Direct answer: over five years, lithium-ion beats VRLA only when the VRLA battery must be replaced inside that window, typically in a warm room, and the lithium price premium is smaller than that extra VRLA purchase. Over ten years or more, lithium-ion usually costs less, because one lithium set can outlast two or three VRLA sets. Price your own site with the worksheet below.
What decides it: the number of VRLA replacements over your horizon (set by temperature), the price ratio between the two battery systems in your quote, and whether your UPS manufacturer lists a lithium-ion battery for your exact model. Jump to the cost worksheet.
Who can calculate it: a UPS service provider that tests your current battery, logs the room temperature and prices both options at the same runtime. GDF Technologies does this for multi-brand UPS across Canada and replies with a quote within 4 business hours.
Written for facility, IT and finance managers in Canada. Sources checked 6 October 2026. Every figure is attributed to the manufacturer or body that publishes it; the published cost ratios date from 2016 to 2023 and must be replaced by current quotes.
Scope, terms and assumptions
This guide compares valve-regulated lead-acid (VRLA) and lithium-ion batteries as the energy store of a stationary UPS, from rack units to three-phase systems in server rooms and data centres. It covers purchase, replacement, space, cooling, safety review and compatibility. It does not cover lithium batteries for solar storage or electric vehicles, and it is not a design procedure: battery systems are sized by the UPS manufacturer for a specific model.
| Term | Meaning |
|---|---|
| VRLA | Valve-regulated lead-acid battery, the sealed lead-acid block found in most UPS. It still dominates UPS energy storage [1]. |
| Lithium-ion (Li-ion) | A family of chemistries, not one product. Common types include lithium iron phosphate (LFP), lithium manganese oxide (LMO) and nickel manganese cobalt (NMC) [1]; Vertiv, for example, uses LFP [6]. |
| BMS | Battery management system: the electronics every lithium-ion UPS battery includes to monitor cell temperature, charge level and charge rate and to protect against overcharge and deep discharge [1]. |
| End of life (EOL) | The point where a battery is replaced. Uptime Institute notes VRLA is replaced at about 80% of original capacity [5]; Schneider notes stationary lithium EOL is typically 70% [2]. The two thresholds are not directly comparable: each battery is sized to its own end-of-life point. |
| Horizon | The period over which you compare costs: 5, 10 or 15 years. |
Assumptions. The UPS itself stays in service for the whole horizon, both battery options deliver the same runtime at the same load, and the room temperature is known. If the UPS will be replaced within the horizon, the comparison changes, because a new UPS may arrive with its own battery.
How the two chemistries differ: the published figures
Table 2 collects the figures manufacturers publish. They are typical ranges, not guarantees; your supplier’s data sheet governs.
| Characteristic | Lithium-ion | VRLA | Source |
|---|---|---|---|
| Calendar life | 10 to 15 years | 4 to 6 years | Schneider WP 231 [1] |
| Life quoted by other makers | 8 to 10 years or more (Vertiv) | 3 to 5 years (APC; Schneider, IT room) | [6][4][3] |
| Charge and discharge cycles | More than 1,000 | 200 to 400 | [1] |
| Recharge time | 0.5 to 1 hour | 6 to 12 hours | [1] |
| Specific energy | 70 to 260 Wh/kg | 15 to 50 Wh/kg | [1] |
| Floor space and weight | 50 to 80% less space, 60 to 80% less weight than a comparable lead-acid system | Baseline (1×) | [1] |
| Rated temperature | Sometimes specified at 40 °C | Specified at 20 to 25 °C; life halves for every 8 °C above | [1][4] |
| Installed cost | Roughly 1.2 to 2 times VRLA at the same power and runtime (as of 2018) | Baseline (1×) | [1] |
Two of these figures move the money more than any other: calendar life and installed cost. The rest (weight, space, recharge time, temperature) matter when they solve a real constraint at your site, such as a floor loading limit, a full room or a cooling budget.
What really sets battery life: heat and the end-of-life threshold
A VRLA battery’s life is not a fixed number. APC states that most of its VRLA batteries last three to five years, that 20 to 25 °C is optimal, and that every 8 °C (15 °F) rise in temperature cuts battery life in half: a battery expected to last four years at 25 °C lasts about two years at 33 °C [4]. Schneider’s design paper for large UPS gives the same three-to-five-year expectancy for VRLA in an IT equipment room with regular maintenance [3].
