The most common reason cited is the significantly longer service life. Lithium also provides a greater cycle life (the number of charge/discharge cycles ranges from extends into the thousands, versus approximately 500-600 for VRLA batteries), as well as a longer warranty. Furthermore, the lighter weight and smaller footprint are additional benefits.

In addition, IT professionals can easily deploy lithium battery in UPSs without the maintenance and refresh challenges of those utilizing lead acid. The extended battery life provided by lithium enables users to align their UPS refresh cycles with the rest of IT stack, saving time and money spent on labor and replacement batteries. Furthermore, lithium battery in UPSs boast a “set it and forget it” value proposition, which is especially conducive at sites where UPSs protect critical network operations yet IT resources are not extensive.

The primary downside is that because the technology is so new, many manufacturers have limited experience in UPS applications. However, this is changing rapidly, big battery brands like EverExceed is now coming forward for reliable lithium battery productions.

While any battery has the potential to catch fire if abused, lithium has a reputation for more dramatic ‘thermal events.’ However, in UPS applications, the presence of a Battery Management System (BMS) — which controls charge rate, voltage and temperature — makes lithium batteries less likely to enter thermal runaway than traditional UPS batteries. Additionally, the manufacturing of lithium based UPS batteries is not as restrictive on packaging space as other applications such as cell phone or laptop battery modules, which have appreciably constricted space. UPS manufacturers can utilize the extra space to ensure that the plates inside the battery will not short out, even in extreme conditions. As long as the battery and its packaging are designed to dissipate more heat than can be created on overcharge, the battery cannot go into thermal runaway.  All UPS vendors and battery vendors are ensuring that this is the case for lithium products.

More over EverExceed recommends customer to use LFP batteries over NCM batteries for the UPS application because as per chemical reaction LFP is much safer than NCM. LFP batteries can guarantee you no fire, no explosion.

In general, they vary from slightly more expensive than good-quality VRLA, to two times more expensive, especially when shipping costs and commissioning services are considered. It is important to note that in the near future, when vendors start shipping battery cabinets pre-loaded with batteries, we expect the shipping costs for lithium batteries will actually be slightly less than that of VRLA batteries. Also you need to note that the TCO of lithium batteries are much more less than the VRLA batteries, and within a few year you will gain much more from your Lithium battery investment than the VRLA.

Lithium batteries can be recharged significantly faster than traditional VRLA UPS batteries; however, keep in mind that the manufacturers limit the amount of battery charge current that the UPS can supply.  During recharge, the BMS monitors not only voltage levels, but also the internal temperature of each individual lithium cell. In this manner, the system will automatically limit the charge if a cell gets too warm, which can potentially lengthen the recharge time. In general, the VRLA rule-of-thumb of “10x the discharge time to 90 percent capacity” may not apply to lithium.

If the battery modules are connected together, i.e. installed in a cabinet, the storage times are six months at 25 degrees C. This is due to parasitic losses from the BMS.

If the battery modules are NOT connected together (either power or communication connections), then the storage times are one year at 25 degrees C.

Note: It is recommended to do a "voltage check" of the batteries every 180 days during storage.

Yes, the sizing is slightly different and in the case of lithium, we limit the backup time based not only on low cell voltage limits, but also the cell temperature during discharge.  This means the cutoff time for a lithium battery might be dictated by high temperature, as opposed to only low voltage. As always, feel free to contact EverExceed for sizing guidance.