Molicel P42A 21700 4200mAh 45A Battery
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.application-card h3{font-size:20px;} .p42a-desc .application-card ul{margin:0;padding-left:18px;} .p42a-desc .application-card li{margin:0 0 8px;} .p42a-desc .checklist{margin:0;padding-left:18px;} .p42a-desc .checklist li{margin:0 0 10px;} .p42a-desc .faq-item{border-top:1px solid var(--bs-line);padding:16px 0;} .p42a-desc .faq-item:first-child{border-top:none;padding-top:0;} .p42a-desc .faq-item h3{font-size:19px;margin-bottom:6px;} .p42a-desc .foot{font-size:12px;color:var(--muted);margin-top:12px;} @media(max-width:1000px){ .p42a-desc .kpi-grid{grid-template-columns:repeat(3,1fr);} .p42a-desc .chart-grid,.p42a-desc .two-col,.p42a-desc .three-col{grid-template-columns:1fr;} } @media(max-width:640px){ .p42a-desc{padding:14px;} .p42a-desc .hero{padding:24px;} .p42a-desc .kpi-grid{grid-template-columns:repeat(2,1fr);} } product description Molicel P42A 217004200mAh / 45A High-power 4.2Ah 21700 lithium-ion cell engineered for demanding applications that require high current capability, strong voltage support, and higher energy per cell than typical 18650 formats. 45A Continuous Discharge 4200mAh Typical Capacity 15.5Wh Typical Energy 3.6V Nominal Voltage 21700 Power Cell Unprotected Flat Top 45AContinuous Discharge 4200mAhTypical Capacity 4000mAhMinimum Capacity 10mΩAC Impedance @ 1kHz 4.2AStandard Charge Current 21.7 × 70.2mmMax Cell Envelope Molicel 21700 P42A 4200mAh 45A Battery The Molicel P42A is a high-performance 21700 power cell built for high-drain use cases where current delivery and usable energy must be balanced in a compact cylindrical format. Compared with lower-capacity high-output cells, the P42A offers a useful combination of 4.2Ah typical capacity and 45A continuous discharge capability. In practical design terms, the P42A is best viewed as a power-focused 21700: it delivers more runtime than many pure high-drain cells, while still supporting demanding current draw when the pack is properly designed, cooled, and protected. Brand / Model Molicel INR-21700-P42A Cell Series Molicel Power Cell Cell Type 21700 cylindrical lithium-ion rechargeable cell Typical Capacity 4200mAh / 15.5Wh Minimum Capacity 4000mAh / 14.7Wh Nominal Voltage 3.6V Charge Voltage 4.20V Discharge Cut-Off Voltage 2.50V Standard Charge Current 4.2A CC-CV to 4.2V, 50mA cut at 23°C Standard Charge Time 1.5 hours Continuous Discharge Current 45A Typical Impedance 10mΩ AC at 1kHz; 16mΩ DC at 10A / 1s Charge Temperature 0°C to 45°C Discharge Temperature -40°C to 60°C Energy Density 615Wh/L volumetric; 230Wh/kg gravimetric Dimensions 21.7mm max diameter × 70.2mm max height Weight 70g max Protection No — unprotected flat-top cell Electrical operating envelope at a glance. These quick-reference visuals summarize the P42A’s current capability, voltage window, energy translation, and C-rate interpretation. 1. Current Capability Stack Key current reference points for charging, data-sheet discharge curves, and continuous discharge rating. 45A 30A 20A 4.2A Continuous discharge Data-sheet discharge curve Cycle / discharge reference Standard charge Current (A) 2. Voltage Operating Window Basic per-cell voltage limits used for charger, BMS, and pack design. 2.5V 4.2V Usable operating band Discharge cut-off Charge cut-off Nominal cell voltage: 3.6V 3. Capacity and Energy Translation The data sheet lists 15.5Wh typical energy; nominal-voltage math gives a close planning estimate. Capacity 4.2Ah Voltage 3.6V Energy ≈15.1Wh 15.5Wh typical in data sheet × = 4. C-Rate Conversion For a 4200mAh cell, 1C equals approximately 4.2A. 0.84A ≈0.2C rated / low-rate reference 4.2A 1C standard charge and discharge reference 10A ≈2.4C cycle / discharge reference 20A ≈4.8C high-load reference 30A ≈7.1C data-sheet curve reference 45A ≈10.7C continuous discharge rating High-current output should be evaluated with voltage sag, heat rise, and pack resistance in mind. The P42A’s data sheet includes discharge-rate curves at 0.84A, 