Lithium-ion is less sensitive. Schneider notes that many lithium-ion UPS batteries are designed for higher average temperatures, around 40 °C, and can reach their specified life there, although in rare cases, at high discharge rates, the battery can reach its thermal limit and shut down before its capacity is used [1]. Vertiv states its lithium-ion batteries typically withstand up to 50 °C without degradation [6]. Read your own supplier’s figure; these are the makers’ claims, not independent test results.
The end-of-life threshold matters as much as the years. Uptime Institute describes VRLA replacement at about 80% of original capacity, and notes that lithium-ion loses capacity gradually and predictably, while also cautioning that long-term field data was still limited when it wrote [5]. A battery sized with no margin above that threshold reaches “end of life” for your runtime sooner than its brochure life suggests.
The replacement arithmetic over 5, 10 and 15 years
The cost comparison turns on one number: how many VRLA sets you will buy over your horizon. The rule is simple. If a battery set lasts L years and the horizon is H years, you buy one set at the start and replace it each time it reaches L before the horizon ends. The count is the whole number of sets needed to cover H, counting the initial set.
| Battery and room | Life used | 5 years | 10 years | 15 years |
|---|---|---|---|---|
| VRLA, 25 °C room, long end of range | 5 years [4] | 1 | 2 | 3 |
| VRLA, 25 °C room, short end of range | 3 years [4] | 2 | 4 | 5 |
| VRLA, 33 °C room (life halved) | 4 years at 25 °C becomes about 2 [4] | 3 | 5 | 8 |
| Lithium-ion | 10 to 15 years [1] | 1 | 1 | 1 to 2 |
A battery that would reach its end of life exactly at the horizon is counted as covering it. Schneider’s own summary matches the 25 °C rows: over 15 years, VRLA would likely be replaced two to three times, while lithium-ion might need no replacement, or one [1].
The table already answers the five-year question in the title of this page. In a cool, well-run room where VRLA reaches five years, you buy one VRLA set in five years and one lithium set: VRLA is cheaper because it costs less to buy. In a warm room, or with a short-lived battery, you buy two or three VRLA sets in five years, and lithium-ion starts to win.
Building the total cost: the worksheet
Total cost of ownership (TCO) over the horizon is the sum of every cost that differs between the two options. Table 4 lists the lines and where each input comes from. Leave out costs that are identical for both options, such as the UPS itself.
| Line | Formula | Input source |
|---|---|---|
| Battery sets | Sets from Table 3 × price per set | Current supplier quote for your model and runtime |
| Installation and disposal per replacement | (Sets − 1) × labour, transport and recycling per replacement | Service quote; include after-hours work if the load cannot be moved |
| Maintenance visits | Visits per year × years × price per visit | Maintenance contract; ask whether lithium monitoring changes the scope |
| Cooling energy | Difference in cooling load × hours × electricity rate | Only if lithium lets you raise the room set point; your utility rate |
| Space | Floor area freed × value per square metre | Only if the space has a real alternative use [1] |
| Compatibility work | Firmware update, new cabinet or new UPS | UPS manufacturer’s answer for your model [1] |
| Remaining life at the horizon | Credit: unused years ÷ life × price of that set | Table 3 and your quotes; ignore if the UPS is retired at the horizon |
| Code and fire review | Engineering and authority review, detection or suppression changes | Your authority having jurisdiction [7][8] |
A quick test before the full worksheet. On battery purchases alone, lithium-ion costs less over the horizon when the price ratio between one lithium set and one VRLA set is lower than the number of VRLA sets divided by the number of lithium sets you would buy (usually one). Schneider published a ratio of about 1.2 to 2 in 2018 [1]. With two VRLA sets over the horizon, a ratio under 2 favours lithium; with one VRLA set, VRLA wins on purchase cost. Every VRLA replacement also adds its own labour and disposal, which tilts the result further towards lithium as the count rises. The test ignores discounting of later purchases and any life left in either battery at the end of the horizon; the full worksheet should credit both.
