Lithium-ion battery FAQ

Lithium-ion UPSs represent a significant progression in UPS battery technology, which for decades has been dominated by valve-regulated lead acid (VRLA). Because lithium-ion batteries offer a 10- to 15-year lifespan—as opposed to their lead acid counterparts, which generally need to be replaced every 3 to 5 years—the technology offers a number of advantages. 

Which of Eaton's UPSs are compatible with lithium-ion batteries?

Eaton currently has three UPS families that are compatible with lithium-ion batteries. For installations under 20 kVA, Eaton has two models of the 5P UPS: 5P1550GR-L and 5P15500R-L. Eaton's 93PM UPS is compatible with lithium-ion batteries for installations between 20-400 kVA. For installations over 400 kVA, any of the UPSs within the Power Xpert 9395 UPS family are available with lithium-ion batteries. 

Launching soon: Eaton will soon be releasing a lithium-ion 9PX UPS sku. 


What are the primary benefits of switching to lithium-ion UPS batteries?

The most common reason cited by our customers is the significantly longer service life. With lithium-ion, IT professionals can easily deploy lithium-ion UPSs without the maintenance and refresh challenges of those utilizing traditional lead acid batteries. The extended battery life enables users to align their UPS refresh cycles with the rest of IT stack, saving time and money spent on labor and battery replacement. This “set it and forget it” value proposition is especially conducive at sites where operations are critical yet IT resources are constrained. Lithium-ion also provides a greater cycle life (the number of charge/discharge cycles ranges from extends into the thousands, versus approximately 500 for VRLA batteries), as well as a longer standard warranty. Additionally, lithium-ion UPSs can provide more runtime in the same footprint without the need for external battery modules (EBMs). Many customers have also found the lighter weight of a lithium-ion to be an added benefit.

What are some of the downsides of lithium batteries compared to VRLA?

The primary downside is that because the technology is so new, many manufacturers have limited experience in UPS applications. However, this is changing rapidly, with successful deployments now exceeding four years. 

Do lithium batteries pose a higher fire risk than VRLA batteries?

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-ion 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.

Are lithium-ion batteries more expensive?

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. In addition, Eaton requires a customer service engineer to be on site for large battery cabinet startup service, which isn’t needed for VRLA batteries. 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. 

What is the cost per kWH of lithium-ion batteries compared to VRLA batteries?

The cost of lithium-ion battery systems for UPSs have plummeted 50-75% over the last four years. Today, if we compare the cost of a VRLA battery system with a monitoring system and a lithium-ion battery system with the required battery management system (BMS), the cost per kWh is comparable and, in some cases, is even less. Currently, though, the initial setup costs associated with lithium-ion – including freight from South Korea to the United States and additional field service set up and commissioning costs – can drive the cost up to 1.25x the cost of a VRLA battery system. The ten year service life of lithium-ion batteries negates most of those extra costs. 

Can lithium be mixed with other types of batteries (for example, VRLA)?

No, lithium cannot be put in series or parallel with other types of batteries.

Does Eaton see lithium-ion fully replacing traditional VRLA batteries?

Eaton is launching the 9PX 1-3kVA lithium-ion UPS, becoming the 1st UPS vendor to launch a global double conversion offering, because we believe in lithium-ion technology. However, we do believe there will continue to be places where VRLA is more appealing and expect to offer a balance of VRLA and lithium-ion solutions even as we continue investing in longer life battery solutions. 

What else can a UPS system do with the addition of lithium-ion batteries?

With lithium-ion, UPS operators can play a role in helping energy providers balance power generation and consumption with the EnergyAware solution. EnergyAware enables facilities to support sustainable energy solutions, optimize the cost of powering their buildings and create additional revenue streams from their power protection assets.

I like the benefits of lithium ion for UPSs but how do I make sure it’s the right investment for me?

The longer lithium-ion battery life of the UPS—2x battery life vs VRLA—can eliminate the cost of procuring replacement batteries as well as the labor cost for in-person battery replacement. So while it is true the capital expenditure is higher for lithium ion, the lower OPEX costs can offset the up-front investment for many customers. 

