This Is The Age Of The Lithium UPS

This Is The Age Of The Lithium UPS

Introducing the new range of KR-RM-LI series UPS, true online double conversion UPS Systems with internal Lithium Ion batteries. Welcome to the new age for UPS.

UPS have traditionally used valve regulated sealed lead acid batteries for energy storage. They are relatively cheap, easy to install and maintain and have a reasonably good energy density. They’ve been the technology of choice for decades now.

However, they do have drawbacks. Probably the biggest of which is heat. The expected life from a lead acid battery diminishes once the temperature exceeds 25°C and this deterioration becomes much more rapid above 30°C.

Damaged Battery

Secondly, like all rechargeable batteries, they have only so many charge/discharge cycles in them. Typically this is 200-300. This is usually more than enough for average use. However if the batteries are called into use daily, then you will find that the batteries are shot in under a year.

Thirdly, they only have a fixed life in any case. This is referred to as the “design life”, and is normally quoted as 5-year or 10-year. However this is assuming the batteries are subject to perfect environment, hardly cycled and continuously float charged. Usually you can expect battery life to be 2-3 years in good conditions and less if the environment becomes warm.

Lastly, although the energy density is reasonable, they are in fact quite heavy. A typical UPS battery block of 12V 9Ah weighs 2.5kg. For a typical 3KVA UPS with a 72V string, this is 18kg of weight just for the battery.

Introducing the New Age of Lithium UPS

Lithium Ion batteries are now ubiquitous in our world. They power everything from smart phones to laptop computers and now even cars. Although there has been a few scares with safety, given the sheer number of batteries out there, the problems have been in fact an extremely small percentage. Notwithstanding that, the safety protocols that are required to be in place now mitigate many of these issues. 

Lithium Ion Battery in UPS

Each battery pack is made up of an number of individual cells. Each cell is produced to high quality standards, and electronic circuits monitor the pack to ensure balance in both charge and recharge in each cell. Signs of thermal runaway cause the pack to be disconnected from source power before any external damage can be caused.

So why use Lithium in UPS

Lithium offers some very compelling advantages over lead acid.

Temperature. Lithium is not affected by temperature in the same way as lead acid.  In fact, our UPS can operate in environments up to 60°C without damage to the lithium battery. This is a clear advantage for Lithium UPS where warm environments may be experienced.

Power Density. Did you know Lithium is the lightest metal? It is item number 3 in the Periodic Table of Elements after Hydrogen and Helium. As a result we can cram in  more battery capacity into our KR-RM-LI Lithium UPS than we could possible hope to achieve with lead acid. Each of our models, 1,2 and 3KVA contain 10Ah batteries of 24V, 48V and 72V and provide 11 minutes of runtime at full load. All in a 2U chassis, and not only that – our 3KVA model weighs only 16Kg. To put into perspective the equivalent 3KVA lead acid provides 3minutes of runtime and weighs 32kg! If you wanted to match the Lithium UPS you would need to add a battery pack making a 4U solution weighing 75kg!

Battery Life. The Lithium battery is good for well over 1000 cycles, meaning that you can charge and discharge it every day for about 3 years before you started to see a degradation in performance. It’s service life is 8years with a typical 10 year life.


Lithium UPS, with the higher power density, gives more runtime in a smaller footprint than the lead acid. This may be a good reason to elect for Lithium, however, if you have the room you could opt for additional battery packs with lead acid. However, when you consider you can get three times the runtime for a third of the weight and rackspace than with lead acid, then the Lithium case again starts to become compelling.

The Lithium UPS is of course more expensive than lead acid, but that is just the up-front cost. Taking a whole-life-cost approach you will find, as some of our customers will testify, the Lithium UPS makes financial sense when protecting an investment which has to last 5 years or more. Being fully guaranteed -including the battery – means there is no need to be concerned with scheduling in a battery replacement midway – or even several times – throughout the equipment life span.

If warm temperatures are expected, perhaps due to restricted ventilation- not just hot summer days- then Lithium really is your only option unless you’re happy to swap out the buckled lead acid blocks. If you’re bundling UPS with equipment to go on a customer site, then Lithium will ensure that you won’t have battery problems down the line.


Finally, there’s a lot of misconceptions about being able to ship Lithium units by air. There are certain guidelines you need to have, and all our units are correctly labelled to allow to be sent by air, so there is no need to discount Lithium for transportation reasons.

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