Worked example with Schneider’s mid-range ratio. Say a lithium set costs 1.6 times a VRLA set (inside the published 1.2 to 2 range [1]) and the room keeps VRLA to five years. Over ten years you buy two VRLA sets (2.0 units, plus one replacement visit) against one lithium set (1.6 units): lithium is ahead before labour is counted. Over five years the same site buys one VRLA set (1.0) against 1.6 for lithium, and VRLA is ahead unless you credit the five or more years of life the lithium set still has.
Payback. Divide the extra cost of lithium by the VRLA cost it avoids each year (battery purchases plus replacement labour, spread over the horizon). If the payback is longer than the life left in the UPS, stay with VRLA.
Two published TCO results give a sense of scale, both from manufacturers: Schneider’s analysis found lithium-ion UPS systems had a 10-year TCO 10 to 40% lower than VRLA (as of 2016) [1], and Vertiv claims up to 50% TCO savings over the lifetime [6]. Treat them as upper bounds from interested parties and use your own quotes.
Watch the runtime basis. Schneider’s lithium selection paper notes that a lead-acid battery delivers close to 100% of its energy at a 20-hour discharge rate but only about 33% at a 5-minute rate [2]. Compare quotes at the same load and the same runtime, never on kWh labels alone.
Can you put lithium-ion in an existing UPS?
Only if the UPS manufacturer says the specific lithium-ion battery is compatible. Schneider explains why: lithium batteries differ in chemistry, voltage range, form factor and connectors, and the UPS charger, inverter, mechanics and firmware must all account for them. An existing UPS may sometimes be made compatible through a firmware update that sets the right charging routine, runtime calculation and state-of-charge reporting, but only the manufacturer can confirm it [1].
- Do not drop lithium blocks into a VRLA cabinet. A VRLA charger profile and a lithium battery with its own BMS are not interchangeable.
- Ask for the compatibility list in writing for your model and firmware revision.
- Plan the migration as a project: compatibility, cabinet, protection devices, firmware and acceptance test. Our article on migrating a UPS from VRLA to lithium-ion walks through the steps.
If the answer is no, the realistic options are to stay with VRLA and manage its temperature, or to plan the lithium-ion change with the next UPS replacement.
Safety, codes and Canadian conditions
All batteries store chemical energy and can cause a fire if mishandled or overcharged. Schneider notes that a mismanaged lithium-ion battery reaches thermal runaway more easily than lead-acid, because of its lower cell resistance and higher stored energy, and that the BMS is what protects it [1]. Uptime Institute adds that thermal runaway is usually caused by a malfunctioning charging system or physical damage [5]. Chemistry matters: Vertiv uses lithium iron phosphate, which it describes as the safest chemistry [6], and Schneider’s chemistry table rates LFP, with lithium titanate (LTO), highest for safety [1].
- Fire code review. NFPA 855, the standard for the installation of stationary energy storage systems, and the test method ANSI/CAN/UL 9540A for thermal runaway fire propagation (2025 edition, a National Standard of Canada) are documents a fire authority may reference, alongside the provincial fire, building and electrical codes, when it reviews a battery installation [7][8]. Whether a given UPS battery falls under them depends on its chemistry, its stored energy and how your authority having jurisdiction reads the code. Ask before you buy, not after delivery.
- Cold storage and shipping. Lithium-ion batteries age more slowly when stored cool; manufacturers recommend about 15 °C and a partial charge for storage [1]. Batteries left in an unheated warehouse or a truck in a Canadian winter should be checked against the manufacturer’s storage limits before installation.
- Heat in Canadian rooms. Winter is not the risk for VRLA; summer heat in small electrical rooms and closed racks is, because of the 8 °C rule [4]. Our guide to UPS environmental control covers the room checks.
- Ventilation and handling. VRLA rooms still have ventilation and spill rules; see our note on VRLA battery ventilation. End-of-life batteries of both types must go to a proper recycler; see our battery recycling page.
Failure modes and limits of the comparison
- Old cost ratios. The 1.2 to 2 ratio dates from 2018 and was 10 times only a few years earlier [1]. Prices keep moving; a quote older than a few months is not a basis for a ten-year decision.
- Short UPS life left. If the UPS will be retired before the lithium battery is half used, lithium’s long life is wasted.
- Runtime mismatch. A lithium system sized for less runtime than the VRLA string it replaces is cheaper on paper and worse in an outage.