Are there small office/rackmount UPS lithium-ion battery solutions available now on the market?

Yes, office-sized UPSs with lithium batteries are now available. They are dramatically lighter than UPSs with VRLA batteries and the battery will typically last the entire life of the UPS. Eaton offers several models of small office UPSs and rackmount UPSs with lithium-ion batteries: 5P1500R-L (120V 1440 VA), 5P1550GR-L (208V 1550 VA) and, launching soon, a 9PX lithium-ion UPS.

Can I replace a VRLA battery system with a lithium-ion battery system?

Yes, Eaton offers lithium-ion battery retrofit systems, which include new cabinets and batteries, for several of our UPS products. The field engineer will need to make minor firmware modifications to the UPS. We cannot, however, deploy a mix of VRLA and lithium-ion batteries for the same UPS system. 

Are lithium-ion UPS batteries safe?

Yes, we are comfortable and confident that all the vendors’ products we offer are safe, when used with our UPS, installed per the manufacturer’s recommendations, and when their environmental requirements are observed. The battery management system (BMS) is one component which ensures the safe operation of the battery, by monitoring temperature, voltage balance, etc., and it has the ability to disconnect the battery string if conditions warrant. The other component is the design of the battery cells and battery modules. All of our vendors comply with UL1642 (Battery cell safety); UL1973 (Battery module/cabinet safety). The BMS complies with UL1973 which pulls in UL991 and UL1998 (Software safety) as appropriate

Have Eaton lithium-ion UPSs experienced any battery failures or fires?

At this time, no UPS manufacturer has suffered a thermal event with its lithium batteries. The presence of a BMS has been instrumental in the detection and mitigation of any anomalies. While we have seen individual batteries fail to retain a charge, these rare instances were not thermal-related and occurred only after we abused the batteries in our lab with stress testing. When the individual cells were replaced, the system operated correctly.  

Where are Eaton’s safety data sheets (SDS)?

You can view the SDS for Samsung lithium-ion batteries here. 

You can view the SDS for LG Chem lithium-ion batteries here. 

Is there any increased risk with thermal runaway lithium-ion vs lead acid?

No, there is not an increased risk. An excert from an application note on lithium-ion battery safety explains "As part of DOT/UN38.3 testing, the case temperature of cells may not exceed 170 °C(338F); since the LFP(Lithium iron phosphate) cells used in the 5P 1U lithium-ion UPS have a thermal runaway point much greater than this temperature, risk of thermal runaway when exposed to situations like the test conditions is further reduced.” 

Read the full lithium-ion UPS battery safety application note here.

How is thermal runaway detected and mitigated?

The battery management system (BMS) and battery module construction handles the detection and mitigation and meets code requirements. The BMS can disconnect the string via shunt tripping the cabinet breaker.

What type of gas do lithium-ion UPS batteries give off?

Lithium-ion UPS batteries do not give off any gas during normal charging/discharging. 

What gasses are vented from Eaton lithium ion batteries during a thermal runaway event?

We have material safety data sheets (MSDS) and UL9540A test reports that show gasses are only released during a fire. 

Download the MSDS for Samsung lithium-ion batteries and LG Chem lithium-ion batteries. 


What is the difference between an active battery management system (BMS) and a passive BMS?

An active BMS has the ability to physically/electronically disconnect either individual batteries or battery strings if thermal or cell balance conditions require intervention by the BMS control. This would happen only after an early warning and shutdown imminent alarms and warnings are issued. A passive BMS is only a monitor. It can issue alarms, but cannot take any protective action on its own. 

Why is a battery maintenance system (BMS) required when deploying a lithium-ion battery bank?

A battery maintenance system (BMS) provides a necessary level of safety against thermal runaway events. 

Is a BMS required by code on all lithium-ion UPS battery installations?

Yes, and it must be listed to UL1973. All Eaton-supplied cabinets are listed.

How does the lithium Battery Management System (BMS) compare with a traditional Battery Monitoring System, like Cellwatch, for example?

