What's in This Bundle
- 2x LG INR18650-MJ1, 3,500mAh, Button Top
- 1x XTAR MC2 dual-slot USB-C charger
- 1x USB-C charging cable (included with the charger)
A ready-to-go starter kit for anyone who needs two matched, genuine high-capacity 18650 cells and a compact way to charge them — no separate charger purchase, no guessing whether a charger you already own is a safe, appropriate match.
A note on Button Top length: converting the MJ1 to Button Top adds roughly 2mm to the cell's overall length compared to the native Flat Top version. This is standard for the conversion and shouldn't cause fit issues in devices designed for Button Top 18650s, but it's worth knowing if you're working with a tight battery compartment.
This listing is for Button Top. Looking for Flat Top? Click here to buy: LG INR18650-MJ1 Flat Top + XTAR MC2 Bundle.
Why This Pairing Makes Sense
The MJ1 was, at release, one of the highest-capacity 18650 cells on the market — LG's NMC811 chemistry with a silicon-graphite anode pushes energy density further than most cells in this size while still holding a genuine 10A continuous discharge rating. That combination makes it a strong fit for high-capacity flashlights, e-bike packs, and general electronics where runtime matters but you still want more current headroom than a pure energy cell like the NCR18650B provides. 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 than usual here, since independent testing has shown some batch-to-batch capacity variability with this cell.
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.
LG INR18650-MJ1 — Battery Specs
| Parameter |
Value |
| Brand & Model |
LG Chem INR18650-MJ1 |
| Chemistry |
NMC811 cathode, graphite-silicon anode |
| Capacity |
3,500mAh nominal (3,350mAh minimum) |
| Nominal Voltage |
3.635V average |
| Standard Charge |
0.5C (1.675A) CC, 4.2V CV, 50mA cutoff |
| Max Charge Voltage |
4.2V ±0.05V |
| Max Charge Current |
1.0C (~3.35A) |
| Standard Discharge |
0.2C (670mA), 2.5V cutoff |
| Max Continuous Discharge |
10A |
| Cycle Life |
400 cycles (charge 1.5A / discharge 4A) to 80% capacity |
| Charge Temperature |
0°C to 45°C |
| Terminal Type |
Button Top (+2mm length vs. Flat Top) |
| Protection Circuit |
None (unprotected cell) |
| Weight |
~49g max |
| Cell Dimensions |
Diameter 18.4mm (max 18.5mm), Height 65.0mm (max 65.2mm) |
A note on real-world capacity: independent lab testing has shown this cell's actual measured capacity can run somewhat below its 3,500mAh nominal rating in some batches — one third-party comparison test measured roughly 3,205-3,384mAh depending on discharge rate, noticeably below the datasheet figure. This isn't unique to the MJ1, but it's a genuine reason to prioritize matched-batch pairs (like this bundle) over mixing cells from different orders, and not to expect every unit to hit the nominal number exactly.
This listing is for Button Top . For Flat Top, click here
XTAR MC2 — Charger Specs
| 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: the MJ1's own standard charge current is 1.675A, meaningfully above the MC2's 1A per slot — expect a full charge in roughly 4.5-5 hours, both cells at once, a bit longer than lower-capacity cells in our MC2 bundle lineup since there's more capacity to fill and the charge rate is more conservative relative to the cell's spec.
Where the MJ1 Actually Fits
-
High-capacity flashlights and headlamps running moderate-to-high output modes
-
E-bike and e-scooter packs where 10A per cell in parallel is sufficient
-
General electronics packs prioritizing energy density with more current headroom than pure energy cells
-
DIY power banks and backup builds wanting more runtime per cell than lower-capacity options
Not the right choice for sub-ohm mechanical mods, or anything regularly demanding more than 10A per cell — for those, a dedicated high-drain cell like the Samsung 25R or 30Q is a better match.
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 cells with older ones you already own, even if they're also MJ1. Given the batch-to-batch capacity variability noted in independent testing, this matters more than it would for a more consistent cell.
-
10A is a real ceiling. Don't use these in devices that regularly demand more current than that.
Frequently Asked Questions
Can this charger handle the MJ1's full capacity safely? Yes. The MC2's 1A per slot is below the MJ1's own 1.675A standard charge current, so it's a conservative, safe rate — a full charge takes roughly 4.5-5 hours, both cells at once.
Why might my actual measured capacity come in under 3,500mAh? Independent testing has shown some batch-to-batch variation with this cell, with measured capacity sometimes landing in the 3,200-3,400mAh range depending on discharge rate and batch. It's still a genuine high-capacity cell — just worth knowing that the nominal figure is a typical rating, not a guarantee for every individual unit.
Does Button Top affect fit in my device? It adds roughly 2mm to the cell's overall length compared to Flat Top. Most devices designed for Button Top 18650s account for this, but it's worth checking your battery compartment if space is tight.
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.
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 genuine LG INR18650-MJ1 Button Top cells with a verified XTAR MC2 charger — ready for high-capacity flashlights, e-bikes, and general electronics out of the box.
Authentic LG Cells – sourced from official distributors. No rewraps, no fakes.
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