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A ready-to-go starter kit for anyone who needs two matched, genuine high-drain 18650 cells and a compact way to charge them — no separate charger purchase, no guessing whether a charger you already own is a safe match for these cells.
This listing is for Button Top. Looking for Flat Top? Click here to buy: Samsung 20R4 Flat Top + XTAR MC2 Bundle.
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 listed the numbers we have below and sourced them from supplier lab testing rather than a publicly available Samsung SDI datasheet, since we haven't located one specific to this revision. If you have a manufacturer spec sheet that differs from what's below, let us know before ordering.
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. Button Top is the terminal type required by devices with spring-loaded battery contacts. Buying two cells together as a matched pair means you're starting with cells from a similar batch — which matters more for a high-drain cell like this one, since mismatched internal resistance between cells in a pack shows up faster under heavy load.
We chose the MC2 for this bundle not just for its steady 1A charge, but also for its 0V activation technology — it can safely revive over-discharged 20R4 cells that other chargers would simply reject. This one feature alone can save you from throwing away a perfectly good battery.
The XTAR MC2 pairs well here because it charges both slots at a full 1A simultaneously, with no current-splitting trade-off for using both bays at once — a comfortable, conservative rate relative to this cell's 4A max charge spec.
| 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 — generally a sign of more consistent manufacturing, though we'd rather show you the actual numbers than round them into "identical."
| Parameter | Value |
|---|---|
| Input | Type-C, 5V⎓2A |
| Charging Current | 1A per slot — both slots simultaneously, no splitting |
| Charging Method | 3-stage charging (trickle → constant current → constant voltage), 2 independent slots with automatic detection |
| End-of-Charge Voltage | 4.2V ±0.05V |
| End-of-Charge Current | <130mA cutoff |
| Operating Temperature | 0°C to 40°C |
| Dimensions | L103mm x W53mm x H30mm |
| Weight | 54g |
| Compatible Cell Sizes | 3.6V/3.7V Li-ion, sizes 10440 through 26650 (10440, 14500, 14650, 16340, 17335, 17500, 17670, 18350, 18490, 18500, 18650, 18700, 20700, 21700, 22650, 25500, 26650), including protected 21700 cells |
| Extra Feature | "0V" activation technology — can recover some over-discharged cells |
| Status Indicators | Green = standby/fully charged, Red = charging, Off/unlit = reverse polarity or abnormal insertion |
| Safety | Reverse polarity protection, short-circuit protection, 3-stage charge control |
A realistic note on charge time: at 1A per slot against a 4A max charge rating, you've got real margin here — a full charge from empty takes roughly 2-2.5 hours, both cells at once.
This listing is for Button Top . For Flat Top, click here
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.
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). We'd rather give you the real numbers than claim the two cells are identical.
Can this charger handle this cell's full capacity safely? Yes. The MC2's 1A per slot is comfortably under this cell's 4A max charge rating — a full charge takes roughly 2-2.5 hours, both cells at once.
Can I charge two different battery sizes at once? Yes — the MC2's two slots operate independently with automatic size and chemistry detection, so you could charge one 18650 and a differently-sized cell (like a 21700) at the same time if needed.
Is this kit protected-cell compatible? The MC2 supports protected 21700 cells if you use it for those later. The cells included in this bundle are unprotected bare cells.
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 pair of Samsung INR18650-20R4 Button Top cells with a verified XTAR MC2 charger — ready for power tool packs, e-bike builds, and other high-drain applications out of the box.
Authentic Samsung Cells – sourced from official distributors. No rewraps, no fakes.
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Delivery Time: Once shipped, orders typically arrive within 7–15 business days.
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The distinctive Samsung wrapper on these 20R cells has survived drops and rough handling in my workshop without damage.
The 20R cells stay surprisingly cool even at full 20A discharge. The MC2 charger manages temperature well during charging.
If you are new to high-drain 18650 applications, this Samsung 20R kit provides genuine 20A cells and a safe reliable charger.
I have about 120 cycles on my first pair of 20R cells. They still test at over 1900mAh. Samsung durability even in high-drain applications.
Buying the cells and charger together in this bundle is significantly cheaper than purchasing individually. Great value for high-drain power.
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