Why This Bundle
The Molicel P28A takes the acclaimed P26A formula and pushes the capacity a bit further — 2800mAh at the same 35A continuous discharge rating, with the same low internal resistance and flat voltage curve under load. A cell this capable deserves a charger that treats it right. This bundle pairs 2 genuine Molicel INR18650-P28A Flat Top batteries with the NITECORE UI2 — a compact, USB-C powered charger that automatically selects the right charging mode and includes trickle charging and over-discharge protection. Everything you need to charge and maintain your cells, ready out of the box.
Molicel INR18650-P28A (Flat Top) Specifications
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| Item |
Spec |
| Model |
Molicel INR18650-P28A (Flat Top) |
| Typical Capacity |
2800mAh |
| Minimum Capacity |
2600mAh |
| Nominal Voltage |
3.6V |
| Max Continuous Discharge |
35A (rated with 80°C thermal cutoff) |
| Standard Charge Current |
2.8A |
| Maximum Charge Current |
6A |
| Charge Cutoff Voltage |
4.20±0.05V |
| Discharge Cutoff Voltage |
2.5V |
| Internal Resistance |
≤20mΩ (AC 1kHz) |
| Chemistry |
INR (Lithium Nickel Manganese), high-drain |
| Cell Size |
18650 (approx. |
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Φ18.5mm × 65.15mm) |
Terminal Type |
Flat Top — level positive terminal, suited for devices requiring full-surface contact |
Typical Use |
Power tools, high-output flashlights, electric mobility, battery pack builds, and other demanding high-drain applications |
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Note: This is a high-drain, unprotected cell — avoid mixing with batteries of a different brand, model, or charge state, and inspect the wrap for damage before every use to prevent short circuits.
The Charger: NITECORE UI2
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USB-C input: charge from any 5V power bank, solar panel, or USB adapter — great for travel and outdoor use
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Automatic CC/CV Charging: intelligently selects the most suitable charging mode for each cell
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Independent Dual-Bay Control: each of the 2 bays charges independently without affecting the other
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Trickle Charging: automatically switches to 100mA trickle mode for batteries below 2.9V, then up to 1000mA standard charging above 2.9V
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Over-Discharge Activation: automatically detects and reactivates over-discharged protected Li-ion cells
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Multiple Safety Protections: reverse-polarity/short-circuit protection, intelligent temperature control, and overcharge protection
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Ultra-Compact & Lightweight: just 79.5g, 125.5 × 59.5 × 32.1mm
NITECORE UI2 – Supported Battery Types & Voltage
Charges 3.6V/3.7V Li-ion/IMR batteries, including the Molicel P28A (18650) in this bundle:
10340, 10350, 10440, 10500, 12340, 12500, 12650, 13450, 13500, 13650, 14430, 14500, 14650, 16500, 16340 (RCR123), 16650, 17350, 17500, 17650, 17670, 18350, 18490, 18500, 18650, 20700, 21700, 22500, 22650, 25500, 26500, 26650
Output voltage: 4.2V±1% Output current: up to 1000mA per bay (max 2 bays simultaneously)
Compatibility Notes
The UI2's charging bays are open-ended, allowing Flat Top batteries to seat securely without any adapter. P28A Flat Top cells measure about 65.15mm, well within the UI2's compatible battery range.
Note: The UI2 charges at up to 1000mA per bay, which is below the P28A's 2.8A standard charge current. Expect a longer, gentler charge cycle — good for cell longevity, but budget extra time versus a high-current dedicated charger.
What's Included
- Molicel INR18650-P28A Flat Top Battery × 2
- NITECORE UI2 Charger × 1
- USB-C Charging Cable × 1
- User Manual × 1
Safety Tips
- Store batteries in a proper case, keeping them away from loose metal objects to prevent short circuits
- Never disassemble, puncture, burn, or submerge the batteries
- Charge only with a genuine, compatible charger such as the NITECORE UI2
- The P28A is an unprotected, high-drain cell intended for compatible, purpose-built devices — do not use it in unauthorized or modified equipment
- Never discharge below 2.5V or charge above 4.2V
FAQ
Q: Can the NITECORE UI2 charge Molicel P28A Flat Top batteries safely? A: Yes. The UI2 automatically selects the optimal CC/CV charging mode for Li-ion cells like the P28A, with a 4.2V±1% output voltage and up to 1000mA per bay.
Q: Will Flat Top batteries sit properly in the UI2 charger bays? A: Yes. The UI2's open charging bays are designed to accommodate both Flat Top and Button Top cells without any adapter or modification.
Q: Can I charge both batteries at the same time? A: Yes. The UI2 has 2 independent bays, each capable of up to 1000mA, and one battery's charging status does not affect the other.
Q: Can I power the UI2 with a power bank while traveling? A: Yes. The UI2 has a USB-C input and works with any 5V power source, including power banks, solar panels, and USB wall adapters.
Q: What happens if a P28A battery has over-discharged? A: The UI2 includes an over-discharge activation feature that automatically detects and reactivates protected Li-ion cells that have dropped too low from storage or improper use. Note that the P28A is an unprotected cell, so always avoid discharging it below 2.5V in the first place.
Q: Is 35A continuous discharge safe for everyday devices? A: No — the P28A is a high-drain cell intended strictly for devices specifically engineered for high continuous discharge, such as certain power tools, and high-output flashlights. Always check your device's battery requirements before use.
Q: How does the P28A compare to the P26A? A: Both share the same 35A discharge rating and low internal resistance, performing almost identically under heavy load. The P28A offers a bit more capacity (2800mAh vs. 2600mAh), giving slightly longer runtime in lower-power situations.
Q: What's in the box? A: 2 Molicel INR18650-P28A Flat Top batteries, 1 NITECORE UI2 charger, a USB-C charging cable, and a user manual.