Lithium battery management systems and battery monitoring systems, like Cellwatch and BTech, have the following similarities:

  • Both monitor individual battery voltages and string currents
  • Both provide instantaneous status of individual batteries
  • Both (can) monitor battery terminal temperature and cabinet ambient temperature and can warn of possible thermal runaway conditions

Lithium battery management systems differ from Cellwatch/Btech, in the below capabilities:

  • Lithium Management systems ‘manage’ the battery and can take action independently of customer interaction. For example, the BMS can disconnect the entire lithium battery string (cabinet) from the UPS if determined to be necessary and can do this without the client’s permission or acknowledgement.
  • Lithium BMS systems also track and manage individual pack DC voltage balance to limit potential for development of thermal issues.
  • Lithium BMSs lack a user-friendly HMI interface/display. Modbus information to the site’s Building Management System (also called BMS) has to suffice.
  • Lithium BMS tracks voltage, current, temperature, balance voltages constantly for every battery. It communicates status changes and alarms immediately to the UPS, which can then send this info onto the client’s network via the PXGX card. But the information history is not logged in the lithium BMS.

What happens if a lithium-ion battery management system (BMS) fails?

If the BMS fails, stops operating or loses power for any reason, the cabinet or battery string will disconnect from the associated UPS. 

How does a battery management system (BMS) function during a wide imbalance of the internal cabinet temperature for each lithium-ion battery?

The BMS will use the UPS charge voltage to balance the cell, similar to how we do with an equalize charge on flooded batteries.

How long is a lithium-ion battery expected to last in a UPS application?

Eaton’s vendors expect 10-15-year float service life like we utilize in our UPS equipment. Both vendors offer a 3-year defect warranty and a Performance warranty of 10 years.

What is the shelf life of lithium-ion batteries before they need to be checked or charged?

If the lithium-ion 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: Samsung requires a "voltage check" of the batteries every 180 days during storage.

Are there different recharge rates between lithium-ion and VRLA batteries?

Lithium batteries can be recharged significantly faster than traditional 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.

How long does it take to return a lithium-ion UPS battery to 90% capacity after a discharge?

At the vendor-specified recharge currents, it should take no more than 4 hours.

What are recycling protocols regarding lithium-ion vs lead acid?

Eaton has partnered with Call2Recyle to lead the charge in recycling end-of-life battery packs. We provide consumers across North America the capability to do the right thing and conveniently recycle used lithium-ion batteries versus throwing them in the landfill.

Do lithium-ion batteries have recycling and/or disposal issues?

Lithium-ion batteries are disposable and, while currently not readily recyclable, new options are expected in the future. To read more about recycling lithium-ion batteries, visit Eaton's battery recycling page. 

Are there kWH capacity restrictions for lithium-ion battery installations?

Yes. IFC 1206 and NFPA 855 state that maximum allowable quantities are 600 kWH per room, unless the room is specifically built for H2 Hazard Class occupancy. This can be waived by the Authority Having Jurisdiction (AHJ) in the presence of UL9540A test results and a FEMA analysis by engineers designated by the building owners.

Is there any difference between sizing a lithium-ion battery compared to VRLA or NiCd technology?

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. Eaton’s published battery time tables for our UPS products take this into account, and our application engineers are trained on proper sizing of these batteries. As always, feel free to contact Eaton for sizing guidance.

Are there any issues with recharge current after an EOD due to lower resistance in lithium-ion batteries?

At this time, Eaton uses vendor-specific battery charge current limits for lithium-ion UPS systems. These are expected to change over time as we deploy more lithium-ion batteries in traditional UPS system applications and, therefore, gain more data to base our battery charge current limits on. For now, the vendor-specific limits represent a pretty conservative estimate.

Should recharging lithium-ion UPS batteries be delayed after a full discharge?

No. We have limited the charge current per cabinet to a level that will not add internal heating to the battery, thus we can begin recharging immediately upon return of input power.

Can the lithium-ion UPS batteries be charged by the PhotoVoltaic (PV) system, assuming the current is suitable? If not, what other back-up method would you suggest?

