10-Pack Vapcell K40 21700 4000mAh 30A CDR Flat Top Battery – High Drain for E-Bike, Power Tools, Flashlights
Description
Description
Unleash relentless high-current power with the Vapcell K40, a top-tier 21700 high-drain cell engineered for the most demanding applications. This 10-pack delivers a true 30A continuous discharge with an ultra-low internal resistance of approximately 9mΩ, virtually eliminating voltage sag under heavy loads. Built on trusted high-drain 21700 technology, it is the definitive choice for high-performance e-bike battery packs, heavy-duty cordless power tools, competition-level , FET-driven flashlights, and RC racing models. The 4000mAh capacity provides a solid balance of runtime and extreme power. The flat top design ensures universal compatibility and simplifies spot-welding for custom battery packs. When your device demands uncompromising current and bulletproof reliability, the Vapcell K40 delivers professional-grade performance every time.
Key Features
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30A True Continuous Discharge (CDR) – Massive, stable current for the most power-hungry devices. Handles angle grinder start-ups, e-bike hill climbs, sub-ohm builds, and hot-rod flashlight turbos without dangerous voltage sag.
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4000mAh Balanced Capacity – Optimized for high-drain applications. Provides solid runtime for demanding use while maintaining full 30A output capability throughout the discharge cycle.
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Ultra-Low Internal Resistance (~9mΩ) – Minimizes heat generation and voltage drop under load, keeping your device cooler and ensuring maximum power delivery from start to finish.
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Flat Top Design – Universally compatible with all standard 21700 spring-contact chargers, flashlights, and battery trays. The flat terminal is ideal for spot-welding nickel strips in custom battery packs.
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10-Pack Bulk Value – Perfect for building a 10S1P 36V e-bike pack, rebuilding multiple tool battery packs, or stocking up for your high-drain device fleet.
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Vapcell Quality Control – Each cell is tested and matched for consistent capacity and internal resistance, ensuring reliable performance across the entire pack.
Parameters
| Parameter | Specification |
|---|---|
| Model | Vapcell K40 |
| Cell Core | High-drain 21700 (Samsung 30T or equivalent class) |
| Typical Capacity | 4000 mAh (0.2C discharge to 2.5V) |
| Minimum Capacity | ~3900 mAh |
| Nominal Voltage | 3.6 V (typical operating 3.7 V) |
| Max Continuous Discharge (CDR) | 30 A (cell temperature ≤ 80°C) |
| Max Pulse Discharge | Up to 40–45 A (short burst, monitor temperature; not for continuous use) |
| Discharge Cut-off Voltage | 2.5 V (do not over-discharge) |
| Standard Charge | CC-CV, 0.5C (2000 mA) to 4.2 V, cut-off 50 mA |
| Max Charge Current | 1C (4000 mA); 0.5C recommended for best longevity |
| Internal Resistance | ≤ 12 mΩ (typical ~9 mΩ, AC 1 kHz) |
| Cycle Life | ≥ 250 cycles (to 80% capacity, 1C charge / 10A discharge) |
| Operating Temperature (Discharge) | -20°C to 60°C (ensure adequate cooling for sustained 30A) |
| Top Type | Flat Top |
| Dimensions | Approx. |
| 21.2 mm diameter × 70.3 mm length | Weight (single cell) | Approx. |
| 68 g | Package Includes | 10 × Vapcell K40 21700 cells in protective packaging |
Applications
Recommended For
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E-Bike & E-Scooter Battery Packs: The 10-pack provides exactly the right number of cells for a 10S1P 36V configuration. The 30A CDR supports powerful 750W–1200W motors, and the 4000mAh capacity delivers solid range. Always use a properly rated BMS.
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Heavy-Duty Cordless Power Tools: Angle grinders, circular saws, impact drivers, and rotary hammers. The 30A continuous rating handles start-up surges and sustained heavy loads with ease. Perfect for rebuilding high-performance tool battery packs.
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High-Power Vaping: Mechanical mods and high-wattage regulated devices running super-sub-ohm builds (safely down to ~0.12Ω at 3.6V). The ultra-low 9mΩ internal resistance ensures instant ramp-up and minimal voltage sag for competition-level performance.
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FET-Driven High-Output Flashlights: Hot-rod torches and multi-emitter custom builds that demand 20–30A on turbo. Enjoy extreme brightness with rock-steady voltage.
