What's in This Bundle
- 6x Samsung INR18650-20R4, 2,000mAh (max), Flat Top
- 1x XTAR MC4S 4-slot Type-C charger
- 1x XTAR MC1 single-slot Type-C charger
- Cables and manuals included with both chargers
This bundle exists because there's no clean single charger that handles exactly 6 cells at once. Rather than force you into a mismatched combo, we've paired the 4-slot MC4S with the compact single-slot MC1 — together they give you 5 charging slots, so 5 of your 6 cells can charge at the same time, with the last one following right behind. Both chargers use Type-C, so you're not juggling two different cable types either.
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 Flat Top. Looking for Button Top? Click here to buy: Samsung 20R4 Button Top + XTAR MC4S 4 + XTAR MC1 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. Six cells bought 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. Flat Top is the standard terminal type for most current devices — DIY packs, tool battery builds, and equipment that doesn't rely on spring-loaded contacts.
The MC4S handles four of the six cells with Type-C convenience and mixed Li-ion/Ni-MH/Ni-Cd charging support, while the MC1 covers the fifth as a small, genuinely portable backup charger you'll likely find other uses for.
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 |
Flat 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 Flat Top. For Button Top click here
XTAR MC4S — Charger Specs (4 Slots)
| Parameter |
Value |
| Input |
Type-C, DC 5V⎓2.1A |
| Charging Current |
1A×2 (CH1 & CH4) or 0.5A×4 (all slots occupied) |
| 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 |
| Charge Cut-off Voltage |
4.20V ±0.05V (Li-ion) / 1.5V (Ni-MH/Ni-Cd) |
| Charge 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 support the full range including 26650; CH2 & CH3 support up to 21700 only). 1.2V Ni-MH/Ni-Cd: AAAA, AAA, AA, A, SC, C |
| Notes |
Can fit two 26650 cells (CH1 & CH4) plus two unprotected 21700 cells (CH2 & CH3) at once; cannot charge protected 20700/21700 cells |
| Extra Feature |
0V activation; automatic chemistry detection for mixed Li-ion/Ni-MH/Ni-Cd charging |
| Status Indicators |
Red = charging/activating/slot short-circuit; Green = fully charged, no battery inserted, or poor contact; Blinking red+green = reverse polarity |
| Safety |
Overcurrent, overvoltage, overheat, and short-circuit protection |
XTAR MC1 — Charger Specs (1 Slot)
| Parameter |
Value |
| Input |
Type-C, 5V⎓1A |
| Charging Current |
1A (single slot, constant current) |
| Charge Cut-off Voltage |
4.2V ±0.05V |
| Charge Cut-off Current |
<130mA |
| Operating Temperature |
0°C to 40°C |
| Dimensions |
L103mm x W25mm x H30mm |
| Net Weight |
27g |
| Charging Method |
3-stage charging (trickle → constant current → constant voltage), automatic Li-ion detection |
| Compatible Cell Sizes |
3.6V/3.7V Li-ion: 10440, 14500, 14650, 16340, 17335, 17500, 17670, 18350, 18490, 18500, 18650, 18700, 20700, 21700, 22650, 25500, 26650; supports protected 21700 |
| Extra Feature |
"0V" activation technology — attempts recovery on over-discharged cells |
| Status Indicator |
Green = standby/fully charged, Red = charging, Off = reverse polarity or abnormal insertion |
| Safety |
Intelligent detection, auto cut-off, overcurrent/overcharge/overvoltage/short-circuit/reverse-polarity protection, soft-start |
| Package Includes |
MC1 charger, USB-C cable, user manual |
A realistic note on charging all 6: the four cells on the MC4S charge at 0.5A per slot with all four bays occupied, while the fifth cell on the MC1 charges at a faster 1A — so that fifth cell will actually finish first, in roughly 2-2.5 hours, while the MC4S batch takes closer to 4.5-5 hours. The 6th cell follows once a slot opens up. It's an asymmetric setup, but a genuinely economical way to cover six cells.
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. Both chargers enforce their 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.
-
Flat Top won't work in devices that specifically require Button Top cells — check your device's battery compartment before ordering if you're not sure which terminal type it needs.
-
Neither charger in this bundle has a display or capacity-testing function. If you want to verify these cells' actual capacity before building a pack, an analyzer-style charger like the VC4SL is worth the extra cost.
-
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
Can all 6 cells charge at the same time? 5 of the 6 can charge simultaneously — 4 on the MC4S, 1 on the MC1. The 6th cell follows once a slot frees up.
Why does the MC1 cell charge faster than the MC4S cells? The MC4S delivers 0.5A per slot when all four bays are occupied, while the MC1 delivers a full 1A to its single cell — so the MC1's cell finishes in roughly half the time. Both rates are safe for this cell; it's simply a difference in charger design.
Will Flat Top cells work in my device? If your device uses spring-loaded, flat, or magnetic-style contacts without a raised positive terminal requirement, Flat Top is the correct choice. If your device specifically calls for Button Top (a raised positive terminal), you'll want that version instead.
Does the MC4S also charge AA/AAA batteries? Yes — it automatically detects Ni-MH/Ni-Cd chemistry and applies a dedicated charging strategy alongside its Li-ion profile. The MC1 is Li-ion only.
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).
Is this kit protected-cell compatible? The MC1 supports protected 21700 cells; the MC4S does not support protected 20700/21700. The cells included in this bundle are unprotected bare cells, which is standard for this model.
In stock now. This bundle ships as a matched set of six Samsung INR18650-20R4 Flat Top cells with a genuine XTAR MC4S and MC1 charger combo — both Type-C, both dependable, ready for power tool and e-bike builds.