We recommend that the PV system, most commonly known as a solar power system (and its inverter) be fed to the UPS input so the UPS directly controls the battery recharging.  In the future this may not be necessary, but currently it is important to have control over the rate of charge for the UPS batteries.

Do lithium-ion batteries work with Eaton ABM?

ABM is not needed with lithium-ion batteries. The purpose of ABM is to extend the service life of VRLA batteries, and since lithium-ion already has an excellent service life characteristic, there are no immediate plans to use it. 

Are the float charging requirements for new lithium-ion battery cabinets different than those for older UPS systems with VRLA batteries or flooded cell batteries?

Yes. The float voltages and ranges for lithium-ion batteries are slightly different. This is handled by a trained CSE in the UPS firmware settings at the startup time. 

What are the BTUh numbers when float charging lithium-ion UPS batteries?

See the Eaton customer drawings for BTUh levels. This heat is negligible. 

Download the Samsung lithium-ion drawing here. Download the LG Chem lithium-ion drawing here. 

What are the BTUh levels during discharge of lithium-ion UPS batteries?

Worst case, 8900 BTUh for Samsung, and only during the duration of the discharge. We do not have this value for LG Chem, but it is expected to be similar.

Why is electrolyte weight important for lithium-ion batteries for UPSs?

Building Codes require the room to become ‘incidental occupancy’ with 1-hour separation rating for the lithium ion/UPS battery room, if total electrolyte weight is >1000 lbs. The battery room shall not be more than 10% of the total building area, in the story they are located. 

What is the electrolyte weight of Eaton’s lithium cabinet systems?

Model Weight
Samsung 136 120 lbs
Samsung 128 113 lbs
LG Chem half cabinet 51 lbs
LG Chem full cabinet 102 lbs

How are lithium-ion UPS batteries shipped? Can they be air shipped?

We will ship battery cabinet systems by ground. Individual replacement batteries may be air shipped. Refrigerated ground shipment is not required for either vendor. Shipments must be in accordance with UN38.3 requirements. All shippers must be trained on Class 9 shipment of hazardous goods. These requirements involve specific packaging, labeling of said packaging, and accompanying paperwork. Trucker and the truck must be certified with proper signage. Batteries for air shipment must not exceed 30% state of charge (SoC). We will ship all lithium batteries at 30% SoC, whether ground or air shipment. It will require about 4 hours of charge time to bring the newly replaced battery up to full charge Battery cabinet systems are shipped disassembled. All assembly and start-up/commissioning activities are included in our pricing.

What are lead times for UPSs with lithium-ion batteries?

4 to 6 weeks from stock (systems must be kitted prior to shipment)

Can copies of Installation and Operators’ Manuals be provided in advance?

Yes, these are available in advance for Eaton sales support. However, they may not be shared. The vendors’ intent is that the user utilizes only the up-to-date manuals that ship with their cabinets. Eaton’s customer installation drawings can be shared at any time. They are posted for both vendors on the SalesWeb. Eaton’s Guide Form specifications can be shared at any time. Guide specs and Eaton customer drawings for both vendors are available on the SalesWeb.

Can the lithium-ion battery cabinet communicate over the network?

Yes, both vendors’ lithium-ion UPS battery cabinets communicate by Modbus TCP. The customer’s connection is via a TCP/IP (RJ45) connector from the bank battery BMS module on either vendor’s cabinet/system.

NOTE: The Modbus TCP provides no alarm history. Information is real time, unless the user creates an external logging program.

Will PredictPulse eventually be connected to lithium-ion battery cabinets?

Yes. Eaton is working to make lithium-ion UPS battery cabinets compatible with PredictPulse monitoring service, with all pertinent information and data monitored and logged.

Is user monitoring software available for lithium-ion battery cabinets?

No, clients must use Modbus TCP which is built-in for both vendors.

How do Eaton systems deal with dendrites in lithium-ion batteries?

The lithium cells in our lithium-ion battery units are composed of LFP (lithium iron phosphate). Each cell includes built-in over charge protection, pressure vent, anti-puncture ceramic coating, and a barrier on the positive LFP electrode to help mitigate short circuiting from any dendritic growth.  Also, our BMS monitors and controls every cell within the battery pack to mitigate conditions which may encourage dendrite growth.