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RC Cars, Boats & FPV Drones: Competitive models requiring instantaneous 30A+ bursts. The K40 delivers instant throttle response and consistent power throughout the race.
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Portable Spot Welders & DIY High-Current Projects: Multi-cell configurations deliver enormous short-circuit currents for the most demanding DIY applications.
Not Recommended For
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Long-Runtime Low-Power Devices: Solar lights, camping lanterns, and wireless sensors. These benefit more from a 5000–6250mAh high-capacity cell such as the Vapcell F60 or F63.
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Extreme Competition Vaping (>30A Continuous): Requires 35–45A CDR. Choose the Vapcell T42 (35A) or Molicel P45B (45A) for builds below 0.10Ω.
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Standard USB Power Banks: The extreme current capability is wasted, and the 4000mAh capacity is lower than high-energy alternatives.
FAQ
Q: What cell is under the Vapcell K40 wrap?
A: The Vapcell K40 is based on high-drain 21700 cells such as the Samsung INR21700-30T or equivalent, known for their true 30A continuous discharge and ultra-low internal resistance. Vapcell tests and re-wraps these cells, ensuring consistent performance and authenticity.
Q: Can I use this battery for vaping? What resistance is safe?
A: Absolutely. The K40 is an excellent 21700 cell for mechanical mods and high-wattage regulated devices. With a 30A CDR at 3.6V nominal, it can safely handle builds down to approximately 0.12Ω, leaving a generous safety margin. Always calculate your actual current using Ohm's law and never exceed 30A continuous.
Q: Can I build an e-bike battery with this 10-pack?
A: Yes. The 10-pack is perfectly sized for a 10S1P 36V e-bike battery. For increased range, you can build 10S2P (20 cells) or 10S3P (30 cells). The 30A per cell rating supports motors up to approximately 1200W in a 10S1P configuration. Always use matched cells, spot-weld nickel strips, and install a BMS rated for at least 40A.
Q: Is the 30A rating continuous or pulse?
A: The 30A is the Continuous Discharge Rating (CDR). The cell can handle short pulses up to 40–45A, but sustained operation must stay within the 30A limit. Never design your system based on pulse ratings for continuous operation.
Q: Why choose the K40 over a higher-capacity 21700 cell?
A: The K40 prioritizes current delivery and ultra-low internal resistance over maximum capacity. If your device draws 20–30A, the K40 will deliver more stable voltage and run significantly cooler than a high-capacity cell pushed beyond its limits. For applications drawing under 15A where runtime is the priority, a 5200–6000mAh cell like the Vapcell M52 or F60 would be more suitable.
Q: How should I store these cells when not in use?
A: Store at 3.6–3.7V (approximately 40–50% charge) in a cool, dry place. Use non-conductive battery cases to prevent accidental short circuits. Avoid storing fully charged or deeply discharged for extended periods.
Shipping and Returns
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Free Shipping: Enjoy free shipping on all orders over $65. For orders under $65, the shipping cost is $8.99.
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Delivery Time: Once shipped, orders typically arrive within 7–15 business days.
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Easy Returns: We want you to be completely satisfied. If you're not, you can return your product within 30 days of receiving your order. Please ensure the items are unused and in their original condition. For return instructions, please contact our support team.
Payment & Security
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Security
I rebuilt my cordless impact wrench with these K40 cells. The 30A discharge handles the high torque demands without any issues.
The Vapcell K40 offers genuine 4000mAh and 30A at a competitive price. The 10-pack makes it economical for complete battery builds.
My FPV ground station uses these K40 cells. The 4000mAh provides extended operating time and the 30A handles peak demands.
I ran a discharge test at 30A and the temperature stayed under 60¡ãC. The K40 handles high current with good thermal management.
My Acebeam X80-GT runs on these K40 cells. The 30A discharge handles turbo mode and the 4000mAh gives decent runtime.
Refund Policy
OneAndes Return & Refund Policy
At OneAndes, we are committed to providing high-quality cylindrical lithium-ion batteries for your drones, vacuums, garden tools, and other power needs. If you are not completely satisfied with your purchase, we are here to help. Please read our full return policy below before initiating a return.
1. Return Window
You have 30 calendar days from the date you received your item(s) to request a return. Any return request submitted after 30 days will not be eligible for a refund or exchange.
2. Eligibility Conditions
To qualify for a return, all items must meet the following conditions:
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Condition: Items must be unused, undamaged, and in the same condition that you received them.
