Why This Bundle
High-drain batteries deserve a charger that can actually keep up with them. Overcharging, swelling, and no way to check cell health are the most common risks with mismatched charging setups. This bundle pairs genuine Samsung 25R Flat Top cells with the XTAR VC8S smart charger, so you get a matched, ready-to-use setup right out of the box — no guesswork on compatibility or safety.
This listing is for Flat Top. Looking for Button Top? Click here to buy: Samsung INR18650-25R Button Top + XTAR VC8S Bundle.
Samsung INR18650-25R (Flat Top) Specifications
| Item |
Spec |
| Model |
Samsung INR18650-25R (Flat Top) |
| Rated Capacity |
2500mAh |
| Nominal Voltage |
3.6V |
| Max Continuous Discharge |
20A |
| Charge Cutoff Voltage |
4.2V |
| Chemistry |
NMC (Lithium Nickel Manganese Cobalt Oxide) |
| Cell Size |
18650 (approx. Φ18.3mm × 65.0mm) |
| Terminal Type |
Flat Top — level positive terminal, suited for devices requiring full-surface contact |
| Typical Use |
Battery packs, power banks, flashlights, power tools, e-bikes, and other devices designed for flat-top cells |
Note: High-drain cells demand careful handling — 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: XTAR VC8S
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8-bay Type-C LCD display with independent charging channels
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True Capacity Test (Grad.): charge–discharge–charge low-current analysis reveals the real capacity of each 25R cell, flagging degraded ones early
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Internal Resistance Test (IR): checks the health of every cell so you can pick out the best-performing ones for high-drain use
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Smart Recognition + Trickle-CC-CV: automatically applies the optimal charging curve for 25R cells
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PD Fast Charging: Type-C input, up to 3A on 2 bays with a 15V/3A power source
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Reverse-Polarity Protection + Over-Discharge Repair: dual safety features that extend battery lifespan
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5 Adjustable Current Levels: 3A / 2A / 1A / 0.5A / 0.25A to match different charging needs
VC8S Charger – Supported Battery Types & Voltage
Compatible battery length: 30–80mm
3.6V/3.7V Li-ion/IMR/INR/ICR batteries: 10440, 14500, 14650, 16340, 17500, 17670, 18350, 18490, 18500, 18650, 18700, 20700, 21700, 22650, 25500, 26650 — including the Samsung 25R (18650) in this bundle (Charges batteries with or without a protection circuit board)
1.2V NiMH batteries: AAA, AA, A, SC, C (Note: Not compatible with 1.5V rechargeable lithium batteries)
Charge cutoff voltage: 4.20±0.05V (Li-ion) / 1.45±0.1V (NiMH)
Compatibility Notes
The VC8S uses a spring-loaded contact design, so Flat Top batteries seat securely without any adapter — the springs take up the extra length automatically. Samsung 25R Flat Top cells measure about 65.0mm, which sits comfortably within the VC8S's 30–80mm battery length range.
What's Included
- Samsung INR18650-25R Flat Top Battery × 8
- XTAR VC8S Charger × 1
- User Manual × 1
- USB-C to USB-C Charging Cable × 1
- USB-A to USB-C Charging Cable × 1
This listing is for Flat Top. For Button Top click here
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
- Run a capacity test on the VC8S before first use to confirm each cell's condition
- These are high-drain cells intended for compatible, purpose-built devices — do not use them in unauthorized or modified equipment
- Flat Top batteries are commonly used in devices with spring or flat-contact battery holders (e.g., battery packs and power tools) — check your device's terminal requirements before use
FAQ
Q: Can the XTAR VC8S charge Samsung 25R Flat Top batteries safely? A: Yes. The VC8S automatically recognizes Li-ion chemistry and applies a Trickle-CC-CV charging profile matched to 25R cells, with a 4.2V cutoff voltage.
Q: What's the difference between Flat Top and Button Top batteries? A: The only difference is the shape of the positive terminal — Flat Top is level for full-surface contact, while Button Top has a raised nub. Capacity, voltage, and discharge rate are identical.
Q: Will Flat Top batteries sit properly in the VC8S charger slots? A: Yes. The VC8S's spring-loaded contacts are designed to accommodate both Flat Top and Button Top cells without any adapter or modification.
Q: How many 25R batteries can I charge on the VC8S at the same time? A: All 8 bays can charge simultaneously. For faster charging (3A or 2A), fewer bays are used at once — see the current level table in the VC8S charger listing for details.
Q: How do I know if a 25R battery is degraded? A: Run the VC8S's Capacity Test (Grad.) mode. It performs a charge–discharge–charge cycle and displays the battery's true remaining capacity, making it easy to spot cells that have aged or lost performance.
Q: Is 20A continuous discharge safe for everyday devices? A: These are high-drain cells built for devices that specifically call for high continuous discharge, such as certain power tools, flashlights, and DIY battery packs. Always check your device's battery requirements before use.
Q: What's in the box? A: 8 Samsung INR18650-25R Flat Top batteries, 1 XTAR VC8S charger, a user manual, a USB-C to USB-C cable, and a USB-A to USB-C cable.