For more information on dendrites in lithium-ion batteries, read Eaton’s latest application note. 

What is max room temperature for lithium battery UPSs?

Operating temperature range: 32 to 104°F / 0 to 40°C 

Which lithium-ion UPS battery vendors do we offer?

Eaton currently offers Samsung and LG Chem lithium-ion batteries. Samsung cabinets containing 128 or 136 battery cells (16 or 17 battery modules). LG Chem cabinets populated with a single string or a double string of battery modules.

What are the major differences between each manufacturer’s lithium-ion batteries?

Manufacturer kWh capacity Seismic zone Power source

32.6 kWh for 128S

34.6 kWh for 136s

Zone 3 for white cabinet

Zone 4 for UL9540A black cabinet

3 phase 400-480Vac


LG Chem

14 kWh for single string

28 kWh for double string

Zone 4 1x 120-240Vac single-phase

Is Eaton looking at additional vendors for lithium-ion battery products?

Yes, and evaluations are underway.

What is the vendor’s warranty?

Each vendor’s warranty document is slightly differently worded, but they each provide: 3 years full parts warranty, and a 10 year “Performance Warranty” on the lithium battery’s ability to provide rated capacity. Administration of the vendor’s warranty will be identical to what we now do for VRLA.

What is the lithium-ion UPS warranty?

Eaton stands behind our lithium technology and the promise of a lower TCO (total cost of ownership). That is why standard warranty for the 5P lithium-ion UPS and the 9PX lithium-ion UPS is 5-years including electronics and battery. Check your local Eaton warranty terms or agreements as warranty may differ in some countries. 

What is a performance warranty?

The vendor warrants that when the battery is installed per vendor’s instructions, operated within vendors environmental guidelines, and charged by the UPS as specified, the battery system will provide at least 78-80% of its initial capacity at the 10-year mark. If the battery or string fails to provide that capacity, it will be replaced at no charge. Labor is not covered, but a labor charge can be added to a battery system quote. The battery must be operated within the environmental specifications and cycle life limits set by the battery vendor. Data recordkeeping is the responsibility of the user (like VRLA). If the evidence indicates that the battery has been misused:

  • Samsung may cancel the 10-year warranty
  • LG Chem decrements the warranty coverage time length, depending on the degree of misuse (temperature and/or cycle count)

For Samsung lithium-ion batteries, what are common installation issues?

Refer to the installation manual part # 164000729, shipped with each cabinet.

  • Control Power: Each cabinet has landing terminals for 2 sets of 480VAC, 15A 3-phase power, or 2 sets of 1-phase 120/240VAC. This is necessary to power the BMS and other controls. Minimum requirement is to provide a single, protected (derived from the UPS output), 480V feed (120/240V feed, if powered by a 208VAC UPS). An additional 480V or 120/240Vfeed, from the UPS bypass source is recommended but not required. For 208VAC UPS, the conduit landing kit (below) includes step-up transformers. NOTE: for newer Samsung cabinets that are black in color, the step-up transformers are no longer required. A single phase 120 or 240VAC feed derived from the output of the 208V UPS connects directly to a terminal block in the conduit landing kit.
  • Conduit landing kit: This top-mounted landing kit is installed by the contractor and contains terminals for both DC power and control/status communications wiring. The installation instructions are provided, document part # P-164000742.
  • Remote trip of the battery cabinet breaker: note that the UPS does NOT generate the shunt trip command for battery breakers. (a UPS “load off” or UPS EPO command will shut off the UPS but will not trip the battery breakers in the Samsung cabinets). The user is responsible for providing a switch or dry contact that must close for 3 seconds to facilitate a remote shunt trip of the battery cabinet breaker. See the installation manual and the customer drawing #110000621 for details of this connection.

For LG Chem lithium-ion batteries, what are common installation issues?

Refer to the installation manual shipped with each cabinet.