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Packaging: Items must be returned in their original packaging with all accessories, manuals, and protective covers intact.
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Proof of Purchase: A valid receipt, order confirmation email, or proof of purchase must accompany all returns.
Non-Returnable Items:
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Batteries that have been installed, used, or show any signs of wear.
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Items marked as “Final Sale” or “Clearance” at the time of purchase.
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Customized or special-order products.
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Gift cards.
If a returned item fails to meet these conditions, we reserve the right to deny the return or charge a restocking fee.
3. How to Initiate a Return
Follow these steps to return your product:
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Contact Us: Email our support team at support@oneandes.com with your order number and the reason for return. We aim to respond to all return requests within 24 hours on business days.
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Receive RMA: We will provide you with a Return Merchandise Authorization (RMA) number and return instructions. Do not ship any item without an RMA number.
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Pack Securely: Place the item in its original packaging, include all accessories, and clearly write the RMA number on the outside of the box.
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Ship to Our US Warehouse: Ship the package to the following address:
OneAndes Returns
10320 6th St
Rancho Cucamonga, CA 91730
USA*Important: Lithium-ion batteries are classified as hazardous materials (Class 9). Please follow the shipping guidelines provided in Section 4 below. We recommend using a trackable shipping service and purchasing shipping insurance, as we cannot guarantee receipt of your returned item.*
4. Return Shipping Costs
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Defective or Incorrect Items: If the item you received is defective, damaged in transit, or different from what you ordered, OneAndes will cover the return shipping cost. In this case, we will provide you with a prepaid return shipping label.
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Buyer’s Remorse / Non-Defective Returns: If you are returning an item for any other reason (e.g., no longer needed, ordered the wrong model), you are responsible for the return shipping costs. You must prepay the return shipping cost using a trackable carrier that accepts lithium batteries. We do not provide prepaid return labels for non-defective returns.
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Lithium Battery Shipping Regulations: By law, all returns must be shipped in compliance with applicable dangerous goods regulations. We will provide guidance on proper packaging and labeling. Failure to comply may result in carrier refusal, seizure, or additional fees. We are not responsible for returned items lost or rejected by the carrier due to improper shipping.
5. Refunds
Once we receive and inspect your return at our Rancho Cucamonga, CA facility, we will notify you via email of the approval or rejection of your refund.
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Approved Refunds: If approved, your refund will be processed to your original method of payment within 5 to 10 business days. Please note that depending on your bank or credit card issuer, it may take additional time for the credit to appear on your statement.
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Partial Refunds: In certain situations, only partial refunds may be granted:
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Items not in original condition, missing parts, or damaged for reasons not due to our error.
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Items returned more than 30 days after delivery (reviewed on a case-by-case basis).
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Non-Refundable Fees: Original shipping charges are non-refundable unless the return is due to our error (defective product or incorrect shipment).
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Restocking Fee: We do not charge a restocking fee for defect-free returns, but we may deduct the return shipping cost, which will be deducted from your refund.
6. Exchanges
We replace items only if they are defective or damaged upon arrival. If you need to exchange a defective item for the same product, please contact us at support@oneandes.com. Exchanges are subject to product availability.
If you ordered the wrong battery size or model, please follow the standard return process above and place a new order for the correct item.
7. Damaged or Missing Items
If your package arrives visibly damaged, please take photos of the package before opening and contact us immediately. We will work with the shipping carrier to file a claim and arrange for a replacement or refund. Damaged or missing item claims must be reported within 7 calendar days of delivery. For immediate assistance, you may also call us at (213) 316-8849.
8. Order Cancellation
You may cancel your order without penalty if it has not yet been shipped. To cancel, email us at support@oneandes.com as soon as possible. If the order has already been processed or shipped, you will need to follow the standard return process upon receipt.
9. Warranty
All OneAndes batteries are backed by a 12-month limited warranty against defects in materials and workmanship. This warranty does not cover damage caused by misuse, improper charging, unauthorized modifications, normal wear and tear, or use outside of manufacturer specifications. For warranty claims, please contact our support team.
10. Contact Us
If you have any questions about our Return & Refund Policy, please reach out:
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Email: support@oneandes.com
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Phone: (213) 316-8849 (Mon-Fri, 9 AM – 5 PM Pacific Time)
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Mailing Address: 10320 6th St, Rancho Cucamonga, CA 91730, USA
We aim to respond to all inquiries within 24 hours during business days. Please include your order number for faster assistance.