4.2A, 10A, 20A, and 30A, while the cell is specified for 45A continuous discharge. This makes it a strong choice for high-drain battery packs, but real performance depends on temperature, cell state of charge, nickel/busbar sizing, weld quality, airflow, and BMS/current limits. The simplified discharge-curve graph below visualizes voltage versus delivered capacity under light, medium, and high-current conditions. It is not a digitized manufacturer curve; it is a product-page visualization designed to show how increasing load increases voltage sag and shortens usable capacity under cutoff-limited conditions. Discharge-rate references 0.84A Low-rate reference curve in data sheet 4.2A 1C discharge-temperature test current 10A / 20A Cycle-characteristics test currents 30A High-rate curve shown in data sheet 45A Specified continuous discharge current Design takeaway For high-current packs, validate voltage sag and cell temperature under the actual enclosure and cooling conditions. 5. Simplified Discharge-Curve Graph Voltage vs. capacity illustration for 4.2A, 20A, 30A, and 45A operation. Simplified for product-page visualization. 4.2V 3.9V 3.6V 3.3V 3.0V 2.7V 2.5V 0 1000 2000 3000 4200 Capacity delivered Cell voltage 4.2A reference 20A high load 30A data curve 45A max cont. 6. Estimated IR Voltage Drop Planning reference using Molicel’s typical AC and DC impedance values. Real pack sag includes cells plus interconnects. V_drop ≈ I × R At 20A and 10mΩ AC reference: ≈0.20V estimated drop At 45A and 10mΩ AC reference: ≈0.45V estimated drop At 45A and 16mΩ DC reference: ≈0.72V estimated transient drop Welds, nickel, busbars, holders, wiring, fuses, BMS MOSFETs, temperature, age, and SOC all influence real voltage sag. Charge, discharge, and thermal behavior should be treated as one system. Molicel’s data sheet includes charge curves, discharge-rate curves, discharge-temperature curves, and cycle-characteristics curves. These visuals are condensed into customer-friendly diagrams below. 7. Charge Profile Reference Standard charge: CC-CV to 4.2V with 50mA cut at 23°C. Data sheet also charts 8.4A charge behavior. 4.2A standard CC stage CV hold @ 4.2V 50mA termination 8.4A characterization curve shown in data sheet Voltage / current Charge time progression Start Constant current Constant voltage 8. Thermal Operating Envelope Published charge and discharge temperature ranges. Charge: 0°C to 45°C Discharge: -40°C to 60°C Upper charge limit Upper discharge limit High-current pack design should include temperature sensing and current derating. 9. Discharge Rate Characterization Customer-friendly summary of the data-sheet discharge-rate curve families. 0.84A / 4.2A 10A 20A 30A Capacity delivered Voltage 10. Discharge Temperature Characterization The data sheet charts 4.2A discharge behavior from -40°C through 60°C. -40°C -30°C -20°C 0°C 23°C 45°C 60°C Higher Lower Relative delivered capacity Test temperature 11. Cycle-Life Visualization Data-sheet cycle characteristics are shown for 10A and 20A discharge to 2.5V at 23°C. 10A discharge 20A discharge 0 100 200 300 400 500 100% 80% 60% 40% Cycle count Capacity retention 12. Energy Density Summary Data-sheet energy density values for design comparison. Typical Energy 15.5Wh Minimum Energy 14.7Wh Volumetric Energy Density 615Wh/L Gravimetric Energy Density 230Wh/kg Design implication Strong energy for a power cell, with significantly higher capacity than many high-drain 18650 options. 21700 dimensional envelope for holders, sleds, weld fixtures, and pack CAD. The product listing uses approximate dimensions, while Molicel’s data sheet provides the maximum envelope. Use the maximum values for fixture clearance, holder selection, and CAD checks. 13. Cell Dimension Diagram Mechanical envelope based on Molicel maximum dimensions. 70.2mm max 21.7mm max 21700 cylindrical steel-can cell with maximum envelope shown Confirm fit in holders, chargers, sleds, welded modules, and insulated pack fixtures. 