  • Cabinet Height: The LG cabinet is 95” tall as shipped. Since the batteries are not installed, the cabined may be moved laying horizontally. Plan for moving this 225lb cabinet through doors, onto small elevators, and note ceiling heights where the cabinet(s) will be placed. Remember that conduit will land on top of the conduit box atop this 100.5” tall cabinet. Commercial/industrial ceiling heights are often 120”, but not always. See customer drawing #110000683 for all dimensions and weights.
  • Wall-mount brackets: The cabinet must be bolted to the floor, by the installing contractor, the wall mounts are not required, but are recommended.
  • Control power: The LG cabinet requires 100V-240VAC single phase power for its BMS and other controls. This power should be ‘protected’, i.e. derived from the UPS output.
  • Remote trip of the battery cabinet breaker: note that the UPS does NOT generate the shunt trip command for battery breakers. (a UPS “load off” or UPS EPO command will shut off the UPS but will not trip the battery breakers in the LG cabinets). The user is responsible for providing +24VDC wiring to each LG cabinet to facilitate a remote shunt trip of the battery cabinet breaker. See the installation manual and the customer drawing #110000683 for details of this connection.
  • Inter-cabinet control wiring for non-adjacent cabinet installations: There is a required inter-cabinet jumper control harness that is supplied but is too short to reach from one cabinet to another when not installed adjacently. Eaton can provide a set of instructions, and parts list for this cable and its end connectors to be assembled onsite. This allows the installer to make a cable with custom length for their specific installation

Why is the Conduit Landing assembly required in lithium-ion UPS battery installations?

Conduit landing provisions are required by code in the US and Canada. Cable may not ‘waterfall’ into the cabinet from above tray, for example. The Conduit landing assembly must be affixed to the cabinet onsite. Instructions are provided. Total cabinet height would be an issue otherwise.

Download installation instructions for lithium-ion battery cabinets.

Which codes apply for lithium-ion battery installations?

It is important to note that Eaton should not be the official source for these answers. Legal liabilities preclude our ability to act as the authority on any of this information. Clients are responsible for interpretation and compliance to the appropriate local codes. However, we do want to provide general information on what clients should be aware of prior to the sale of lithium-ion battery systems. Both national and local codes could apply, and various codes may exceed or supersede our generic interpretations. Codes that may apply are, but not limited to:

  • NFPA 1, section 52.3
  • IFC 1206 2018 edition, formerly section 608 in previous editions. Note that municipalities may not currently have adopted, or even plan to adopt these requirements in the immediate future.
  • NFPA 855 (this will become Article 855 in the 2020 edition of the NEC)
  • California Fire Code: “Blue” supplements, applicable July 2018

The requirements and wording in all the above codes are similar.

Are there Building Code (IBC) considerations for lithium-ion battery installations?

Room location: Not greater than 75’ above or 30’ below the lowest fire department access level unless successful UL9540A testing and FMEA analysis convinces AHJ to approve.

Seismic: Must comply with IBC Section 16, which describes the building structure, not the battery cabinet, but Samsung has been evaluated to seismic Zone 4 with their latest (black) cabinets, available February 2020 and LG Chem has been evaluated to seismic Zone 4.

Ventilation: The below is not different than that which is required for VRLA installations.

  • Maximum gassing is limited to <25% of the lower flammability limit (LFL) of that gas.
  • May require room ventilation or fans which must be remotely monitored
  • Smoke detectors are required.
  • Gas detectors that can automatically start the room fans are required.

What size lithium-ion battery systems must comply with the fire code?

Any battery ‘system’ with capacity greater than 20 kWh must comply with applicable sections of the fire code. Samsung single cabinet is 33 kWh, LG single cabinet is 28 kWh if both strings are present. So, a half-cabinet LG system is only 14 kWh, and technically does not need to comply. That does not mean we can make a system with multiple half-cabinets and avoid the requirements as there are maximum room/building capacities as well.

What fire codes permit indoor installations of lithium-ion batteries?

Previous versions of IFC 608, the new version of IFC 1206 and NFPA 855 all describe how indoor lithium-ion batteries should be deployed. 

What should we know about fire detection and suppression for lithium-ion battery installations?