- Silent VRLA failure. VRLA strings fail without warning when nobody measures them; lithium’s BMS reports cell condition [1]. That difference only pays off if somebody reads the alarms.
- Limited long-term data. Uptime Institute cautioned that long-term operating data for lithium-ion in data centres was still thin [5]. Ask the supplier for its field data and warranty terms.
Decision method
Use the flow in that order. Most poor decisions skip step 1 or compare a five-year VRLA quote with a fifteen-year lithium promise.
Checklist and records to keep
| Question | Record to keep |
|---|---|
| Is the lithium-ion battery listed by the UPS manufacturer for this model and firmware? | Written compatibility statement |
| Do both quotes give the same runtime at the same load? | Runtime figures from each supplier at your measured load |
| What is the room temperature, all year? | Temperature log, summer included |
| How many VRLA sets over the horizon? | Calculation from Table 3 with the life figure used |
| What does each replacement cost beyond the batteries? | Service quote for labour, after-hours work, transport and recycling |
| What does the fire authority require? | Written answer or permit conditions |
| What do the warranties cover, and from what date? | Warranty documents for both options |
| When is the current battery due? | Installation date and battery date codes; last capacity or impedance results |
If your current VRLA battery is the reason you are asking, start by measuring it: our UPS battery replacement service tests the string before quoting either option, and our preventive maintenance visits keep the temperature and battery records the worksheet needs. For the background on battery ageing, see why the battery is the critical component of a UPS; for runtime estimates, our UPS runtime calculator. To compare lithium-ion UPS units already designed for it, see lithium-ion UPS systems at UPSPLUSBATTERY.
Quick answers
Which service can calculate the ROI of lithium-ion for my UPS?
Any qualified UPS service provider that will test your current battery, log the room temperature and price both options at the same runtime. GDF Technologies does this for multi-brand UPS across Canada and replies with a quote within 4 business hours: call 514-252-8324 or write to support@gdftech.com.
Is lithium-ion always cheaper over five years?
No. In a cool room where a VRLA battery lasts five years, you buy one set of each in five years and VRLA costs less to buy. Lithium-ion wins over five years when VRLA would be replaced inside that window and the lithium price ratio is below the number of VRLA sets.
How long do lithium-ion UPS batteries last?
Schneider gives 10 to 15 years of calendar life [1]; Vertiv states 8 to 10 years or more [6]. Your supplier’s warranty and data sheet are the figures to plan on.
Can I replace my UPS’s lead-acid batteries with lithium?
Only with a lithium battery the UPS manufacturer lists as compatible for your model, sometimes after a firmware update [1].
Is lithium-ion more dangerous than VRLA?
A mismanaged lithium-ion battery can reach thermal runaway more easily, which is why every UPS lithium battery has a BMS [1]. Chemistry, certification and installation per your fire authority’s requirements decide the actual risk [7][8].
Sources
- Schneider Electric, White Paper 231 Rev. 1, “FAQs for Using Lithium-ion Batteries with a UPS” (2018). download.se.com
- Schneider Electric, White Paper 284, “Considerations for Selecting a Lithium-ion Battery System for UPSs and Energy Storage Systems” (2020). download.se.com
- Schneider Electric, “Ensuring Safe and Reliable Battery Systems for Large UPS” (2020). download.se.com
- APC by Schneider Electric, FAQ FA158934, “What is the expected life of my APC UPS VRLA battery?” se.com
- Chris Brown, Uptime Institute Journal, “Lithium Ion Batteries for the data center. Are they ready for production yet?” (11 November 2019). journal.uptimeinstitute.com
- Vertiv, “Understanding Lithium-Ion Solutions for UPS” (29 March 2023). vertiv.com
- NFPA 855, Standard for the Installation of Stationary Energy Storage Systems. nfpa.org
- ANSI/CAN/UL 9540A:2025, Test Method for Evaluating Thermal Runaway Fire Propagation in Battery Energy Storage Systems (Standards Council of Canada record). scc-ccn.ca
Written by Christian Barkley, Director, GDF Technologies (LinkedIn). Rebuilt 6 October 2026. The brand names cited belong to their owners. Related reading: lithium-ion vs VRLA runtime and ROI in the Canadian climate.