14. Pack Scaling Formulas Quick math for series/parallel planning. Validate current limits thermally and electrically. Pack Voltage ≈ Series Count × 3.6V Pack Capacity ≈ Parallel Count × 4.2Ah Pack Energy ≈ S × P × 15.5Wh Cell-Level Current Capability ≈ Parallel Count × 45A 15. Example Parallel Scaling Approximate scaling using cell-level continuous discharge rating, not a finished-pack guarantee. 1P 4.2Ah, 15.5Wh, 45A cell-level current reference 2P 8.4Ah, 31.0Wh, 90A cell-level current reference 3P 12.6Ah, 46.5Wh, 135A cell-level current reference 4P 16.8Ah, 62.0Wh, 180A cell-level current reference 5P 21.0Ah, 77.5Wh, 225A cell-level current reference 16. Common Series Voltage Examples Nominal voltage examples only. Full-charge and cut-off pack voltages scale separately. 1S 3.6V nominal / 4.2V full / 2.5V cut-off 3S 10.8V nominal / 12.6V full / 7.5V cut-off 4S 14.4V nominal / 16.8V full / 10.0V cut-off 5S 18.0V nominal / 21.0V full / 12.5V cut-off 10S 36.0V nominal / 42.0V full / 25.0V cut-off 13S 46.8V nominal / 54.6V full / 32.5V cut-off Use the P42A inside a controlled electrical and thermal system. This is an unprotected high-power cell. Safe implementation requires a charger, BMS, fuse strategy, interconnect design, and thermal-management plan that respect the cell’s limits. 17. Suggested Control Threshold Map System-level control guidance derived from the live listing and Molicel data-sheet values. Charge upper limit 4.20V per cell Discharge floor 2.50V per cell Charge temperature gate 0°C to 45°C Discharge temperature gate -40°C to 60°C Standard charge 4.2A CC-CV to 4.2V, 50mA termination Continuous current 45A cell-level rating, subject to system-level thermal and interconnect validation 18. Risk-Control Checklist Recommended pack-building and use practices. Use only in devices or packs designed for lithium-ion 21700 cylindrical cells. Use a BMS or controller that monitors voltage, current, and temperature. Do not charge above 4.20V or discharge below 2.50V per cell. Validate high-current operation under the actual enclosure, cooling, and load profile. Never carry loose cells with conductive objects such as keys, coins, tools, or metal cases. Spot weld for pack assembly; do not solder directly to the cell body. Inspect wraps and top insulator rings before use. Size busbars, nickel, fuses, wiring, and BMS MOSFETs for both electrical resistance and heat rise. Best suited for high-drain systems that need both power and capacity. Power Tools Strong option for tool packs requiring high current per cell. Good balance of output and runtime in a compact 21700 footprint. Drones / eVTOL Useful for high-power airborne systems where current density matters. Thermal validation is essential under peak discharge profiles. E-Bike / Mobility Suitable for performance mobility packs when paired with correct BMS, fusing, and cooling. Parallel count should be based on measured current, voltage sag, and heat rise. Robotics / RC Supports high motor current and compact pack geometry. Useful where power response and moderate energy density are both important. High-Output Lighting Good fit for demanding LED systems that pull high current from each cell. Use only in devices designed for unprotected 21700 flat-top cells. Custom Battery Packs Designed for experienced builders and integrators who can manage current sharing and heat. Requires matched cells, correct welding, insulation, protection electronics, and pack-level testing. 19. Selection Bias: Power vs. Runtime for shoppers comparing high-power and high-energy cells. More runtime per cell → More power / current → Molicel P42A High-power 21700 with strong capacity Higher-capacity energy cells typically sit further right 20. Application Suitability Matrix Simple product-page fit guidance. Power tools Strong fit Drones / eVTOL / RC Strong fit Performance mobility packs Strong fit with validation Runtime-focused electronics Good, but may be more power than needed Maximum runtime per cell Consider higher-capacity energy cells Unmanaged consumer devices Not recommended Safety, Handling & Compatibility Notice This product is an unprotected lithium-ion cell. It should only be used by customers who understand lithium-ion cell safety and who are using the battery in compatible hardware, managed packs, or professionally designed assemblies. Improper use can lead to overheating, venting, fire, or explosion. Charge only with lithium-ion chargers or managed battery systems designed for the correct chemistry and cell count. Never short circuit, crush, puncture, incinerate, or expose the cell to water. Do not use cells with damaged wraps, dented cans, or missing top insulator rings. Do not mix with cells of different age, capacity, model, or state of charge in the same pack. For assembly, use spot welding rather than direct soldering to reduce heat damage risk. Store and transport in non-conductive cases; never carry loose cells in pockets or bags. Keep away from children and from applications for which the product is not specified. Not for e-cigarette, vape, or similar use. Common technical questions about the Molicel P42A. What is the capacity of the Molicel P42A? The P42A has a typical capacity of 4200mAh and a minimum capacity of 4000mAh. The data sheet lists typical energy as 15.5Wh and minimum energy as 14.7Wh. What is the discharge rating? The P42A is specified for 45A continuous discharge. Finished pack current should still be limited by thermal design, busbar/weld resistance, BMS ratings, fusing, and device requirements. Is this a protected battery? No. This is an unprotected flat-top 21700 cell and should be used only in equipment or packs with appropriate electrical and thermal protection. What charger should be used? Use a lithium-ion charger or battery-management system that uses a CC-CV profile to 4.20V per cell. The standard charge current listed by Molicel is 4.2A with 50mA termination at 23°C. Can the P42A fast charge? The product data sheet shows charge-characteristic curves at both 4.2A and 8.4A, while the published standard charge current is 4.2A. For applications using higher charge currents, validate temperature, cycle life, and manufacturer guidance for the complete system. What is the correct discharge cut-off voltage? The data sheet states a 2.50V discharge cut-off voltage per cell. Many pack designers choose a higher system cut-off to reduce stress and improve service life. Can the P42A be used in battery packs? Yes. It is a strong candidate for high-power custom battery packs when cell matching, spot welding, BMS sizing, fusing, insulation, and thermal validation are properly engineered. Can I solder wires directly to this cell? Direct soldering is not recommended. Spot welding is the preferred pack-assembly method because it reduces the risk of heat damage to the cell. What are the cell dimensions? Molicel lists the maximum cell envelope as 21.7mm diameter and 70.2mm height, with a maximum weight of 70g. Always confirm physical fit in the actual device or holder. What temperature range is allowed? The P42A data sheet lists 0°C to 45°C for charging and -40°C to 60°C for discharging. High-current use should include temperature monitoring and derating. Is the P42A better for power or runtime? It is primarily a power cell, but with a strong 4200mAh typical capacity. It is a good choice when both high current and useful runtime are needed in a 21700 format. What does 10mΩ AC impedance mean? It indicates low cell impedance, which helps support higher current delivery and reduced voltage sag. Real pack resistance also includes welds, nickel, busbars, wiring, holders, fuses, and BMS components. How many cycles should I expect? The product listing uses a general 300+ cycle-life description, while the data sheet shows cycle-characteristics curves at 10A and 20A discharge. Actual cycle life depends on temperature, charge voltage, discharge current, depth of discharge, and pack design. Can I carry this battery loose? No. Loose transport is unsafe because conductive objects can short the terminals. Always use a non-conductive battery case.