  • Smoke detectors are required, just like for VRLA.
  • Sprinkler systems (water) are required, as per IFC Sec. 903.3.1.1
  • ‘Clean gaseous’ agents like Novec 1230, FM200, and CO2 systems may be used, but due to their expense, are typically recommended for rooms where water would significantly damage other electrical equipment in the same room such as switchgear or IT equipment.
  • ABC type fire extinguishers are OK if the fire has NOT ‘originated in or spread to’, the battery itself. This does not replace the requirement for water sprinkler systems.
  • Water may be also used to cool the battery and other systems in the same room during a fire.
  • Use the battery vendor’s Safety Data Sheets (SDS) to access instructions for fire suppression.

What is a ‘battery array’ as referenced in IFC 1206 and NFPA 855?

A lithium-ion battery ‘array’ cannot be larger than 50 kWh. Both Samsung and dual-string LG Chem cabinets are considered to be ‘arrays’. If more than 1 of those cabinets are paralleled, it is then the kWh is too large to be a single ‘array’. EXCEPTION: a dual string LG, in parallel with a single string LG (total 42 kWh), is still considered a single array, even though it comprises 2 cabinets.

What are the Maximum Allowable Quantities (MAQ) for lithium-ion batteries referenced in IFC 1206 and NFPA 855?

MAQ for lithium-ion batteries in a room is 600 kWh. If the amount of lithium-ion battery capacity in the room exceeds the MAQ, then ‘Hazardous Class H-2’ room construction is required. This means the room must meet stricter fire rating and other fire and building code requirements. These limits may be waived by the AHJ, but they will need to see the UL9540A test report.

If the capacity of a lithium-ion battery array is less than 20kWh, is NFA 855 compliance required?

No. The minimum threshold for lithium-ion is 20 kWh for both NFA 855 and IFC 1206. 

What is required for lithium-ion battery cabinet (array) spacing?

If the user has adopted the latest fire code IFC1206 or NFPA 855, battery arrays (i.e. each cabinet) must be spaced 3’ apart on all sides from each other and from the walls. That’s 64 sq ft of floorspace, per cabinet. An exception to the rule is for arrays tested to UL9540A. In which case the AHJ can review and accept the test results and can allow that the side and rear spacing is NOT required; only 36” at the front of the cabinet.

To meet NFPA 855 requirements, does there need to be 3’ of spacing on the front and back, and both sides of the lithium-ion UPS battery cabinet?

Yes. There should be a 3’ space from each side of the lithium-ion UPS system.

Has IEEE adopted lithium-ion battery standards?

Not at this time. Eaton has received some specifications that require testing lithium-ion batteries to existing IEEE standards for lead acid batteries, but those standards are not applicable for lithium-ion UPS battery installations. 

Can these limits be exceeded if the system is accompanied by special failure analysis and lab testing?

Yes, if the Authority Having Jurisdiction (AHJ, or electrical/building inspector) approves the analysis and data. Note that the AHJ may be reticent to approve a non-code installation for this relatively new battery application and chemistry. 

Have you heard of any instances where an AHJ did not accept 9540A testing and required the increased 3’ spacing, per their criteria?

Lithium-ion batteries that meet UL9540A standards have only recently become available, so we do not have much anecdotal evidence to draw from. What we have heard is that AHJ have only required the increased 3’ spacing in cases where the room is considered too small or the ventilation capacity is considered too low. 

How does UL9540 apply to UPS applications?

At the moment, we are considering UL9540 listing as applicable to battery energy storage systems (BESS) and not typically applicable for datacenter UPS systems. UL9540 is different than UL9540A.

How do AHJ review the UL 9540A report?

The UPS or battery vendor provides copies of the report, complete with test results and the professional opinion of the UL testers, to the AHJ. 

Have Eaton’s Samsung-built lithium battery cabinets completed UL9540A testing?

