For OEM buyers and product engineers, the right choice is not simply “the battery with more mAh.” A cell has to fit the enclosure and holder, remain within the device’s electrical limits, support the real load profile and work with a correctly configured charging circuit. This guide compares the two formats around those practical decisions.

LIR2450 vs LIR2032 Specifications at a Glance

The following figures are from PKCELL’s current product-family table. Individual product pages also show 40 mAh for one LIR2032 SKU and 110 mAh or 120 mAh for LIR2450 SKUs, so procurement and engineering teams should freeze the exact part number and approved datasheet before qualification.

See the individual 40 mAh LIR2032 product page and 120 mAh LIR2450 product page for SKU-level starting points.

Size Difference: What 2032 and 2450 Mean in a Real Design

The model code is a fast size reference, but the approved drawing should control the mechanical design. In PKCELL’s table, the LIR2032 measures 20.0 mm across and 3.2 mm high. The LIR2450 measures 24.5 mm across and 5.0 mm high.

Enclosure and PCB consequences

Moving from LIR2032 to LIR2450 increases the circular footprint by about 50%. When the greater height is included, the simple cylindrical envelope is approximately 2.34 times larger. That can affect more than the holder outline:

• PCB keep-out area and routing around the holder
• Enclosure wall clearance and battery-door geometry
• Spring-contact travel and retention force
• Access for insertion, removal and service
• Product balance, drop behavior and vibration resistance
• Clearance for tabs, leads, insulation and welding features

Electrical similarity does not create mechanical compatibility. A 24.5 mm battery cannot be treated as an upgrade for a holder designed around a 20 mm cell.

If the cell will be welded to tabs or installed as a wired assembly, request the full drawing rather than designing from the bare-cell diameter alone. Explore the broader PKCELL button cell range when an intermediate diameter, lower profile or different chemistry may fit the mechanical envelope better.

Capacity and Runtime: Why 120 mAh Does Not Mean an Exact 2.7x Service Life

Using the family-table nominal values, 120 mAh divided by 45 mAh is about 2.67. Under identical test conditions and the same load, the LIR2450 should therefore offer materially longer time between charges. Yet a direct runtime multiplier is only an early estimate.

Usable runtime depends on the device’s cutoff voltage, continuous and pulse current, temperature, cell age, self-discharge, regulator efficiency and charger behavior. A wireless product may average only a small current but still demand short radio peaks that cause voltage sag. A cell can retain charge while the device resets because the pulse voltage falls below the system threshold.

A better first-pass runtime calculation

Use this screening formula before prototype testing:

Estimated runtime (hours) = usable capacity (mAh) / average load (mA)

Do not automatically use 100% of the nameplate capacity. Apply an engineering allowance for the operating temperature, aging, conversion loss, cutoff voltage and peak-load behavior. Then verify the estimate on production-representative hardware across the expected environmental range.

Electrical and Charging Compatibility

Both products belong to the rechargeable LIR family, and the referenced PKCELL pages identify 3.6 V nominal SKUs while the family table uses 3.7 V. This labeling difference is a reason to approve a precise specification, not a reason to assume that all LIR coin cells share identical limits.

A conventional LIR cell commonly uses a controlled single-cell lithium-ion CC/CV charge profile, but charge voltage, current, termination, temperature limits and protection requirements must come from the exact datasheet. PKCELL’s 40 mAh LIR2032 page lists a maximum constant charge current of 20 mA, while the 120 mAh LIR2450 page lists 60 mA. A charger configured for the larger cell could exceed the smaller cell’s limit.

• Validate the maximum charge voltage and charger accuracy.
• Set charge current for the approved cell, including precharge behavior.
• Check termination at the low currents used by coin cells.
• Control charging outside the permitted temperature range.
• Include standby current from the charger, regulator and protection path.
• Test over-discharge, short-circuit and reverse-polarity risks at system level.

For more circuit-level detail, read the LIR2032 charger guide. If the design may also accept a disposable 2032-size cell, review the separate LIR2032 vs CR2032 compatibility guide; a CR2032 must never be charged.

LIR2450 vs LIR2032 Applications

The best application is defined by the actual duty cycle and available space, not by a generic list printed on a product page. As a practical starting point, LIR2032 favors thin and lightweight designs; LIR2450 favors longer intervals between charges and greater load headroom.

Common application patterns

For a broader discussion of voltage classes and device matching, see PKCELL’s 3.7 V battery guide.

Can You Replace LIR2032 With LIR2450?

Usually not without redesign. The LIR2450 is 4.5 mm wider and 1.8 mm thicker. It will not fit a holder or enclosure built for LIR2032. Even if a wired cell allows mechanical relocation, the charging current, load response, mounting method and safety documentation must be revalidated.

The reverse substitution also needs review. An LIR2032 may fit a redesigned assembly but provides much less capacity and lower representative continuous-current capability. A prototype that powers up is not proof that the smaller cell will meet runtime, pulse-load or cycle-life requirements.

OEM Selection Checklist

1. Define the mechanical envelope: maximum diameter, thickness, holder, tabs, leads and service clearance.
2. Map the load: sleep current, active current, pulse magnitude and duration, duty cycle and abnormal loads.
3. Set the voltage window: maximum input, brownout threshold, regulator dropout and end-of-discharge cutoff.
4. Calculate usable runtime: include conversion losses, temperature, aging and an appropriate margin.
5. Match the charger: verify charge voltage, current, termination, power path and temperature control.
6. Prototype the final system: test with production-representative cells, enclosure, firmware and radio behavior.
7. Qualify supply requirements: confirm part revision, tolerances, certifications, transport documents, lot traceability and change notification.

Frequently Asked Questions

Conclusion: Select the Cell Around the Product

LIR2032 is the stronger starting point for a slim, light product with moderate energy needs and regular charging. LIR2450 is the stronger starting point when the enclosure has room and the product needs more capacity, longer intervals between charges or greater current headroom.

Whichever format looks promising, approve the exact SKU rather than the case name alone. A defensible selection combines the cell datasheet, mechanical drawing, charging design, load profile and tests in the finished product.