What's in This Bundle
- 4x Samsung INR18650-20R4, 2,000mAh (max), Button Top
- 1x XTAR MC4S 4-slot Type-C charger
- USB-A to USB-C charging cable and user manual included
A complete kit for anyone running a 4-cell high-drain device or building a small pack — four matched cells paired with a compact, genuinely portable 4-slot charger.
A note on "20R4": this is a distinct cell revision, not simply a batch label for the standard INR18650-20R. Based on the lab-test data available for this specific cell, it differs from the standard 20R in a couple of measurable ways — most notably a 20A max continuous discharge rating (versus 22A on the standard 20R) and a tighter internal resistance spec. We've sourced these numbers from supplier lab testing rather than a publicly available Samsung SDI datasheet. If you have a manufacturer spec sheet that differs from what's below, let us know before ordering.
This listing is for Button Top. Looking for Flat Top? Click here to buy: Samsung 20R4 Flat Top + MC4S Bundle.
Why This Pairing Makes Sense
Like the standard 20R, this is a lower-capacity, high-current cell suited to power tool packs, e-bike builds, and other applications where sustained current draw matters more than runtime per cell. Buying four cells together as a matched set means consistent capacity and internal resistance across the group — this matters more, not less, for a high-drain cell, since mismatched cells in a pack show up faster under heavy load. Button Top is the terminal type required by devices with spring-loaded battery contacts.
The XTAR MC4S is a genuine step up from the older Micro-USB MC4 — same compact footprint, but with a Type-C port (so you can charge from a laptop, wall adapter, or car charger without hunting for a specific cable) and mixed-chemistry support for Li-ion alongside Ni-MH/Ni-Cd cells in the same unit.
Samsung INR18650-20R4 — Battery Specs
| Parameter |
Value |
| Brand & Model |
Samsung INR18650-20R4 |
| Max Capacity |
2,000mAh |
| Min Capacity |
1,900mAh |
| Rated Voltage |
3.6V |
| Max Charge |
4A / 4.2V |
| Max Discharge |
20A / 2.5V cutoff |
| Internal Resistance |
14mΩ ±3 (lab-tested) |
| Net Weight |
~44g |
| Cell Dimensions |
Height 65mm, Diameter 18mm |
| Terminal Type |
Button Top |
| Protection Circuit |
None (unprotected cell) |
How this compares to the standard Samsung 20R: capacity is essentially the same (2,000mAh), and the max charge current matches (4A). The two measurable differences are discharge rating (20A here versus 22A on the standard 20R) and internal resistance, where this batch's lab-tested figure (14mΩ) runs lower than what's typically measured on standard 20R cells.
This listing is for Button Top. For Flat Top click here
XTAR MC4S — Charger Specs
| Parameter |
Value |
| Input |
Type-C, DC 5V⎓2.1A |
| Charging Current |
1A×2 or 0.5A×4 — current per slot depends on how many slots are in use |
| Charging Method |
TC-CC-CV 3-stage for Li-ion (trickle → constant current → constant voltage); precise 0ΔV/-ΔV full-charge detection for Ni-MH/Ni-Cd |
| Cut-off Voltage |
4.20V ±0.05V (Li-ion) / 1.5V (Ni-MH/Ni-Cd) |
| Cut-off Current |
≤70mA |
| Operating Temperature |
0°C to 40°C |
| Dimensions |
L100mm x W97mm x H26.5mm |
| Net Weight |
95g |
| Compatible Cell Sizes |
3.6V/3.7V Li-ion/IMR/INR/ICR: 10440, 14500, 14650, 16340, 17500, 17670, 18350, 18490, 18500, 18650, 18700, 20700, 21700, 22650, 25500, 26650 (CH1 & CH4 fit the full range including 26650; CH2 & CH3 fit up to 21700). 1.2V Ni-MH/Ni-Cd: AAAA, AAA, AA, A, SC, C |
| Notes |
Can fit two 26650 cells (outer slots 1 & 4) and two unprotected 21700 cells (inner slots 2 & 3) at once; cannot charge protected 20700/21700 cells |
| Extra Feature |
"0V activation" — can recover some over-discharged cells; automatically detects battery chemistry and switches charging strategy for mixed Li-ion/Ni-MH/Ni-Cd charging |
| LED Indicators |
Red = charging/activating/slot short-circuit; Green = fully charged, no battery inserted, or poor contact; Red+Green flashing = reverse polarity (reinsert correctly) |
| Safety |
Overcurrent, overvoltage, overheat, and short-circuit protection |
A realistic note on charge time: with all four bays occupied, the MC4S delivers 0.5A per slot — expect a full charge in roughly 4.5-5 hours for all four cells at once. That's not the fastest option in our lineup, but it's a genuinely portable, Type-C-powered charger you can run from a laptop, wall adapter, or car charger without carrying a dedicated power brick.
Where This Cell Fits
-
Power tool battery packs — cordless drills, saws, and similar tools that draw hard and often
-
E-bike and e-scooter packs — commonly used in multi-cell parallel configurations
-
DIY packs prioritizing current over runtime, especially builds where consistent internal resistance across cells matters for pack balance
Not the right choice if you want strong runtime from a small number of cells, or if you need the slightly higher 22A ceiling of the standard 20R for a specific application.
Things Worth Knowing Before You Use This Kit
-
This is an unprotected cell. The charger enforces its own voltage and current cutoffs, but your device still needs to handle discharge-side protection.
-
Don't mix these with standard 20R cells or older 20R4 batches in the same pack. Even with similar specs, small differences in internal resistance or capacity between cells can cause imbalanced charging over time.
-
This is a lower-capacity cell by design, whether standard 20R or 20R4 — don't expect 25R or 30Q-level runtime from it.
Frequently Asked Questions
What's actually different between this and the standard Samsung 20R? Based on the lab data we have for this batch, capacity and max charge current are essentially the same. The measurable differences are a slightly lower max continuous discharge rating (20A vs. 22A) and a tighter, lower internal resistance spec (14mΩ vs. the standard 20R's typical range).
How is the MC4S different from the older MC4? Same compact size and the same 1A×2/0.5A×4 charging current, but the MC4S uses a Type-C port instead of Micro-USB, and it can also charge Ni-MH/Ni-Cd cells (AA, AAA, etc.) with automatic chemistry detection — the older MC4 doesn't offer that mixed-chemistry support.
Can I charge two different cell sizes at once? Yes, within limits — the outer two slots (1 & 4) fit larger cells up to 26650, while the inner two (2 & 3) handle sizes up to unprotected 21700. Protected 20700/21700 cells won't fit or charge on this charger.
Is this kit protected-cell compatible? No — the MC4S cannot charge protected 20700/21700 cells. The cells included in this bundle are unprotected bare cells, which is standard for this model and compatible with the charger.
What does the "0V activation" feature do? It lets the charger attempt a slow, controlled charge on cells drained deep enough that a standard charger would refuse to recognize them at all. It won't save every over-discharged cell, but it can recover some that would otherwise be written off.
In stock now. This bundle ships as a matched set of four Samsung INR18650-20R4 Button Top cells with a genuine XTAR MC4S charger — compact, Type-C powered, and ready for power tool and e-bike builds out of the box.
