Samsung INR21700-50S 5000mAh 20A 21700 Battery 4-Pack with Nitecore UMS4 Smart Charger – Reliable High-Power Kit for Tactical Gear, Heavy-Duty Tools & High-Torque E-Mobility

Why This Bundle

The Samsung 50S steps up from the 50E with the same 5000mAh capacity but a significantly higher discharge ceiling — 20A continuous without a temperature cutoff, or up to 35A with an 80°C thermal cutoff — making it a stronger choice for e-bikes, power tools, and drones that need both energy and real current delivery. A set this capable deserves a charger that can handle every cell at once while keeping close watch on their health. This bundle pairs 4 genuine Samsung INR21700-50S batteries with the NITECORE UMS4, a QC-enabled 4-slot charger with a detailed LCD display, independent bay control, and multiple layers of protection — ready to use straight out of the box.

Samsung INR21700-50S Specifications

Note: Samsung's own product positioning lists the 50S for EV, e-bike, drone, power tool, and e-mobility applications, and explicitly states it is not intended for e-cigarettes, flashlights, RC cars, or electric skateboards.

This is an 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 UMS4

• USB-C input with QC support: up to 4,000mA total output; up to 3,000mA on a single bay with a QC adapter — the closest match here to the 50S's 2.5A standard charge current
• QC Mode output: 3,000mA×1 / 2,000mA×2 / 1,000mA×4 — Standard Mode: 2,000mA×1 / 1,000mA×2 / 500mA×4
• Independent 4-bay control: charge and monitor up to 4 batteries separately, with each bay unaffected by the others
• Detailed real-time LCD display: shows battery health (Good/Poor), internal resistance, charging current, voltage, battery type, charged capacity, charging time, cut-off voltage, and charging mode
• 3 automatic charging modes: CC, CV, and -dV/dt, selected automatically based on battery type and charge level
• Manual adjustment: set charging voltage and current for specialized battery types
• Safety features: automatic internal resistance detection, reverse-polarity and short-circuit protection, overtime charging protection, and over-discharged battery activation/restoration
• Fire-retardant PC/ABS housing with built-in temperature regulation
• Universal power input: works with wall adapters, power banks, and solar panels via USB-C

NITECORE UMS4 – Supported Battery Types & Voltage

Compatible with 3.6V/3.7V Li-ion, 3.8V Li-ion, 3.2V LiFePO4, and 1.2V Ni-MH/Ni-Cd batteries, including the Samsung 50S (21700) in this bundle:

IMR/Li-ion/LiFePO4: 10440, 14500, 14650, 16500, 16340 (RCR123), 16650, 17350, 17500, 17650, 17670, 17700, 18350, 18490, 18500, 18650, 18700, 20700, 21700, 22500, 22650, 25500, 26500, 26650, 26700 Ni-MH/Ni-Cd: AA, AAA, AAAA, C, D

Output current: up to 3,000mA per bay (QC mode) / 4,000mA total

Compatibility Notes

The UMS4 uses spring-loaded contacts and its bays are sized to comfortably fit 21700 cells like the 50S. Unlike a basic dual-slot travel charger, the UMS4's per-bay output (up to 3,000mA with a QC adapter on a single bay) lines up much more closely with the 50S's 2.5A standard charge current, making full charges considerably faster than a low-current charger would allow.

Note: With all 4 bays occupied, each will charge more gently at up to 1,000mA (QC mode) or 500mA (standard mode) — slower than the 50S's rapid-charge rating, but a reasonable, safe charging pace for four cells at once.

What's Included

• Samsung INR21700-50S Battery × 4
• NITECORE UMS4 4-Bay 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 UMS4
• The 50S is an unprotected cell intended for compatible, purpose-built devices such as EVs, e-bikes, drones, and power tools — it is not intended for e-cigarettes, flashlights, RC cars, or electric skateboards
• Never discharge below 2.5V or charge above 4.2V

FAQ

Q: Can the NITECORE UMS4 charge Samsung 50S batteries safely? A: Yes. The UMS4 automatically detects Li-ion chemistry and applies the correct charging voltage (4.2V) and current for 50S cells, with real-time monitoring on its LCD display, and its higher per-bay output charges these cells noticeably faster than a basic low-current charger.

Q: Is the Samsung 50S suitable for  flashlights? A: No. Samsung's own product positioning explicitly states this cell is not intended for  flashlights, RC cars, or electric skateboards. It's built for EVs, e-bikes, drones, power tools, and e-mobility applications.

Q: How does the 50S compare to the 50E? A: Both share the same 5000mAh capacity, but the 50S has a meaningfully higher discharge ceiling — 20A continuous (35A with thermal cutoff) versus the 50E's 9.8A — making the 50S the better pick for applications that need more current alongside the capacity.

Q: Can I charge all 4 batteries at the same time? A: Yes. The UMS4 has 4 independent bays and can charge all 4 cells simultaneously — up to 1,000mA per bay in QC mode, or 500mA per bay in standard mode, when all 4 slots are used at once.

Q: Will 21700 batteries fit properly in the UMS4? A: Yes. The UMS4's bays and spring-loaded contacts are sized to accommodate 21700 cells like the 50S without any adapter.

Q: How do I know if a 50S battery is degraded? A: The UMS4's LCD display shows battery health as "Good" or "Poor" along with internal resistance readings, making it easy to spot cells that have aged or lost performance.

Q: What's in the box? A: 4 Samsung INR21700-50S batteries, 1 NITECORE UMS4 charger, a USB-C charging cable, and a user manual.