Yes. UL9540A is the test method for evaluating the thermal runaway fire propagation in battery energy storage systems. This test is used to evaluate whether a fire or thermal runaway condition in a single battery module or cabinet will propagate outside of the cabinet to adjacent cabinets or walls. Test result data helps the AHJ decide whether battery cabinets may be mounted adjacent or front-to-back with other battery cabinets or the walls of the room. With this test report and the FMEA analysis, the AHJ can waive the cabinet spacing and MAQ requirements for a given installation. The Samsung-built lithium battery cabinets that Eaton offers were tested in accordance with UL9540A and there was no fire propagation outside the module that was being tested. The test report is available to be given to the AHJ. Read more here

What signage is required on lithium-ion UPS battery cabinets?

Eaton-supplied battery cabinets contain the correct signage, including nameplates, per the code Note: other room signage is the responsibility of the site or owner.

How do I verify that my new lithium-ion UPS battery installation complies with relevant safety codes and requirements?

IFC 1206 and NFPA 855 are not retroactive, so installations that took place before they were enacted (in 2018 and 2019, respectively) do not need to comply. New battery installations or expansions of existing ones will need to comply.

To comply, a lithium ion battery installation must meet these requirements:

  • Adequate cabinet spacing or a waiver
  • Not exceeding a max allowable quantity per room of 600kWH
  • Each cabinet, or “array,” should be less than 50kWH
  • Water sprinkler system is installed and functioning
  • Gas detector and smoke detector are installed and functioning, with room fans possibly required for large rooms

Contact an AHJ inspector for any planned new additions. 

Are there any resources available for navigating local regulations on lithium-ion batteries?

Copies of the IFC 1206 and NFPS 855 are available that state the safety of lithium-ion batteries. For help with specific local requirements, you should contact a local authority having jurisdiction (AHJ) at the design and planning stages for a new installation.

Are spare parts recommended for lithium-ion battery installations?

Spares kits are being developed by Service Marketing and New Product Service Engineering.

What parts of the lithium-ion UPS battery installation is handled by the Eaton CSE vs. the electrical contractor?

Contractor places the empty cabinets, secures the battery cabinet to the floor of the building following the installation manual, installs the conduit landing kit, runs wire and conduit for control power (100-120VAC for LG, 480V 3W+G for Samsung), and installs and connects all power and control wiring between the battery cabinets and the UPS. Eaton CSE installs the battery modules in each cabinet, connects the power and communication cabling internal to the cabinet, and performs the battery cabinet software setup and commissioning.

How frequently are Preventative Maintenance (PM) visits recommended for lithium-ion battery installations?

Twice a year. PM procedure includes re-torqueing connections, checking for hot spots, downloading and reviewing real time data from the BMS.

What are the recommended testing protocols to include in 3rd party commissioning of a lithium-ion UPS battery system?

With the absence of a standardized commissioning test for lithium batteries, we expect that commissioning would be somewhat similar to that of VRLA, and should include the following:

  • Verification of correct and safe installation per the vendor’s manuals, including torqueing of terminals and set up of the Battery Management System by a trained service engineer. Configuration files should be saved for future reference.
  • Refresh charge to ensure all batteries in each string are properly voltage-balanced and within limits (this may require several hours of charging). Note that batteries will have been reduced to 30 percent SOC during shipment.
  • Test discharge for time, at one or preferably two different UPS load levels, followed by a review of the BMS data, looking for temperature or voltage anomalies during the discharge.
  • Take time to recharge data and record after a full discharge test.  Verify UPS charge limits are programmed correctly.
  • Verify communication of status, and automatic disconnect device (breaker or contactor) in each cabinet to ensure it is functioning correctly.

What information is required when quoting a field replacement for an existing VRLA installation?

Service Marketing will determine and publish this, but the UPS CTO number, existing battery CTO, available footprint, any weight restrictions, door height, plans for control power and connection to each cabinet’s BMS system, and desired runtime for the new system. User should refer to local and national codes for compliance with lithium ion battery installations. We can advise on typical requirements.

What does the user do if a lithium-ion battery fails in the field?

Call Eaton’s field service dispatch 1-800-843-9433, same as for VRLA.

Can a lithium-ion battery be tested for runtime?

Yes, allow at least 4 hours for charging prior to a discharge test, assuming the batteries are at least 30% state of charge when installed with the UPS.