typically between 2-6 milliseconds. For regular computer based systems, where hold up time is approx. 5 milliseconds, line interactive UPS systems are usually sufficient; however some computer systems, as well as other critical sensitive equipment, are more sensitive and require shorter transfer time. Hence in this case you should always choose UPS with zero transfer time like our VFI series.
If your equipment is critical and doesn’t tolerate even slightest power distortion, we recommend choosing online double conversion UPS technology with zero transfer time to ensure your equipment has the highest degree of protection.

 

Here’s a quick look up of transfer times for Power Inspired UPS systems:

 

Product UPS technology Typical transfer time
VIX3065 Line interactive UPS Typically 2-6 milliseconds
VIX1000N Line interactive UPS Typically 2-6 milliseconds
VIX2150 Line interactive UPS Typically 2-6 milliseconds
VIX2000N Line interactive UPS Typically 2-6 milliseconds
VIS1000B Line interactive UPS with sinewave inverter Typically 2-6 milliseconds
VIS2000B Line interactive UPS with sinewave inverter Typically 2-6 milliseconds
VFI1500B Online double conversion UPS Line to battery 0 milliseconds
Line to bypass Approx. 4 milliseconds
VFI3000B Online double conversion UPS Line to battery 0 milliseconds
Line to bypass Approx. 4 milliseconds
VFI3000BL Online double conversion UPS Line to battery* 0 milliseconds
Line to bypass Approx. 4 milliseconds
VFI6000BL Online double conversion UPS Line to battery* 0 milliseconds
Line to bypass Approx. 4 milliseconds
VFI10KBL Online double conversion UPS Line to battery* 0 milliseconds
Line to bypass Approx. 4 milliseconds
VFI1000T Online double conversion UPS Line to battery 0 milliseconds
Line to bypass Approx. 4 milliseconds
VFI3000T Online double conversion UPS Line to battery 0 milliseconds
Line to bypass Approx. 4 milliseconds
VFI10KT Online double conversion UPS Line to battery 0 milliseconds
Line to bypass Approx. 4 milliseconds
TX1K Online double conversion UPS with isolation transformer Line to battery 0 milliseconds
Inverter to bypass 4 milliseconds
Inverter to ECO Less than 10 milliseconds
TX3K Online double conversion UPS with isolation transformer Line to battery 0 milliseconds
Inverter to bypass 4 milliseconds
Inverter to ECO Less than 10 milliseconds
TX6K Online double conversion UPS with isolation transformer Line to battery 0 milliseconds
Inverter to bypass 4 milliseconds
Inverter to ECO Less than 10 milliseconds
TX10K Online double conversion UPS with isolation transformer Line to battery 0 milliseconds
Inverter to bypass 4 milliseconds
Inverter to ECO Less than 10 milliseconds

*unit doesn’t contain internal batteries, requires external battery pack/cabinet

Transfer times are dependent on which stage the power interruption occurs in. That’s why the transfer times stated in the above table are approximate.
As previously mentioned, transfer times also measure the amount of time it takes for the UPS to switch back to mains. The transfer back to mains power is always controlled with minimal interruption as this transfer is planned. As opposed to an unplanned mains failure which happens suddenly and hence a variation in the actual time taken.

transfer time

We have conducted a transfer time measurement using an oscilloscope (photograph above). For purpose of this exercise, we have used a standard line interactive UPS system and stimulated a power cut. The oscilloscope managed to capture the transfer time which on this occasion lasted 15 milliseconds, due to the original sine wave being interrupted at the peak of the cycle.

 “How does transfer time affect my equipment?”

That’s simple – if your equipments tolerance is below UPS transfer time, the UPS will not provide power in sufficient time in order to keep your equipment running.
Let’s say you have highly sensitive laboratory equipment with hold up time of 2 milliseconds. Line interactive UPS will not be sufficient in this case as it will not switch to battery mode quick enough. You will need to invest in an online double conversion UPS or Isolated online double conversion UPS in order to avoid any downtime. On the other hand if your equipment is a very basic computer workstation with approximate transfer time of 10 milliseconds, you can use the line interactive UPS system with peace of mind that your equipment is protected.

Transfer time is definitely one of the things you need to keep in mind while searching for suitable UPS. More factors affecting your choice of UPS technology are covered in this article.

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Tips How to prevent premature UPS battery failure

Battery

UPS Battery

 

Did you know that majority of UPS’s trouble shootings are battery related? Typical life span of UPS internal batteries ranges from 3 to 5 years; however this depends on numerous factors. Here are a few easy tips to ensure that you get the most out of your batteries and therefore your UPS system:

 

 

Selecting the correct UPS technology:

Uninterruptible Power Supply systems operate in battery mode in two major situations: if the power goes off, or if the mains power input goes out of tolerance. This could mean for example too low or too high voltage, or frequency anomaly (e.g. running off a generator). Some UPS technologies can provide wider input voltage and/or frequency window, which resolves this issue. Example of such technology is online UPS technology – for example our VFI series. Selecting the correct UPS technology for your equipment will ensure the UPS only works off battery in case of emergency. This will prolong the battery’s lifetime.

 

Positioning of UPS:

While installing your UPS be sure to take into account the following factors: your Uninterruptible Power Supply system should be positioned in temperature stable, dry environment. Position your unit so that all ventilations and fans are clear to prevent overheating. The environment should be clean and dry, with no excessive dust or corrosive fumes. If you require the UPS system to be located outdoors, use appropriate storing cabinet – for example our Willo. Small cupboards or other enclosed spaces other than the ones specifically designed for such purposes with ventilations and cooling technologies are not suitable for storing your UPS system.

 

Temperature:

Although specifications for Uninterruptible Power Supply systems usually state temperature between 0°-40°C, it is ideal to keep the ambient temperature between 20 °– 25°C. This will ensure that the UPS will function properly and the battery won’t deplete due to the heat. High temperature drastically reduces battery life – essentially for each 10°C over 30°C, battery life halves. In extreme cases the batteries may start swelling due to a thermal runaway. To prolong battery life, aim to keep your UPS system in an environment with temperature between 20°-25°C.

 

Use of UPS:

The way you use your UPS can have a huge effect on your UPS’s battery life. We recommend that during a power cut you never leave your UPS battery to completely deplete to 0%. Power cuts are usually momentary in which case you don’t need to worry about this, but if you suffer from frequent and prolonged power outage, you should take the time to switch off your equipment and then turn off the UPS to ensure that the batteries don’t deplete completely if possible. Please note that batteries only have so many charge-discharge cycles which are higher the less the battery is discharged. If you don’t discharge to zero you will get more cycles out of your batteries.

 

Storing UPS:

Should your UPS not be in use for a long period of time, we strongly recommend to charge the batteries before storage. Never leave a UPS disconnected from mains for a long period in a discharged state.

 

Service:

A battery service after few years of use is a necessity to ensure that your UPS is functioning correctly. For more information read our previous blog post about our UPS battery services.